MiR-122Expression And Its Significance In The Process Of Experimental Hepatocarcinogenesis In Rats

Objective:Observe the expression of miR-122in the process of experimental hepatocarcinogenesis in rats induced by diethyl nitrosamine and microcystin-LR. Investigate the significance of miR-122in hepatocellular carcinoma by analyzing the relationship between miR-122and AFP, P53, AD AM17.Methods:The75male SD rats were randomly divided into control group and model group, both of them were fed standard rat chow. The model group were used DEN and MC-LR for establishing rat model of hepatocellular carcinoma:intraperitoneal injection with0.25%DEN solution (10mg/kg) and MC-LR (20ug/kg) every five days, until to16weeks. HCC formation process can be divided into three phase,4weeks when induced is the period of liver cell damaged,8to12weeks is the period of liver cell proliferation-hardening and16to20weeks is the period of hepatocellular carcinoma. While the control group was coped with equal quantitative saline. Control group and model group at4weeks,8weeks,12weeks,16weeks,20weeks randomly selected5,10rats were killed, respectively. Then measure the weight of liver and body to get the liver body index; measuring each of ALT, y-GT, TBIL level via collecting orbital blood; analyzing liver tissue by histopathological examination; detecting the miR-122levels by qRT-PCR technology, quantitatively detecting the AFP, p53, AD AM17levels in liver tissues of8to20weeks with Western Blot techniqueResults:1. The model group were induced with DEN and MC-LR appearing cirrhosis at8to12weeks; successfully inducting hepatocellular carcinoma associated with cirrhosis after16weeks, the rate of cancer formation was5/7at16weeks, while6/6at20weeks, the overall mortality rate was10/30; rats in control group grew well with no abnormal death.2. The general condition of hepatocellular carcinoma model group:the LBI, ALT, y-GT and TBIL of model group is higher than the control group at various periods in the liver (P<0.05).3. MiR-122expression in HCC model:qRT-PCR analysis indicated that miR-122decline gradually in liver cancer at the process of induced, and there is a significant difference (P<0.05) in each period compared to the control group, but in cirrhosis period, there was no significant difference between8weeks and16weeks (P>0.05).4. The expression of AFP, p53, AD AM17in HCC tissue:Detecting at8to20weeks in liver tissue by Western Blot, AFP was increased in cirrhosis period, reaching a peak at20weeks, it is higher than the control group (P<0.05); the expression levels of P53, ADAM17at20weeks was significantly higher than the16weeks(P<0.05).Conclusion:1. Using MC-LR and DEN is an ideal way to induce hepatocellular carcinoma in rats, it has stability and security features.2. MiR-122in hepatocellular carcinoma induced by MC-LR and DEN in rats gradual decline during the various periods of process, it has a certain diagnostic value; and miR-122may be associated with the prognosis of liver cancer, the lower the expression, the worse the prognosis.3. MiR-122participate in regulating the downstream target genes P53, ADAM17, inhibiting its expression then inhibiting the cancer formation and metastasis. There are25figures,12tables and71references all in this thesis.