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. 2025 Aug 5;15:28489. doi: 10.1038/s41598-025-14627-3

Acute cardiorespiratory physiological responses to functional electrically stimulated cycling in individuals with subacute phase traumatic cervical spinal cord injury

Zhenzhen Gao 1, Yajun Mao 1, Shiyan Wang 1, Zhiwen Zhu 1,✉
PMCID: PMC12325921  PMID: 40764811

Abstract

This study aims to assess the cardiovascular, respiratory, and gas metabolic responses elicited during functional electrical stimulation (FES)-cycling exercise in individuals with subacute traumatic motor-complete cervical spinal cord injury (CSCI) classified as ASIA Impairment Scale (AIS) grades A and B. This assessment was conducted utilizing cardiopulmonary exercise testing (CPET). Participants who met the eligibility criteria, characterized by subacute traumatic motor-complete CSCI, first underwent static pulmonary function testing. This was followed by a recumbent FES-cycling protocol, which involved incremental speed increases of 5 revolutions per minute (RPM). Throughout the exercise, continuous monitoring of electrocardiographic data, blood pressure, respiratory parameters, and gas metabolism was performed using CPET. Key physiological metrics, including minute ventilation (VE), tidal volume (VT), systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), oxygen uptake (VO2), and oxygen pulse (O2 pulse), were recorded at 2-minute intervals. A total of 18 participants in the subacute phase of recovery, with an injury duration ranging from 19 to 61 days, completed the study. Static pulmonary function testing indicated the presence of restrictive ventilatory dysfunction in all participants, with 22.2% exhibiting concurrent obstructive ventilatory dysfunction and 77.8% demonstrating a reduced ventilatory reserve. During FES-cycling exercise, significant inter-phase variations were observed across all measured parameters (p < 0.05). The variables of VE, SBP, DBP, HR, VO2, and O2 pulse exhibited concordant trends with the progression of RPM, with statistically significant differences identified between successive phases for VE, VO2, and O2 pulse (p < 0.05). Conversely, VT displayed discordant trends in relation to RPM. Individuals in the subacute phase of traumatic motor-complete CSCI demonstrate significant acute cardiorespiratory physiological responses to FES cycling exercise. These responses encompass an augmentation in VE, VT, and VO2, concomitant with an escalation in HR, O2 pulse, and BP.

Supplementary Information

The online version contains supplementary material available at 10.1038/s41598-025-14627-3.

Keywords: Functional electrical stimulation, Cervical spinal cord injury, Subacute phase, Cardiopulmonary exercise testing

Subject terms: Spinal cord diseases, Cardiac device therapy

Introduction

Traumatic spinal cord injury (SCI) represents a clinically significant and profoundly disabling condition, with an incidence rate in China estimated at approximately 65 cases per million individuals. Cervical spinal cord injury (CSCI) is the most prevalent and impactful subtype1, primarily characterized by paralysis of the limbs and compromised function of the diaphragm, intercostal muscles, and abdominal muscles. This neuromuscular impairment leads to respiratory failure, limited thoracic expansion, and reduced cough and expiratory capacity, resulting in mixed ventilatory dysfunction2. Additionally, high-level SCI is associated with complex cardiovascular impairments linked to autonomic dysfunction, including bradycardia, neurogenic shock, orthostatic hypotension, autonomic dysreflexia (AD)3, impaired left ventricular systolic function4, myocardial atrophy, left ventricular diastolic dysfunction, and decreased cardiac mass5. These pathophysiological changes are correlated with an increased risk of cardiovascular disease, with a positive association observed between the severity and level of injury and the extent of cardiovascular compromise6–8. Consequently, it is imperative to effectively address the cardiopulmonary damage caused by CSCI in order to enhance their health status.

Functional electrical stimulation (FES) involves electrically induced coordinated contractions of targeted muscles to generate functional movements. It has been widely utilised in motor rehabilitation for individuals with SCI9,10. Current evidence-supported benefits include mitigation of systemic inflammation, improvements in pulmonary function11, muscle health and aerobic metabolic capacity12. Sanna et al. conducted a 6-month FES-cycling exercise therapy intervention on five individuals with complete SCI. MRI results showed a significant 34% increase in muscle mass in the major muscle groups of the lower limbs, which was correlated with peak power13. Berkelmans et al. found that multi-channel FES-assisted gait training can improve the walking ability of individuals with chronic SCI14. Another study by Shaffer et al. showed that the improvement in aerobic capacity with FES-rowing in SCI populations was inversely proportional to time since injury and that the higher the level of injury, the more pronounced the increase in oxygen uptake (VO2) was15. The benefits of these long-term interventions may be closely related to the cardiopulmonary physiological responses activated by FES. For instance, Fornusek et al. found that heart rate (HR), VO2, and cardiac output exhibited significantly higher levels in subjects during FES-cycling exercise in comparison to the resting state16.

