Renal protection of rosiglitazone in hypertensive rats and its relationship with the expression of angiotensin Ⅱ receptors / 中华肾脏病杂志

ABSTRACT

Objective To observe the role of rosiglitazone in unclipped kidneys of two-kidney- one-clip hypertensive rats and examine its relationship to angiotensinⅡreceptors.Methods Two- kidney-one-clip hypertensive rats were divided randomly into 4 groups as followspositive control group (CONT),traditional antihypertensive drugs group (TAHD,reserpine 50?g?kg~(-1)?d~(-1), dihydralazine 6.25 mg?kg~(-1)?d~(-1) and hydrochlorothiazide 6.25 mg?kg~(-1)?d~(-1),regular-dose rosiglitazone group (RRGL,rosiglitazone 5 mg?kg~(-1)?d~(-1)),and high-dose rosiglitazone group (HRGL, rosiglitazone 20 mg?kg~(-1)?d~(-1)).Sham operation rats were as negative controls.Each group had 8 rats. Animals were monitored and sacrificed at 10th week.Results Blood systolic pressure in TAHD group and HRGL group was significantly lower than that in CONT group [TAHD(137?27 ) mm Hg and HRGL (143?16) mm Hg vs CONT (191?25 ) mm Hg,P＜0.05],but no significant difference between the former two groups was found.Nor did the blood systolic pressure between RRGL group [(176?18) mm Hg] and CONT group.At 10th week,rats in SHAM group and treated groups had lower urinary urinary protein excretion rate,glomerular injury score and wall-to-lumen ratio of arteriole than those in CONT group [vs CONT urinary protein excretion rate (44.60?17.40) mg/24 h,P＜0.05; vs CONT glomerular injury score 60.85?33.05,P＜0.05;vs CONT wall-to-lumen ratio of arteriole 2.33?1.01,P＜0.01,except TAHD group].Though with the similar level of blood pressure,blood glucose and lipid,HRGL,compared with TAHD group showed lower urinary protein excretion rate [HRGL (16.78?3.50) mg/24 h vs TAHD (27.94?12.79) mg/24 h,P＜0.05],decreased glomerular injury score (HRGL 18.04?7.76 vs TAHD 27.92?6.39,P＜0.05) and wall-to-lumen ratio of arteriole (HRGL 1.75?0.38 vs TAHD 2.16?0.90,P＜0.05) in the cortexes of unclipped right kidneys.The expression of type 1 angiotensinⅡreceptor (AT1R) mRNA was no difference in HRGL group and TAHD group,but the expression of type 2 angiotensinⅡreceptor (AT2R) mRNA was more intensive in HRGL group.Conclusion Rosiglitazone can protect the kidneys from hypertensive injury,especially in high dose.The beneficial effects seem incompletely dependent on the metabolism modulating and reduction of blood pressure,but in relationship to the upregulation of AT2R mRNA.