The Effects Of Ramipril On Renal Interstitial Fibrosis Of Chronic Heart Failure Rats

In the process of chronic heart failure gradually developed,usually accompany with renal injury,moreover renal damage can greatly exasperate the development of heart failure and seriously affect the prognosis of patients with heart failure,Therefore it is very important for the treatment and prognosis of heart failure patients to prevent or alleviate heart failure patients kidney damage.At present,angiotensin converting enzyme inhibitors(ACEI)is widely used in the treatment of heart disease,but it has been little applied to check the progress of renal interstitial fibrosis of heart failure rat.This experiment aims to explore the effects of ramipril,as an ACEI drugs,on renal fibrosis in rats with chronic heart failure.A large number of studies have shown that abnormal expression of platelet derived growth factor(PDGF)can promote the development of renal fibrosis by various ways.Occurrence and development of renal interstitial fibrosis is positive correlation of connective tissue growth factor(CTGF).Therefore we select CTGF and PDGF-B as observation target to investigate the effect of ramipril on renal fibrosis.In a word,intervention effects of ramipril in chronic heart failure rats can be evaluated by observing and comparing the pathologic change of kidney and the expression of PDGF-B and CTGF.Objective:To establish the rat model of chronic heart failure by constriction of abdominal aorta.To feed some rats on ramipril for four weeks after chronic heart failure models were established successfully.To observe nephridial histomorphology by HE staining and Masson staining method.By means of SP immunohistochemical method,to detect the expression quantity of CTGF and PDGF-B in the rats' renal tissue.To detect the expression level of CTGF m RNA and PDGF-B m RNA in the renal tissue of each rat by reverse transc-riptase PCR.To demonstrate the effects of ramipril on renal fibrosis and on the expression of platelet derived growth factor,connective tissue growth factor in renal tissues of rats with chronic heart failure.Methods:1 To purchase 40 male clean level Wistar rats and select 10 rats as the sham operation group after feeding of 6 days by the means of random allocation.The abdominal aorta of rats in the sham operation group were separated without ligation.The other 30 rats were used to establish the rat model with chronic heart failure by abdominal aorta coarctation.Left ventricular end diastolic pressure(LVEDP)?15mm Hg is model standard.To randomly select 10 rats as the model group and another 10 rats as the ramipril group after the models of chronic heart failure were eatablished successfully.2 To detect and record the hemodynamic index(left ventricular pressure maximum rate of rise and fall,LVEDP)by multi-lead electric physiological record instrument.3 To observe nephridial histomorphology changes by HE staining and Masson staining method.4 To detect the expression quantity of CTGF and PDGF-B in the rats' renal tissue by SP immunohistochemical staining.5 To detect the expression level of CTGF m RNA and PDGF-B m RNA in each rats' kidney by reverse transcriptase PCR.Results:1 To compare the rats' hemodynamic indexes in each groupThe LVEDP of sham operation group,model group,ramipril group was 5.16�0.18 mm Hg,19.39�0.35 mm Hg,11.23�0.30 mm Hg.Compared with the LVEDP of sham operation group,witch of model group obviously increased.The LVEDP of ramipril group was more than that of sham operation group,but which was far less than the LVEDP of model group,there were statistically significant differences between the groups(P<0.01).The +dp/dtmax of sham operation group,model group,ramipril group was 4346.62�174.29 mm Hg/s,2556.17�91.69 mm Hg/s,3248.91�55.08 mm Hg/s.The-dp/dtmax of the sham operation group,model group,ramipril group was 5555.15�60.70 mm Hg/s,4104.70�84.33 mm Hg/s,4850.96�76.14 mm Hg/s.The +dp/dtmax and-dp/dtmax of ramipril group were far less than those of sham operation group,but more than those of model group,differences were statistically significant(P<0.01).2 The nephridial histomorphology changes of each group2.1 HE stainingIn the sham operation group,kidney tissue structure of rats was clear,such as glomerular morphology was normal and epithelial cells arranged well without morphological changes;The kidney tissue of rats in model group was abnormal,renal tubular was obviously expansion and tubule-interstitial was significant broadening,in addition the renal tubular epithelial cells had a seriously disordered arrangement and staining obvious shallow;In the ramipril group,the renal tubular was only slightly expansion and tubule-interstitial was lightly broadening,moreover the arrangement of renal tubular epithelial cells became disordered.2.2 Masson stainingThere was very little collagen fibers deposition in the glomerulus and renal interstitium,in the sham operation group;In the model group,a large number of collagen fibers deposition could be seen in renal tubules and renal interstitial;A great deal of collagen fibers deposition in the renal interstitial;In the ramipril group,there was some collagen fibers deposition in the renal interstitial.Semiquantitative estimation of collagen showed that relative interstitial volume in the sham operation group,model group and ramipril group were 3.88�0.27%,32.94�1.76% and 11.21�0.82%.Relative interstitial volume in the ramipril group were higher than that of the sham operation group and significantly lower than the model group,difference between any two groups had statistical significance(P<0.01).3 The expression of CTFG protein and PDGF-B protein in each group3.1 The expression quantity of CTGF proteinIn the sham operation group,the expression of renal tissue in rats was negative;In the model group,the expression of renal interstitial and tubular epithelial cells was strong positive,when that of glomerulus was negative;In the ramipril group,the expression of renal interstitial and tubular epithelial cells was weak positive.There was a statistically significant diffrence between of two groups(P<0.01).3.2 The expression quantity of PDGF-B proteinIn the sham operation group,there was no obvious positive expression in nephridial tissue of rats;In the model group,there was a strong positive expression in the renal interstitial and tubular epithelial cells,however there was a negative expression in the glomerulus;In the ramipril group,there was a weak positive expression in renal interstitial and tubular epithelial cells of rats.There was a statistically significant diffrence between of two groups(P<0.01).4 The expression level of CTGF m RNA and PDGF-B m RNA4.1 The expression level of CTGF m RNAIn the sham operation group,it could be detected a low expression of CTGF m RNA in the kidney of rats.In the model group,CTGF m RNA expression in the kidney was obviously up-regulated.The expression of CTGF m RNA in the ramipril group was dramaticlly higher than that of the sham operation group,and notably lower than that of the model group.4.2 The expression level of PDGF-B m RNAThere was a low expression of PDGF-B m RNA in the kidney of rats,in the sham operation group.In the model group,PDGF-B m RNA expression in the kidney was notably up-regulated.The expression of PDGF-B m RNA in the ramipril group was dramatically lower than that of the model group,and obviously higher than that of the sham operation group.Conclusion:1 One of the renal pathological change in chronic heart failure rats was renal interstitial fibrosis.2 Ramipril can effectively prevent occurrence and development of renal interstitial fibrosis in rats with chronic heart failure.Down-regulation of CTGF,PDGF-B expression in the renal tissue may be relative to the formation of renal interstitial fibrosis.