TABLE 2.

Summary of TCT’s effect on CAP and their advantages and limitations.

Types of TCT	Operational principle	Representative method	The effect on CAP[ref]	Strengths	Limitations
Acupuncture	Stimulate the specific position of the human body	Zusanli (ST36); Hegu (LI4); Shenting (GV24); Baihui (GV20)	Stimulating vagus nerve of auricle or cutaneous branch inhibits inflammatory mediators produced by macrophages (da Silva and Dorsher, 2014)	Easy; safe; less toxic; side effects	Improper operation is easy to cause infection
TaVNS	Stimulate the auricular branch of vagus nerve	Non-invasive taVNS	TaVNS can increase efferent vagus nerve excitability by stimulating auricular points in the conchal region and increase the ACh release and activate CAP (Andersson and Tracey, 2012; Pavlov and Tracey, 2012; Kaczmarczyk et al., 2017)	Convenient; easy; non-traumatic	Need professional guide
Chinese herbal medicine	Oral administration (Chinese medicine Formula and Chinese patent medicine)	Berberine; Dandelion; Chinese medicine Formula (albizzia bark, nocturnal vine, lily, and Lanzhi); Chinese patent medicine (Coptis Chinensis and cinnamon)	Inhibiting the activity of acetylcholinesterase and increasing the level of ACh and the expression of a7nAChR, thus regulating CAP and inhibiting inflammation (Li et al., 2016; Wang et al., 2018b; Wang et al., 2019; Zhao et al., 2020; Yang et al., 2021)	Efficient; multitarget; safe	Need the guidance of a professional doctor; there is a high demand for the purity of the medicine

TaVNS, transcutaneous auricular vagal stimulation; ACh, acetylcholine; CAP, cholinergic anti-inflammatory pathway.