The Effect Of Cardiac Remodeling In Mice Induced By Insulin Resistance And Adiponectin Gene Knockout

Objective To observe whether wild-type mice and adiponectin knockout(APNKO)mice lead to cardiac remodeling,and whether cardiac remodeling is aggravated by lacking adiponectin(APN)and insulin resistence(IR).Method 16 wild-type C57 mice were randomly divided into Control and IR groups.16 APNKO mice were randomly divided into APNKO and APNKO+IR groups.The Control and APNKO groups were given normal diet,while other groups with a high-fat feed to induce insulin resistance.After 12 weeks,cholesterol(TC),triglycerides(TG)were measured by automatic biochemical analyzer,fasting plasma glucose(FPG)and fasting insulin(FINS)were measured by Elisa,and calculate HOMA-IR index.Heart weight(HW)and left ventricular weight(LVW)were measured,and the heart weight index(HWI)and the left ventricular weight index(LVWI)were calculated.The left ventricular myocardial were dyed by HE and Masson staining to observe the structure and the degree of myocardial fibrosis,and calculate collagen volume fraction(CVF)and Perivascular collagenvolume area(PVCA)to value the degree of perivascular fibrosis.The expression of matrix metalloproteinase-9(MMP-9),APN and adiponectin receptor1(Adipo R1)in myocardial were detected with immunohistochemical staining and Western Blot.Using real-time fluorescent quantitative PCR(RT-PCR)to measure the expression of myocardial APN and Adip R1 m RNA.in these indicators : HOMA-IR and FPG,FINS,serum adiponectin levels,the expression of myocardial Adipo R1 and MMP-9.The relationship between the expression of MMP-9 and FPG,FINS,serum adiponectin levels,HOMA-IR,the expression of myocardial APN and Adipo R1 were analysed by Pearson correlation.Results(1)There was no interactive effect between IR and APNKO on BW,HW,LVW,HWI,LVWI.There was interactive effect between IR and APNKO on FPG,FINS,HOMA-IR,CVF,PVCA,serum APN,and the expression of myocardial MMP-9,APN,and Adipo R1(P<0.05).(2)From HE staining,myocardial cell arranged order and limit boundary clear in Control group;myocardial cell arranged disorder in IR group and APNKO group;APNKO+IR group myocardial cell disorder degree aggravatingly,and the muscle fiber fracture were changed.(3)From Masson staining,compare Control group,CVF and PVCA were increased significantly in IR group and APNKO group.Compare IR and APNKO group,CVF and PVCA increased significantly in APNKO+IR group.(4)From immunohistochemical staining,the positive results in myocardial APN and Adipo R1 are brown,which distribute in cardiac cell membrane and cytoplasm.Compared Control group,the expression of myocardial APN and Adipo R1 decreased in IR group(P<0.05).Compared IR group,the expression of myocardial APN and Adipo R1 decreased(P<0.05)in APNKO group.The expression of myocardial APN and Adipo R1 decreased significantly in APNKO+IR group.The positive results in myocardial MMP-9 is brown,which distribute in cardiac cell membrane,cytoplasm and the stromal cellsaround blood vessels.Compared Control group,the expression of myocardial MMP-9 increased in IR group(P<0.05).Compared IR group,the expression of myocardial MMP-9 increased(P<0.05).The expression of myocardial MMP-9 increased significantly in APNKO+IR group.(5)From Western Blot,compared Control group,the expression of myocardial APN and Adipo R1 decreased(P<0.05)and MMP-9 increased in IR group(P<0.05).The expression of myocardial APN and Adipo R1 decreased(P<0.05)and MMP-9 increased in APNKO group(P<0.05).The expression of myocardial APN and Adipo R1 decreased significantly in APNKO+IR group and MMP-9 increased(P<0.05).(6)From RT-PCR,compared Control group,the expression of myocardial APN and Adipo R1 m RNA decreased in IR group(P<0.05).The expression of myocardial APN and Adipo R1 m RNA decreased in APNKO group(P<0.05).The expression of myocardial APN and Adipo R1 m RNA decreased significantly in APNKO+IR group.(7)With the analysis of Pearson correlation,it shows that myocardium MMP-9 was positively correlated with HOMA-IR(P<0.05),negatively correlated with serum APN,myocardium APN and Adipo R1(P<0.05).Conclusion The correlation between the level of adiponectin and the degree insulin resistance was proved to be negative.Both adiponectin knockout and insulin resistance could lead to cardiac remodeling synergistically.