Experimental Study On The Dynamic Changes Of PI3K/Akt Signaling Pathway In Hepatic Stellate Cells After X-ray Irradiation

Objective: To investigate the relationship of PI3K/Akt signaling pathway with the activation of the hepatic stellate cells(HSC) and its role in radiation-induced hepatic fibrosis. Methods: HSC was treated with 6 MV X-ray irradiation together with the inhibitor of PI3K/Akt signaling pathway.The cells were divided into control group,inhibitor group, 10 Gy group, 10Gy+inhibitor group, 20 Gy group, 20Gy+inhibitor group and blank control group. MTT assay was conducted cell inhibition rate after 24、48、72and 96 hours.The cell apoptosis rate was detected by FCM. The expression of TGF-β1 in cell supernatants was detected by ELISA assay. The mRNA expression of α-SMA was detected by RT-PCR. The expression of p-Akt was detected by Western blot assay.Results: The normal growth of cells in the control group was observed, and the changes of cell morphology were more obvious with the increase of irradiation dose. MTT showed that the same effect time, with the increase in the dose of irradiation inhibition rate also increased(F=40.421,319.196,128.928,270.54,P<0.05). With the extension of time, the inhibition rate also increased. FCM showed that, compared with the control group, the apoptosis rate of the 10 and 20 Gy IR group increased with the increase of irradiation dose(t=8.43,11.63, P<0.05),The apoptosis rate decreased by the inhibitor of PI3K/Akt(t=8.09,4.89,P<0.05). ELISA, RT-PCR and Western blot assay showed that, compared with the control group, the differences of expression of inhibitor group, 10 Gy group,10Gy+inhibitor group and 20 Gy group, 20Gy+inhibitor group, the a-SMA, caspase-3 and caspase-9 with statistical significance(F=67.942,56.503,10.069,P<0.05). compared with the control group, the expression of TGF-β1, α-SMA and p-Akt also increased with the increase of irradiation dose in the 10 and 20 Gy group(t=6.91,7.80,9.28,P<0.05), but theywere declined by this inhibitor for both 10Gy(t=6.17,15.11,10.34,P<0.05)and 20Gy( t=10.04,6.85,23.84,P<0.05). Conclusion: X-ray irradiation could activate hepatic stellate cell through PI3K/Akt signaling pathways, which may further result in hepatic fibrosis. And inhibitor PI3K/Akt signaling pathway could decreased the hepatic fibrosis.