Changes of Rheb gene and protein expression in preeclampsia-like mouse model treated with pravastatin

Abstract

Objective: To explore whether pravastatin (Pra) inhibits mammalian target of rapamycin (mTOR) signal pathway by regulating Ras homolog enriched in brain (Rheb) protein through the comparison of gene and protein expression changes of Rheb in liver and placenta in preeclampsia (PE)-like mouse model treated with Pra. Methods: C57BL/6J pregnant mice were randomly divided into two groups. The PE group was established by injecting N-nitro-L-arginine methyl ester (L-NAME) daily at gestational 7-18 days, saline was injected as contol group (Con); then giving mice Pra (PE+Pra, Con+Pra group, n=8) or normal saline (PE+N, Con+N group, n=8) every day from the 8th gestational day of pregnancy. The maternal liver and placenta tissues were collected on the 18th day of pregnancy. Western blot, real-time quantitative PCR and immunohistochemistry were used to compare the levels of Rheb protein and mRNA expression in the liver and placenta. Results: (1)The results of western blot: there were no significant differences in Rheb protein expression between PE+N group (liver: 0.706±0.123; placenta: 0.866±0.128) and Con+N group (liver: 0.732±0.123; placenta: 0.909±0.097) , and the differences between PE+Pra group (liver: 0.669±0.134; placenta: 0.940±0.221) and PE+N group were not significant either in liver or in placenta (all P>0.05). (2) The results of real-time quantitative PCR: when PE+N group (liver: 1.026±0.480; placenta: 1.102±0.361) compared with Con+N group (liver: 1.058±0.389; placenta: 1.067±0.400) , PE+Pra group (liver: 0.735±0.356; placenta: 0.822±0.304) compared with PE+N group, there were no significant differences either in liver or in placenta (all P>0.05). (3) The results of immunohistochemistry: Rheb protein expression did not change significantly in maternal liver and placenta, there were no significant differences in protein expression levels between PE+N group and Con+N group, and between PE+Pra group and PE+N group (all P>0.05). Conclusion: The inhibition of Pra on mTOR signaling pathway in some PE-like model may be independent of the expression of Rheb gene and protein.