Effects Of Chronic Hypoxia And Monocrotaline On Left And Right Ventricular Function And The Expression Of Cardiac TRPC Channels In Rats

Objective: To discuss the function effects on left and right ventricles of rats in Chronichypoxia (CH) and monocrotaline (MCT) induced cardiac hypertrophy within3weeks,and the expression and pathophysiological significance of transient receptor potentialnormative (TRPC) family in both models of cardiac hypertrophy.Methods: The SD rats were randomly divided into control group (CON), chronichypoxia model group (CH) and Monocrotaline administration (MCT group). CHgroup, the rats were placed in chronic hypoxia (chronic hypoxia, CH,10%O2)environment rearing three weeks to induce pulmonary hypertension. MCT group, adose of50mg/kg (BW) MCT was given to SD rats by single intraperitoneal injection..In three models,We measured:①Right ventricular systolic pressure (RVSP), leftentricular systolic pressure (LVSP)，left and right ventricular pressure maximum rate ofrise (LV/RV+dp/dtmax), left and right ventricular pressure maximum rate of descent(LV/RV－dp/dtmax)；②Right ventricular mass index (RVMI)，left ventricular massindex (LVMI);③Left and right ventricular myocardium tissue sections were stained byHE and observed under light microscope;④Real-time polymerase chain reaction(Real-time-PCR) and were performed to detect the expression of TRPCsubfamily.⑤Western blot were performed to detect the expression of TRPC subfamilyprotein according to the RT-PCR results.Results: In comparison of the CON group:①RVSP and RVMI were markedly elevated(P<0.01), LVSP and did not change significantly,LVMI were markedly decreased (P <0.01) in CH group. RVSP and RVMI were markedly elevated (P<0.01), LVSP andLVMI did not change significantly in MCT group;②RV+dp/dtmaxwere markedlyelevated (P<0.01), RV-dp/dtmaxwere markedly decreased (P <0.01)，LV+dp/dtmax，LV-dp/dtmaxdid not change significantly in CH group. RV+dp/dtmaxwere markedlyelevated (P<0.01), RV-dp/dtmax were markedly decreased (P <0.01), LV+dp/dtmax，LV-dp/dtmaxdid not change significantly in MCT group;③Right ventricular myocardialfibers become thick, intracellular myofibrils increase in the number of disorderedarrangement of the myocardial fibers, the nuclei deeply stained, the shape of the nucleiis not regularity both in CH and MCT groups.Left ventricular myocardial fibers did notchange significantly in CH group;④There was significant difference in the levels ofmRNA and protein of TRPC1between CON and CH groups(P<0.05). There wassignificant difference in the levels of mRNA and protein of TRPC6between CON andMCT groups(P<0.05)；⑤There was significant difference in the levels of protein ofTRPC1between CON and CH groups(P<0.05), there was significant difference in thelevels of protein of TRPC6between CON and MCT groups(P<0.05).Conclusion:3weeks exposure to hypoxia could specifically induced:①SD ratssuffered right ventricular hypertrophy and the function of left ventricular was notsignificantly affected；②Raised the expression of mRNA and protein ofTRPC1channelin right ventricular. TRPC1may be involved in cardiac hypertrophy occurrence anddevelopment.3weeks injected MCT could induce:①SD rats suffered right ventricularhypertrophy, and the function of left ventricular was not significantly affected.②Raisedthe expression of mRNA and protein of TRPC6channel in right ventricular, TRPC6may be involved in the development of cardiac hypertrophy.This research provided pathophysiological reasons for using TRPC1and TRPC6astarget goals in the treatment of pulmonary heart disease.