Additionally, research by Bakkum et al. also demonstrates that mixed FES-cycling exercise elicited a greater increase in HR and minute ventilation (VE) compared to handcycling at equivalent levels of subjective exercise intensity17. The existing body of research predominantly focuses on patients with chronic SCI, resulting in a notable deficiency in studies examining the application of FES-cycling exercise in subacute SCI populations. Consequently, there is a critical need to explore the cardiorespiratory physiological effects of early FES-cycling exercise in individuals with high-level SCI. Based on prior research findings, we hypothesize that FES-cycling exercise can elicit acute cardiopulmonary physiological responses in individuals with motor-complete CSCI during the subacute phase. These responses are anticipated to encompass elevated VE, tidal volume (VT), and VO2, alongside increases in HR and BP.

Currently, the primary modalities of exercise utilizing FES for individuals with SCI include upper limb hand cycling, lower limb cycling, mixed cycling, and rowing exercises18. Additionally, upper limb hand cycling and wheelchair roller systems are frequently employed to enhance exercise loads during cardiopulmonary exercise testing (CPET)19. Individuals with subacute-phase traumatic CSCI may encounter several challenges when engaging in FES-cycling or CPET in a seated position. These challenges include: (1) persistent hypotension, postural hypotension, or post-exercise hypotension20,21; (2) difficulty in maintaining balance while seated; (3) insufficient residual upper limb muscle strength, which hinders the completion of upper limb hand cycling exercises; and (4) reluctance to engage in early FES-cycling exercises in a seated position due to concerns about neck discomfort or cervical stability. Consequently, this study represents the first attempt to enable individuals with subacute-phase traumatic motor-complete CSCI to perform recumbent FES-cycling exercises. The entire process was monitored using the CPET system to preliminarily investigate the cardiorespiratory acute physiological responses when this group of people performs FES-cycling exercise.

Methods

Participants

Participants in this study were individuals experiencing traumatic subacute phase motor-complete CSCI, who were admitted to the Department of Rehabilitation Medicine at the First Affiliated Hospital of Zhejiang Chinese Medical University between January 2024 and March 2025. The inclusion criteria were as follows: (1) classification as ASIA Impairment Scale (AIS) A or B with neurological injury levels between C5 and C8; (2) age range of 18 to 65 years; (3) post-injury duration of less than three months; and (4) independence from mechanical ventilation and tracheal intubation. The exclusion criteria encompassed: (1) the presence of severe concomitant traumatic brain injury, cardiovascular disorders, or respiratory diseases; (2) significant cognitive, visual, or auditory impairments; (3) spinal or fracture instability; (4) use of medications affecting HR or blood pressure regulation; and (5) contraindications to FES-cycling exercise, such as cardiac pacemakers or lower limb deep vein thrombosis. The study protocol received approval from the Institutional Ethics Committee of the First Affiliated Hospital of Zhejiang Chinese Medical University (Approval No. 2023-KLS-113-01). The research was conducted in strict adherence to relevant guidelines and regulations, and informed consent was obtained from all participants and/or their legal guardians, and the study adhered to the Declaration of Helsinki.

Cardiopulmonary function assessment

A cardiopulmonary evaluation was performed utilizing the Master Screen CPX system (Jaeger, Germany). Participants were instructed to refrain from consuming high-fat foods, caffeine, and alcohol for 24 h prior to the assessment, and to ensure bladder and bowel evacuation before testing. Calibration procedures encompassed the verification of spirometer accuracy, alignment of the flow sensor, and normalization of the gas analyzer. Standard preparation procedures included: (1) placement of 12-lead ECG electrodes, (2) application of a brachial blood pressure cuff using the oscillometric method, (3) use of finger pulse oximetry, and (4) fitting of a sealed breathing mask with minimal dead space.

