Effects of Intermittent Cold Exposure on Lipid Metabolism and mRNAs Expression of Brown Adipose Tissue Related Genes in Rats

CHEN Ling; YANG Shenghong; CHEN Suilin; HUANG Yiwen; WANG Yanyu; MA Wenjuan; RAN Jihua; SHI Qinghai

doi:10.13730/j.issn.2097-2148.2025.03.003

Abstract：Objective To establish a cold-acclimated rat model through intermittent cold exposure and explore the changes in blood lipid metabolism,brown adipose tissue proliferation and the expression of lipid metabolism related genes,and to analyze the regulatory role of brown adipose tissue.Methods A total of 53 male SD rats were divided into cold-acclimated group(n=30)and control group(n=23)by random number grouping method.In the cold-acclimated group,rats were exposed to 2-6 ℃ for 4 h lasting 21 d;rats in the control group were fed at room temperature.The rats in cold-acclimated group was weighed daily and their rectal temperature was monitored before and after cold expo-sure,while the rats in control group was weighed daily and their rectal temperature was measured same as cold-acclimated group.After 21 d,10 rats from the cold-acclimated group were removed for cold tolerance testing,and 20 were executed to collect blood and adipose tissues,of which 4 rats'brown adipose tissues were sequenced by transcriptome sequencing;6 rats from the control group were taken out for cold tolerance tests,and 17 rats were executed to collect blood and adi-pose tissues,of which 4 rats'brown adipose tissues were sequenced by transcriptome sequencing.Results The body mass and body mass gain of the cold-acclimated group were significantly lower than those of the control group at the 7th,14th and 21st days of intermittent cold exposure(P＜0.05),the difference in rectal temperature before and after cold exposure was gradually reduced,and the cold tolerance ability of-15 ℃ cold exposure was signifi-cantly higher than that of the control group(P＜0.001).The serum triglyceride and low density lipoprotein con-centration levels of rats in the cold-acclimated group were lower than those of the control group(P＜0.05),the white ad-ipose tissue mass was lower than that of the control group(P＜0.01),and the brown adipose mass was higher than that of the control group(P＜0.05).Transcrip tome sequencing analysis showed that there were 108 differential genes related to lipid metabolism in brown adipose tissues(P＜0.01),with 30 up-regulated and 78 down-regulated,affecting lipid syn-thesis,cholesterol metabolism,fatty acid transport,fatty acid metabolism and energy conversion and heat production,promotion of lipid droplet outgrowth respectively.Conclusion Rats with 21 d of intermittent cold exposure show im-proved cold tolerance,acquire cold acclimation,which enhance blood lipid utilization,likely through the promotion of brown adipose tissue proliferation and regulation of lipid metabolism-related gene pathways.