The effects of single and combined application of ramipril and losartan on renal structure and function in hypertensive rats

The objective of the present study was to investigate the effects of single and combined administration of ramipril and losartan on renal structure and function in spontaneously hypertensive rats (SHRs). Thirty-two 9-week-old SHRs and eight Wistar-Kyoto (WKY) rats were randomly divided into five groups: the WKY control group, the SHR control group, the SHR-ramipril group, the SHR-losartan group, and the SHR-combined mediation group. The rat body weight, SBP, heart rate, and urinary albumin excretion rate (UAER) were measured. (1) The SBP was reduced to the normal level in all groups of rats except for the SHR control group. Combined administration of ramipril and losartan can be reduced to the normal level earlier than single (P < 0.01). (2) The SHR-ramipril group and the SHR-losartan group still experienced a higher UAER than that in the WKY control group (P < 0.01). (3) The renal mass/BW ratio was decreased in the SHR-ramipril group, SHR-losartan group, and SHR-combined medication group compared to that in the SHR control group (P < 0.01). (4) Compared with the SHR control group, the SHR-ramipril group, the SHR-losartan group, and the SHR-combined medication group had a lower percentage of the IOD of glomerular collagen relative to the glomerular area (P < 0.01). (5) The reduction in tubulointerstitial injury score was more significant in the SHR-combined medication group than in the SHR-ramipril group and the SHR-losartan group (P < 0.01). The combination of ramipril and losartan is superior to either single drug in reducing the UAER, resisting glomerular collagen deposition, and protecting renal tubular structure.