Static pulmonary function testing

Spirometry was conducted in accordance with the 2019 Standardization of Spirometry Update (joint ATS/ERS technical statement)22and the Spirometry Testing Standards in SCI23. Participants performed maximal inspiratory efforts followed by forced rapid exhalation to residual volume. Three technically acceptable maneuvers were recorded, with the highest-quality trial selected for analysis. Key parameters assessed included the forced vital capacity as a percentage of predicted (FVC%pred) and the ratio of forced expiratory volume in one second to FVC (FEV1/FVC%). Subsequently, maximal voluntary ventilation (MVV) was assessed through 12-second maximal-effort breathing24.MVV% predicted values were derived using population-specific reference equations.

Cardiopulmonary exercise testing

The testing protocol conformed to the principles delineated in the American College of Sports Medicine’s Guidelines for Exercise Testing and Prescription (9th Edition)25, encompassing four sequential phases (Fig. 1A): (1) Baseline: a 2-minute rest period; (2) FES-cycling exercise: an 8-minute recumbent FES-cycling exercise with incremental speed progression (increasing by 5 RPM every minute, up to a maximum of 40 RPM); (3) Recovery: an active cool-down phase at 20 RPM for 1 min, followed by 10 RPM for another minute; (4) Post-recovery: a 2-minute resting observation period. A 12-channel feedback-controlled FES cycle ergometer (SYCO3PL, Changzhou Siyu Medical Equipment Co., Ltd.) was employed to facilitate “active” cycling simulation. Stimulation electrodes were bilaterally placed over the quadriceps femoris (vastus lateralis/medialis), biceps femoris, and triceps surae (gastrocnemius/soleus) (Fig. 1B). The electrical parameters were as follows: pulse width ranged from 300 to 450 µs, individualized based on motor threshold; amplitude was set at 140 mA (constant current); frequency ranged from 20 to 40 Hz, initiated at the lower range and titrated to achieve observable muscle contraction12. The CPET system was subject to continuous monitoring throughout the experiment, with HR, blood pressure, VO2, oxygen pulse (O2 pulse), VE, and VT recorded at two-minute intervals. The mean values for the final 30 s were then calculated.

Fig. 1.

Fig. 1

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FES electrode sheet position and complete motion programme. (A) Complete motor programme; (B) 12-channel stimulation electrode sheet position.

Statistical analysis

Descriptive statistics characterised baseline demographics: customarily distributed continuous variables were expressed as mean (standard deviation, SD), while categorical variables were reported as counts (percentages). For CPET data across sequential timepoints, repeated-measures analysis of variance (RM-ANOVA) was employed. Mauchly’s test indicated violations of sphericity assumptions, necessitating Greenhouse-Geisser epsilon corrections. Where RM-ANOVA revealed significant time effects (p < 0.05), Tukey’s honestly significant difference post hoc tests were conducted to compare pre-exercise versus post-recovery resting states and evaluate inter-phase differences between adjacent timepoints during exercise progression. All analyses were performed using SPSS 27.0 (IBM Corp., Armonk, NY, USA)with statistical significance defined as p < 0.05 (two-tailed).

Results

Baseline characteristics of study participants

All eighteen enrolled participants (male: 14 [77.8%], female: 4 [22.2%]) completed the study protocol. Demographic and clinical characteristics were as follows: Age: 45.4 ± 12.4 years; Anthropometrics: Height: 171.9 ± 6.8 cm, Weight: 67.6 ± 8.1 kg, Body Mass Index(BMI): 22.80 ± 1.60 kg/m2; Time since injury: 36.5 ± 11.9 days; AIS A (n = 10, 55.6%), AIS B (n = 8, 44.4%); Injury mechanisms: Traffic accidents: 5 cases (27.8%), Falls from height: 10 cases (55.6%), Ground-level falls: 2 cases (11.1%), Crush injuries: 1 case (5.5%). Per ERS/ATS technical standards for pulmonary function interpretation26, restrictive ventilatory dysfunction was universally present, concurrent obstructive ventilatory dysfunction was observed in 4 participants (22.2%), and reduced ventilatory reserve was identified in 14 participants (77.8%). The baseline characteristics of the entire study cohort are delineated in Table 1.

Table 1.

Baseline characteristics of study participants.

