OBJECTIVETo investigate the effects of spironolactone on the concentration of collagen type I, III in the myocardium of spontaneous hypertension rats (SHR).

METHODSTwenty 8-week male SHR were assigned randomly into spironolactone (SHR-SPIRO, n=10) and control groups (SHR-CON, n=10), sex-age matched Wistar Kyoto rats (WKY group, n=7) were also served as controls. The rats of SHR-SPIRO group were given 20 mg/(kg*d) of spironolactone, the rats of SHR-CON and WKY groups were given the same volume of distilled water. After 16 weeks, the concentration of collagen type I was analyzed with Western blot. The areas of collagen type I and III were observed under polarized light microscopy and the ratio of type I/III collagen was calculated through accumulation score.

RESULTSCompared with WKY group,the concentration of collagen type I in SHR-CON group was significantly higher (1.87 ±0.2 Compared with 1.21 ±0.7, P<0.05). After 16 weeks of treatment the concentration of collagen type I (1.42 ±0.05 Compared with 1.87 ±0.2, P<0.05) and I/III ratio in SHR-SPIRO group were significantly reduced (15.64 ±1.34 Compared with 20.8 ±3.04, P<0.05) compared with SHR-CON group; but there were no differences in accumulation area scores of collagen type III among three groups (368.3 ±30.2 Compared with 481.6 ±32.4 Compared with 406.2 ±45.3, P>0.05).

CONCLUSIONThe deposition of collagen type I in myocardium may be involved in myocardial fibrosis of SHR, and spironolactone can decrease the concentration of collagen type I, which may be one of the mechanisms for its therapeutic effects.

Animals ; Collagen Type I ; metabolism ; Collagen Type III ; metabolism ; Male ; Mineralocorticoid Receptor Antagonists ; pharmacology ; Myocardium ; metabolism ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Spironolactone ; pharmacology

ed in vitro and in vivo,which was inhibited by aspirin treatment.