Establishment of scald-induced pain model in rats: a constant-temperature electrical scald instrument / 中华麻醉学杂志

ABSTRACT

Objective To establish a scald-induced pain model using a constant-temperature electrical scald instrument in rats.Methods Thirty-six pathogen-free male Sprague-Dawley rats, weighing 200-250 g, were randomly divided into 4 groups (n =9 each) using a random number table control group (group C), scald for 5 s group (group S5), scald for 10 s group (group S10), and scald for 15 s group (group S15).The rats were anesthetized with intraperitoneal chloral hydrate.In S5, S10 and S15 groups, the plantar surface of the left hindpaw of rats were exposed to a constant-temperature electrical scald instrument (85 ℃) for 5, 10 and 15 s, respectively.The plantar surface of the left hindpaw of rats was exposed to an electrical scald instrument (room temperature) for 10 s in group C.At 1 day before treatment (T0),and 1, 3, 5, 7 and 14 days after treatment (T1-5), the mechanical and thermal pain thresholds were measured.Immediately after treatment, and at 24 h after treatment, the total body condition, wound color, and shape of the margin of the wound were observed and recorded.At 24 h after treatment, 3 rats were randomly sacrificed, and the skin from the plantar surface of the left hindpaw was removed for microscopic examination.Results Compared with group C, the thermal pain threshold at T1-2, and the mechanical pain threshold at T1-3 were significantly decreased in group S5, and the thermal pain threshold,and mechanical pain threshold were significantly decreased at T1-4 in group S10 (P＜0.05).The thermal pain threshold ＞ 25 s, and the mechanical pain threshold ＞30 g at T1-5 in group S15.The swelling in foot was bovious, burn blister appeared, and the degree of damage was aggravated in group S10 compared with S5 and S15 groups.Conclusion The scald-induced pain model is successfully established using a constant-temperature electrical scald instrument in rats.