Table 1. Original publications on infrared thermography (IRT) associated with pain in laboratory animals.

Laboratory species	Category	Contribution	Author(s)
Rat	Infrared thermography as a support tool for monitoring human health	Demonstrated the usefulness of thermography (even in anesthetized animals) and that related experiments (rat model of neuropathic pain) can contribute to our understanding of the role of alterations of skin temperature and sympathetic activity in the pathogenesis of neuropathic pain in humans.	[47]
Rat	Infrared thermography as a support tool for monitoring human health	Administration of SJHXT (a mixture of 17 herbal plants) in an arthritis model in rats (chronic pain). An increase in the temperature of the surface of the tail appeared to improve peripheral circulation. Increased locomotor activity is attributable to the elimination of pain.	[48]
Rat	Infrared thermography as a support tool for monitoring human health	Rats with transection of the tibial and sural nerve (TST) showed behaviors characteristic of neuropathic pain. Resistance to bilateral surgical sympathectomy was observed. Hence, the TST model can be a useful, easily reproducible model of sympathetically independent pain (SIP).	[49]
Mouse	Infrared thermography as a support tool for monitoring human health	Demonstrated that while a surgical incision does not cause hyperalgesia due to cold, it does cause inflammation and an increase in temperature. This suggests that distinct mechanisms are involved in surgical inflammatory pain.	[50]
Pig	Infrared thermography as a support tool for monitoring animal health(Validating the use of thermography)	Determined the emissivity of adult pig skin from the shoulder, the base of the ear, and the caudal part of the udder, as well as the effect of the villus on blood perfusion in emissivity.	[51]
Pig	Infrared thermography as a support tool for monitoring human health (Validating the use of thermography)	This study demonstrated the capacity of infrared thermography for monitoring the control of circulation and blood perfusion in a swine animal model (systemic inflammatory response syndrome [SIRS] or sepsis).Developed indices to quantify the course and severity of the disease.	[52]
Rat	Analgesic action	Modulation of the temperature of damaged tissue (model of a partial lesion of the Achilles tendon in rats). Offers evidence of the participation of LLLT (low-level laser therapy) in controlling these inflammatory agents, since the mediators are directly involved in fostering a temperature increase in the tissues at the site of the injury.	[53]
Mouse	Evaluating the welfare of rodents	The use of thermographic images can contribute to refining studies with animals, basically by monitoring the respiratory frequency and locomotor activity that contribute to the detection of stress or pain.	[54]
Pig	Evaluating the welfare of piglets	Shows the capacity of infrared thermography to precisely measure cardiorespiratory signals in anesthetized piglets, in which an increase in heart rate and respiratory frequency (RF) may be associated with pain, fear, anxiety, and panic.	[55]
Mouse	Analgesic management of painEvaluating the welfare of rodents	Evaluated acute surgical pain in a mouse model of a spinal cord lesion (LSC) using the Mouse Grimace Scale infrared thermography, and administration of multimodal analgesia with buprenorphine (opioid + AINE) and carprofen vs. buprenorphine. The former was more effective.	[56]