Amlodipine preserves the glomerular number in spontaneously hypertensive rats

Abstract

The calcium channel blockers have individual pharmacological and therapeutic properties that may vary, but as a group, they are effective antihypertensive agents in patients with renal disease. Their effects on the kidney may extend beyond BP reduction alone. Fifteen one-year-old male spontaneously hypertensive rats (SHR) were separated in three groups: Initial control group (IC), Final control group (FC, SHR received standard rat chow and fresh water ad libitum during 15 weeks), Amlodipine group (Aml, SHR) received 0.2 mg/kg/day of amlodipine in addition to food and water during 15 weeks. The glomerular number was estimated using the disector method. In the Control group, the BP level increased almost 20 per cent in the first six weeks (from 186 +/- 11 to 223 +/- 16 mmHg, p<0.01) and then BP level increased almost 15 percent until week 15 (from 223 +/- 16 to 258 +/- 20 mmHg, p<0.01). In the same period, the Aml group showed a progressively low BP, reaching a level almost 50 per cent lower in the week 15 than in the week 1 (from 190 +/- 15 to 101+/-8 mmHg, p<0.01). Amlodipine treatment significantly decreased the serum creatinine, more than 12 per cent lower than the FC group (from 70.4 +/- 6.2 to 61.4 +/- 5.2 micromol/L, p<0.05). However, proteinuria was not different when groups were compared. The FC group reached a glomerular number almost 20 percent smaller than the IC and Aml groups (from 35 x 10(3) +/- 7 x 10(3) in IC group, 34 x 10(3) +/- 4 x 10(3) in Aml group to 27 x 10(3) +/- 3 x 10(3) in FC group, p<0.05). A possible protective effect of amlodipine against the loss of glomeruli in SHR is a major additional action of amlodipine in the treatment of hypertension mainly when the renal lesion already exists.