Abstract:

Zheng Yunpeng, Chen Xu*, Huang Dan, Xu Song, Gu Heng. *Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College; Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing 210042, China Corresponding authors: Gu Heng, Email: guheng@aliyun.com; Chen Xu, Email: doctor_chx@126.com 【Abstract】 Objective To evaluate the effects of alpha-lipoic acid （α-LA） on autophagy in human skin fibroblasts （HSFs）. Methods HSFs at passage 3 － 5 were divided into several groups to be cultured with α-LA at final concentrations of 0, 0.01, 0.05, 0.10, 0.15, 0.20 and 0.50 mmol/L for 4, 12 and 24 hours, respectively. Methyl thiazolyl tetrazolium （MTT） assay was performed to evaluate cellular proliferative activity, monodansylcadaverin （MDC） staining to determine autophagy levels, and Western blot to measure the expression of the microtubule-associated protein 1 light chain-3B （LC3-B）. Results After incubation for 24 hours, there was a significant difference in the proliferative activity of HSFs among all the groups （F = 10.41, P < 0.05）, while no significant differences were observed after incubation for either 4 or 12 hours （F = 2.85, 1.34, respectively, both P > 0.05）. MDC staining also showed a significant difference in the percentage of autophagosome-positive cells among all the groups after 24-hour incubation （F = 8.03, P < 0.05）, but no significant difference after either 4- or 12-hour incubation （F = 0.11, 0.10, respectively, both P > 0.05）. Western blot revealed that the degree of conversion from LC3-Ⅰ to LC3-Ⅱ（LC3-Ⅱ/LC3-Ⅰratio） was significantly different among all the groups after 24-hour incubation （F = 37.49, P < 0.05）, but similar after 4- and 12-hour incubation （F = 3.38, 2.13, respectively, both P > 0.05）. Conclusion α-LA may inhibit basal autophagy in HSFs.