SP Age (years) Gender Height (cm) Weight (kg) BMI (kg/m2) IM AIS NP TSI (days) FVC
% pred		 FEV1/FVC% MVV% pred
1 29 M 176 75 24.2 TA A C6 25 46% 97% 64%
2 34 M 178 69 21.8 FFH B C5 40 51% 94% 86%
3 46 F 162 54 20.6 FFH A C7 61 46% 97% 52%
4 53 M 170 66 22.8 TA B C5 28 44% 92% 58%
5 55 M 168 72 25.5 GIF A C6 21 49% 82% 63%
6 57 M 172 63 21.3 FFH A C5 33 38% 96% 60%
7 49 M 182 81 24.5 FFH B C4 40 44% 105% 53%
8 38 F 158 60 24.0 TA B C7 37 42% 99% 72%
9 42 M 175 64 20.9 CI A C5 53 41% 95% 64%
10 53 M 177 73 23.3 TA B C6 49 43% 93% 81%
11 62 M 174 65 21.5 FFH A C6 29 50% 87% 60%
12 27 F 166 57 20.7 TA A C5 43 40% 93% 64%
13 36 F 160 55 21.5 FFH B C7 21 53% 96% 75%
14 48 M 173 74 24.7 FFH B C4 52 39% 101% 50%
15 55 M 178 79 24.9 FFH A C5 33 48% 97% 62%
16 64 M 171 65 22.2 GIF B C5 37 42% 86% 66%
17 20 M 180 77 23.8 FFH A C5 19 48% 98% 70%
18 49 M 175 68 22.2 FFH A C6 36 45% 83% 64%
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SP study participants, M male, F female, BMI body mass index, IM injury mechanisms, TA traffic accidents, FFH falls from height, GIF ground-level falls, CI crush injuries, AIS American Spinal Injury Association impairment scale, NP neural plane, TSI time since injury.

CPET outcomes during FES-cycling exercise

Significant temporal variations were observed across all cardiopulmonary parameters during FES-cycling exercise: VE (F = 89.46, P < 0.0001), VT (F = 17.25, P < 0.0001), SBP (F = 52.12, P < 0.0001), DBP (F = 15.05, P < 0.0001), HR (F = 68.25, P < 0.0001), VO2 (F = 109.5, P < 0.0001), O2 pulse (F = 47.46, P < 0.0001).VE, SBP, DBP, HR, VO2, and O2 pulse demonstrated concordant trends with incremental FES-cycling exercise cadence (Fig. 2A, C–G), reflecting progressive activation of aerobic metabolism and cardiopulmonary systems under increasing exercise intensity. Pairwise comparisons revealed statistically significant inter-phase differences (P < 0.05) for VE, VO2, and O2 pulse throughout the protocol. In contrast, VT exhibited discordant dynamics relative to cadence(Fig. 2B), with transient reductions observed at 4- and 10-minute intervals compared to preceding phases. However, these decreases failed to reach statistical significance (P > 0.05).

Fig. 2.

Fig. 2

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CPET outcomes during FES-cycling exercise. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.

Discussion

In the present study, we observed that individuals with subacute phase traumatic motor-complete CSCI exhibit significant acute cardiorespiratory physiological responses to FES-cycling exercise in the recumbent position. It is well established that high-level SCI leads to severe multisystem dysfunction, affecting motor, autonomic, and respiratory systems. The SCI-induced loss of sympathetic control over the spinal cord results in a rapid and sustained decline in cardiac function8, as well as a swift reduction in muscle mass below the level of the lesion27. Consequently, early rehabilitation intervention is critical for individuals with high-level spinal cord injuries. Despite this, most current research on the application of FES cycling for SCI patients is conducted during the chronic phase.

Furthermore, there is variability in the definition and timing of the subacute phase of SCI, which, from a pathophysiological perspective, is considered to span from a few days to several weeks post-injury28. The European multicenter study on SCI delineated the acute phase as the first 15 days post-injury and the subacute phase as extending from 16 days to 6 months post-injury29. In contrast, the acute and subacute phases for SCI rehabilitation have been defined as encompassing up to 12 months post-injury30. However, research by Fawcett et al. indicates that the majority of functional recovery in motor-complete SCI occurs within the first 3 months31. This finding significantly influenced our decision to include participants in our study who had sustained a SCI less than three months prior.

Our static pulmonary function evaluations identified a consistent pattern of restrictive ventilatory dysfunction among the participants, with FVC%pred values ranging from 38 to 53% of predicted norms. Notably, 22.2% of the participants also exhibited obstructive ventilatory patterns, while 77.8% showed reduced ventilatory reserve, aligning with previous findings of decreased lung volumes and diffusion capacity in patients with injuries above the T6 level32. Individuals with CSCI typically present with FVC and FEV1 values below 50% of predicted levels33. This respiratory compromise primarily arises from dysfunction of the diaphragmatic and intercostal muscles, leading to diminished respiratory drive, reduced pulmonary compliance, and restrictive ventilatory impairment. The pathophysiological triad of impaired innervation of respiratory muscles, decreased lung volumes, and altered chest wall mechanics collectively contributes to this restrictive pattern.

