Pentoxifylline Supplement Ameliorated The Liver Function Of Aged Rats By Activated The Nrf2-ARE Signal Pathway

The aged liver is usually accompanied by morphological changes and the liver damage caused by lipid accumulation,fatty degeneration and liver fibrosis factors.Studies have shown that oxidative stress is one of the factors that cause organ changes and cell function declines in aging process.Oxidative stress damage to biological macromolecules,reduce the protein synthesis,increased cell apoptosis signal transduction,promote the degradation of protein.So,antioxidant may be caused by aging liver injury has certain improve defensive role.The nuclear factor E2-related factor 2(Nrf2)regulates the transcription of phase II enzymes through induction of the antioxidant-responsive element(ARE).The activation of Nrf2 up-regulated the expression of phase II enzymes,such as heme oxygenase-1(HO-1)and NAD(P)H:quinine oxidoreductase 1(NQO1),which plays a protective role on cell damage.Therefore,Nrf2-ARE way is one of the important antioxidant defense systems of the body.Activation of Nrf2-ARE way might be in the body has a protective effect.Pentoxifylline(PTX),as a non-specific phosphodiesterase inhibitor,is a modulator of a variety of transmitters.In recent years studies have shown that PTX also have antioxidant effect.However,PTX have protective effect to aging liver cells by activating Nrf2-ARE signal pathway which is not clear.Objective: To explore the effects of long-term PTX treatment on aging rat liver morphological structure and the liver function,and the mechanism of Nrf2-ARE signal pathway involved in antioxidant process.Methods: Male SD rats were randomly divided into three groups.6months of age group(6Mon,n=10),24 months of age group(24Mon,n=10)and 24 months of age following treatment with PTX group(24Mon-PTX,n=10).24Mon-PTX rats received intraperitoneal injection of PTX at the age of21 months.The dosage was 50mg/kg(dissolved in 0.9% saline).Once a day.The supplement of PTX continued for 12 weeks(84-day).6Mon and 24 Mon rats received 0.9% saline at the same time.5 rats in each group were used for HE stains and immunohistochemical analysis.The venous blood was collected for liver function index determination.Another 5 rats in each group were used for oxidative stress parameters assay,real-time fluorescence quantitative PCR and Western blot analysis.Results:1 HE staining results:The structure of rat liver cells was clear and complete in 6Mon rats.The liver cell morphological structure was fuzzy,liver cell hypertrophy,reducing the number,connective tissue hyperplasia in24 Mon rats.The morphological changes were improved significantly after long-term PTX treatment in 24Mon-PTX rats.2 Liver function results : Compared with 6Mon rats,alanine aminotransferase(ALT)(P<0.01),aspertate aminotransferase(AST)(P<0.01)and total bilirubin(TBiL)(P<0.01)significantly increased,albumin(ALb)significantly decreased(P<0.01)in 24 Mon rats.The above indicators improved significantly after long-term PTX treatment(P<0.01),but not reached the levels of 6Mon rats(P<0.01).3 Oxidative stress parameters results:Compared with 6Mon rats,liver malondialdehyde(MDA)level significantly increased(P<0.01),reduced glutathione(GSH)level decreased significantly(P<0.01)in 24 Mon rats.MDA was significantly reduced(P<0.01),GSH level increased significantly(P<0.01)after long-term PTX treatment,but not reached the levels of 6Mon rats(P<0.01).4 Real-time quantitative PCR detection results: Compared with 6Mon rats,liver Nrf2 mRNA,HO-1 mRNA and NQO1 mRNA expression significantly reduced(P<0.01)in 24 Mon rats.The above index expression increased significantly after long-term PTX treatment(P<0.01),but not reached the levels of 6Mon rats(P<0.01).5 Western blot test results: Compared with 6Mon rats,liver Nrf2,HO-1and NQO1 proteins expression significantly reduced(P<0.01)in 24 Mon rats.The above index expression increased significantly after long-term PTX treatment(P<0.01),but not reached the levels of 6Mon rats(P<0.01).6 Immunohistochemical detection results: Compared with 6Mon rats,the average optical density(AOD)of liver Nrf2,HO-1 and NQO1 significantly reduced(P<0.01)in 24 Mon rats.The above AOD of Nrf2,HO-1 and NQO1 increased significantly after long-term PTX treatment(P<0.01),but not reached the levels of 6Mon rats(P<0.01).Conclusion:1 Long-term PTX treatment improved the morphology of aging rat liver structure and liver function.2 Long-term PTX treatment improved the state of oxidative stress in the aging liver.3 Long-term PTX treatment activated the Nrf2-ARE antioxidant pathway.