AIM: To investigate the effect of losartan on the mRNA expression of type 2
angiotensin II
receptor and
cytokines in
diabetic rat kidney.METHODS: SD
rats were randomly divided by following groups: control rats(group C),diabetic rats(group D) and diabetic rats treated with losartan (30(mg·kg~(-1)·d~(-1)),by gavage,group DT).At the end of 8-weeks study,mRNA expressions of the type 2 angiotensin II receptor(AT_2),transforming growth factor-β_1(TGF-β_1),platelet-derived growth factor-B(PDGF-B),tumor necrosis factor-α(TNF-α) and collagen Ⅳ in rats
renal cortex were measured by RT-PCR,respectively.In addition,angiotensin Ⅱ level in renal cortex was determined by the radioimmunoassay.RESULTS: In group D,urine protein excretion(P<(0.01))and angiotensinⅡlevel(P<(0.05)) in rats renal cortex were increased obviously in contrast to group C.mRNA expressions of TGF-β_1,PDGF-B,TNF-α and collagen Ⅳ(P<(0.01))in diabetic renal cortex were markedly elevated in contrast to group C,too.However,mRNA expressions of AT_2 in group D showed a significant decrease(P<(0.05)).Administration of losartan markedly ameliorated urine protein excretion and mRNA expressions of TGF-β_1,PDGF-B,TNF-α and collagen Ⅳ(P<(0.05)),but increased AT_2 mRNA expression obviously in contrast to group D.CONCLUSION: The decreased mRNA expressions of AT_2 in diabetic kidney may be related with elevated mRNA expressions of TGF-β_1,PDGF-B,TNF-α and angiotensinⅡ.Down-regulation of renal cytokines expression may involve in the mechanisms of up-regulation expression of AT_2 caused by losartan.
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