Additionally, a subset of patients develops superimposed obstructive components due to autonomic nervous system dysfunction of bronchomotor tone, characterized by impaired sympathetic regulation and unopposed parasympathetic dominance, along with ineffective cough mechanics resulting from abdominal muscle paralysis. This dual pathology presents as a mixed ventilatory disorder, characterized by both restrictive and obstructive physiological parameters34. The existing literature reports altered ventilatory patterns during arm ergometry in patients with CSCI, marked by reduced VT, compensatory tachypnea, and decreased aerobic capacity35. Our findings expand this paradigm to include FES-cycling exercise: progressive increases in cadence resulted in corresponding increases in VE and VO2, indicating that FES-induced skeletal muscle activation enhances aerobic metabolic demand and stimulates ventilatory drive. Gorgey et al. also observed that the acute response of subjects with complete SCI to FES cycling was characterized by a significant increase in VE and a significant decrease in the ventilation-to-carbon dioxide ratio36. However, the observed reduction in VT at higher exercise intensities, coupled with respiratory muscle fatigue, may impose physiological limits on achievable exercise workloads, which is a critical consideration for exercise training prescription37. Although acute FES-cycling exercise in our cohort did not reach VO₂ levels comparable to those achieved through moderate-vigorous aerobic training in neurologically intact individuals, emerging evidence indicates potential longitudinal benefits. A recent multimodal MRI study demonstrated that a 6-month regimen of low-intensity FES-cycling exercise led to increased muscle volume and reduced intermuscular fat infiltration in patients with complete SCI38. Further evidence from longitudinal intervention studies suggests that FES-cycling exercise programs enhance functional independence, motor performance, and FVC in individuals with chronic SCI39. Schleifer et al. propose that hybrid FES is an effective method for improving maximum VO2 and increasing the anaerobic threshold (AT) in SCI patients. Additionally, it is crucial to commence exercise training as soon as possible following injury to maximize benefits40. These findings imply that sustained FES-cycling exercise regimens may optimize ventilatory-metabolic coupling during physical exertion through neurophysiological adaptations. However, further research is needed to explore long-term interventions for populations in the subacute stage of SCI.

The cardiovascular sequelae associated with subacute CSCI merit thorough investigation. The present cohort exhibited remarkably diminished resting HR and BP, which are hallmarks of sympathetic cardiovascular dysregulation. Concurrently, studies have demonstrated that individuals with CSCI exhibit a substantial decline in resting arterial BP and HR when in a seated position, in comparison to those with thoracic SCI and to individuals who are non-disabled41. This is a pivotal factor in the selection of recumbent FES-cycling exercise. During recumbent FES-cycling exercise, incremental increases in cadence prompted compensatory elevations in HR, blood pressure, and O2 pulse. This observation suggests that recumbent positioning facilitates venous return, despite the compromised sympathetic-mediated peripheral vasoconstriction. Concurrently, the exercise induced by FES results in a compensatory rise in both HR and per-pulse output, which may elucidate the underlying mechanism for the observed increase in SBP. Existing literature supports these findings, indicating that passive lower limb cycling in individuals with CSCI enhances blood pressure, cardiac output, and endothelial function through improved muscle pump activity and venous return42. Despite the evidence from CPET results indicating that peak VO2 levels achieved during upright cycling exceed those achieved during recumbent cycling, both in healthy individuals and those with cardiopulmonary disease43, there is currently a paucity of research on the acute cardiopulmonary physiological response to recumbent FES-cycling exercise in individuals with CSCI. Our research results show that supine FES-cycling exercise can improve VO2 and O2 pulse in CSCI individuals.

