Melatonin pretreatment can improve the therapeutic effect of adipose-derived stem cells on CCl4-induced liver fibrosis

In this study, the therapeutic effect of Mel-incubated Adipose-derived mesenchymal stem cells (ADSCs) on CCl4-induced hepatic fibrosis was investigated. Mice with hepatic fibrosis were intraperitoneally injected with 8% CCl4 twice a week for 4 weeks. Starting from week 5, mice in the ADSC group and ADSC + Mel group were injected with 1 mL PBS cell suspension containing 1 x 10(6) ADSCs or ADSCs pretreated with 50 nM Mel twice a week for 2 consecutive weeks. Results: In the model group, severe histopathological changes were observed in the liver, including severe vacuolation, nuclear fragmentation, and liver fibrosis, and these changes were ameliorated by Mel-pretreated ADSCs. RT-qPCR results showed that Mel-induced ADSCs significantly inhibited the expression of proapoptotic genes (Caspase-8, Bax, and Caspase-3) and promoted the expression of an anti-apoptotic gene (Bcl-2). Immunohistochemical results showed that a large number of MMP-9-, TGF-beta-, and MMP-2-positive cells were present in the liver tissues of the model group, while the number of positive cells was reduced by Mel-induced ADSCs. ELISA results showed that the ADSC pretreated with Mel also significantly reduced the expression levels of TNF-alpha and IL-6. Conclusion: ADSCs pretreated with Mel significantly improved CCl4-induced liver fibrosis.