Ethanol Intervention In Diabetic Myocardial Fibrosis And The Role Of Wnt/β-catenin Signaling Pathway

Objective:Changes of myocardial fibrosis in diabetic rats was studied, and ethanol intervention in myocardial fibrosis and the role of wnt/β-catenin signaling pathway was also investigated.Methods::Male SD rats were divided randomly into3groups (n=8):(1) Control group:fed a normal diet for8weeks;(2) Diabetes group:diabetes mellitus rat model was induced by intraperitoneal injection of STZ at a dose of55mg/kg for8weeks;(3) Ethanol intervention group:After diabetic model was succeeded for1week, the drinking water was replaced with2.5%ethanol, normal feed for1week, then changed to5%ethanol until8th week. Fast blood glucose level in plasma was measured; heart weight/body weight ratio and hydroxyproline content in myocardium were measured; The levels of ALDH2mRNA, Col I and ColIII mRNA were measured by reverse transcriptase polymerase chain reaction (RT-PCR); the expressions of β-catenin and wisp-1in myocardial tissue were measured by immunohistochemical method.Results:(1) Plasma blood glucose level:the levels of plasma blood glucose in diabetes group and ethanol intervention group were significantly higher than that in control group (p<0.01), but there was no significant difference between diabetes group and ethanol intervention group.(2) Heart weight/body weight ratio:compared with control group, the ratio was increased obviously in diabetes and ethanol intervention groups (p<0.01); compared with diabetic group, the ratio was reduced in ethanol intervention group (p<0.01).(3) Hydroxyproline content in myocardial tissue:compared with diabetic group, hydroxyproline content was markedly increased in diabetes and ethanol intervention groups (p<0.01), compared with diabetes group, hydroxyproline content was reduced in ethanol intervention group (p<0.01).(4) Electron microscope detection: myocardial myofibril and sarcomere in neat mitochondria membrane was integrity and no swelling, mitochondrial cristae was clear and arranged regularly in control group. In DM group, mitochondria was swelling, myocardial myofibril was arranged irregularly, sarcomere was fractured. And mitochondrial membrane was not integrity, mitochondrial cristae was disappeared, cavitation bubble was formed. In ethanol intervention group, mitochondrial membrane was swelling and incomplete, mitochondrial cristae was ruptured and disappearance, there was cavitation bubble.(5) The levels of ALDH2mRNA, Col I and ColIII mRNA by RT-PCR:compared with control group, ALDH2mRNA level was reduced in diabetes group(p<0.01), Col I mRNA level was increased and ColIII mRNA level was reduced(p<0.01), the ratio of Col I/ColIII was increased(p<0.01); compared with diabetes group, in ethanol intervention group, ALDH2mRNA level was increased(p<0.01), Col I mRNA level was reduced and ColIII mRNA level was increased(p<0.05), the ratio of Col I/ColIII was decreased(p<0.01).(6) Immunohistochemical results:in diabetic and ethanol intervention groups, the expressions of β-catenin and wisp-1protein were higher than those in control group, compared with diabetic group, the expressions of β-catenin and wisp-1protein were reduced in ethanol intervention group.Conclusions:Ethanol can antagonize the happening of myocardial fibrosis in diabetes through excting ALDH2, down-regulation of β-catenin and its downstream target gene wisp-1in wnt signaling pathway maybe involved in the mechanism.