Effect of captopril on vWF in radiation renal injury

Objective: To explore the effect of captopril on plasma and glomerular vWF in radiation renal injury. Methods: A total of 96 male SD rats weighing 280-300 g were randomly divided into three groups: control group(n = 20), radiation alone group(n = 38), captopril + radiation group(n = 38). The latter two groups were subjected to a single-dose of 12 Gy 5 MeV electron rays to the kidneys. The captopril + radiation group began to receive captopril at the concentration of 0.38-0.50 mg/ml at 24 h before irradiation. The blood and urine samples were collected in the radiation alone and captopril + radiation groups at 48 h, 1, 2, 4, 8, 16, 24 weeks after irradiation (six rats per time in each group). Except for the 2 weeks after irradiation, kidneys were removed in the two groups at other point in time(six rats per time in each group). The kidneys, blood and urine samples were collected in the control group at 48 h, 4, 24 weeks after irradiation (six rats per time in each group). The glomerular vWF was detected by immunohistochemistry, collagen deposition in glomeruli by Sirius Red F3B in saturated carbazotic acid stain and plasma vWF and cystatin C levels by ELISA. Roche biochemical automatic analyzer and roche specific reagent were used to examine urine protein and urine creatinine, and urine protein clearance by urine protein and urine creatinine were calculated. The renal morphological feature was observed under light microscope after HE staining. Results: In radiation alone group, glomerulus vWF increased gradually at 16 and 24 weeks after irradiation(t = 3.53-6.95, 5.71-12.66, P < 0.05), collagen deposition in glomerular also gradually increased at 8, 16 and 24 weeks after irradiation(t = 3.03-5.13, 3.48-4.68, 4.68-9.03, P < 0.05), and there was an obvious positive correlation between collagen and vWF (r = 0.819, P < 0.05). There was an increase in plasma vWF at 2, 4 and 16 weeks after irradiation (t = 3.93-5.03, 4.04-5.15, 3.48-4.58, P < 0.05), plasma cystatin-C (t = 5.10-6.17, P < 0.05) and urinary protein clearance(t = 14.59-16.34, P < 0.05) at 24 weeks after irradiation, and the pathological changes of kidney were mild mesangial proliferation at 24 weeks after irradiation. In captopril + radiation group, captopril failed to decrease plasma vWF at 2 weeks after irradiation (P > 0.05). Except for that, captopril reduced glomerulus vWF(F = 15.60, t = 9.82, P < 0.05), collagen deposition in glomerular (F = 10.24, 16.08,t = 8.63, P < 0.05), plasma vWF (t = 3.77, P < 0.05; F = 4.16, P < 0.05), plasma cystatin-C (t = 6.68, P < 0.05) and urinary protein clearance(t = 13.01, P < 0.05), and obvious renal pathological changes were not observed in captopril + radiation group. Conclusions: Captopril can reduce plasma and the glomerulus vWF in radiation renal injury, and effectively protect the kidney. (authors)