Furthermore, research across varying levels of impairment has demonstrated that lower limb FES significantly enhances VO2 in individuals with tetraplegia and paraplegia, as well as increases cardiac output in those with tetraplegia44. Notably, lower limb exercise driven by FES exhibits superior hemodynamic responses compared to upper limb ergometry, likely due to the greater activation of the venous capacitance bed in the lower extremities45. In contrast to FES upper limb hand cycling, individuals with spinal cord injuries above the T6 level achieve higher peak oxygen consumption during mixed cycling46. However, longitudinal studies have documented progressive left ventricular atrophy and systolic dysfunction in patients with CSCI during the 3–6 month post-injury period, which remain unaffected by subacute FES training—a deterioration not observed in thoracolumbar SCI cohorts47,48. These conflicting findings underscore the necessity for further research into the cardiovascular adaptations associated with FES-cycling exercise in individuals with motor-complete SCI.

The safety of early FES-cycling exercise intervention for participants with subacute CSCI was a primary concern throughout this study. It is crucial to assess the safety of FES-cycling exercise interventions in this population, as individuals with spinal cord injuries at or above the T6 level may experience uninhibited sympathetic reflexes in response to injurious stimuli, potentially resulting in a significant increase in blood pressure accompanied by symptoms such as headache, facial flushing, sweating, and bradycardia49. Moreover, case studies have documented the occurrence of AD during cardiorespiratory exercise testing using seated handcycles50. Therefore, to mitigate the risk of AD, primary triggers were addressed before initiating the FES-cycling exercise. This included ensuring bladder and bowel evacuation and inspecting participants for any skin breakdown.

Additionally, participants’ blood pressure and symptoms were closely monitored throughout the testing period. In this study, only one participant experienced an increase in SBP exceeding 20 mmHg from baseline (120 mmHg compared to 97 mmHg) but did not exhibit any concurrent symptoms of AD. Research conducted on small populations has also concluded that FES-cycling exercise in people with high-level spinal cord injuries is safe and may even reduce the risk of AD51,52.

Limitations of the study

The present study is subject to several significant limitations. Foremost, the stringent inclusion and exclusion criteria, which focused on individuals with subacute traumatic CSCI within three months post-injury, resulted in a constrained sample size. This limitation may impact the generalizability of the findings. Methodologically, although the study utilized an incremental exercise protocol through FES-cycling exercise with comprehensive monitoring of cardiovascular, respiratory, and gas metabolic parameters during CPET, it did not conform to standard symptom-limited CPET protocols. Additionally, the normalization of VO2 values to total body weight may have compromised the accuracy of metabolic assessments, given the typical body composition changes in SCI populations, characterized by skeletal muscle atrophy and increased adiposity53. Future research should consider correcting for lean body mass to achieve more precise physiological interpretations. Furthermore, the current study concentrated on acute physiological responses, leaving the longitudinal effects of FES-cycling training on cardiometabolic adaptations and body composition in this population to be explored through extended intervention studies.

Conclusion

The findings of this study demonstrate that FES-cycling exercise elicits a range of acute cardiopulmonary physiological responses in individuals with subacute traumatic motor-complete CSCI. The aforementioned responses encompass an augmentation in VE, VT, and VO2, concomitant with an escalation in HR, O2 pulse, and BP. Nonetheless, it is crucial to acknowledge that individuals with cervical spinal cord injuries frequently exhibit restrictive or mixed ventilatory dysfunction. Although VE increases with escalating exercise intensity, VT diminishes at higher exercise loads, resulting in an accelerated respiratory rate. Engaging in prolonged exercise may result in shortness of breath. Additionally, despite the absence of adverse reactions, such as AD, during the study, continuous monitoring of individuals with subacute CSCI is essential during FES-cycling exercise to ensure their safety.

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary Material 1 (14.8KB, xlsx)

Acknowledgements

The authors appreciate the time and effort of all participants.

Author contributions

ZG conceived the experiment and wrote the manuscript, YM supervised and quality controlled the trial, SW conducted the experiment, ZZ analysed the results and proofread the manuscript. All authors reviewed the manuscript.

Funding

This work was supported by the Zhejiang Province Medicine and Health Science and Technology Program (No. 2023KY857) and“Sanying” Talent Training Project (3.0) of the First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Chinese Medicine).

Data availability

Data is provided within the manuscript or supplementary information files.

Declarations

Competing interests

The authors declare no competing interests.

Ethical approval

This study was approved by the First Affiliated Hospital of Zhejiang Chinese Medical University Ethics Committee (Approval No. 2023-KLS-113-01). Informed consent was obtained to publish clinical data of the patient(s) / participants in the study.

Clinical trial

The clinical trial described in this paper was registered at the Medical Research Registration and Filing Information System(https://www.medicalresearch.org.cn) under the registration number MR-33-24-032280.

Footnotes

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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