Objective: To investigate the effect of melatonin (Mel) on the JAK2/STAT3 signaling pathway of hepatic stellate cell-T6 (HSC-T6) induced by platelet-derived growth factor (PDGF). Methods: HSC-T6 cells were divided into 6 groups: control group

model group

experimental groups (Mel 1 nmol/L

Mel 1 μmol/L

Mel 0.1 mmol/L) and inhibitor group (AG490 JAK2/STAT3 pathway inhibitor). Real-time fluorescent polymerase chain reaction (RT-PCR) was used to detect the mRNA expression of α-smooth muscle actin (α-SMA) and collagen typeⅠ (collagen-Ⅰ) in HSC-T6

and the protein expression detection of JAK-2

P-JAK2 and STAT3

P-STAT3 proteins in HSC-T6 cells was made by immunohistochemistry. Results: Compared with the control group

PDGF significantly activated the proliferation of HSC-T6

and significantly up-regulated the expression of α-SMA

collagen-ⅠmRNA and JAK-2

P-JAK2

STAT3 and P-STAT3 in HSC-T6.Compared with model group

Mel and JAK2/STAT3 pathway inhibitor inhibited PDGF induced HSC-T6 proliferation

and significantly down-regulated the expressions of α-SMA

collagen-ⅠmRNA and JAK-2

P-JAK2

STAT3 and P-STAT3.Conclusion: Mel can inhibit the activation and proliferation of HSC-T6 induced by PDGF

and the mechanism may be related to the inhibition of JAK2/STAT3 signaling pathway

which may be one of the mechanisms of melatonin improving liver fibrosis.