The Study Of Tollip Gene Deletion Aggravated Pressure Over-load Induced Cardiac Hypertrophy In Mice

Aims: We bulid pressure over-load induced cardiac hypertrophy animal model by aortic bandingoperation in wild-type mice and Tollip gene knock out mice to investigate the potential effectofTollip in cardiac hypertrophy.Methods: We selected male C57BL/6mice (Wild Type) and Tollip gene knockout mice(Tollip KO, C57BL/6background) with age from8to10weeks old and weight from23.50g to27.5g for our experiments. All mice were seperated into two groups, which weresubjected to aortic banding(AB) and Sham sugery(SHAM). After4weeks, we performedechocardiography and hemodynamic to assess interventricular thickness and cardiacfunction. We dissected the hearts and the lungs, and weighed to compare the heartweight/body weight（HW/BW）, heart weight/tibia length（HW/TL）and lung weight/bodyweight LW/BW） ratios. Pathological examination were performed to observecross-sectional area of cardiac myoctes, cardiac interstitial and perivascular collagen fibrils.Real-time Real Time-PCR was used to detected the mRNA levels of cardiac hypertrophicmarkes(ANP、BNP、β-MHC) and cardiac fibrosis markers(CollagenIα、CollagenⅢ、CTGF).Western blotting detected the protein levels of signaling pathway molecules.Co-immunoprecipitation detected the interaction of proteins.Results: In pressure over-load induced cardiac hypertrophy animal model, compared withWT mice, Tollip gene KO mice showed as follows:1.Cardiac hypertrophy increased: Heartweight gained, HW/BW、HW/TL and LW/BW ratios increased. Cross-sectional area andsize of cardiac myoctes increased.2.Cardiac function decreased: EF, FS, dp/dt maxanddp/dt min decreased, thickness of ventricular wall increased.3.Cardiac fibrosisincreased: interstitial fibrosis and perivscular fibrsis up-regulated, associated with increasesof mRNA expression of fibrotic markers.4. Signaling pathway changed: thephosphorylation levels of AKT and its downstream genes GSK3β involed in hypertrophicsignaling pathway up-regulated in heart. In HEK293T cells, Tollip interacted with akt.Conclusions: Tollip attenuated cardiac hypertrophy, fibrosis and dysfuction, becauseTollip interacted with AKT to inhibited activation of AKT-GSK3β signaling pathway...