Use of Water Immersion to Ameliorate the Progression of Chronic Experimental Kidney Disease
The possible benefits of aquatic environment to kidney function in renal failure stages not much been investigated. It is known that water environment could influence renal function positively: plasma renin activity is reduced, contributing to renal vascular pressure and sodium excretion. Water immersion causes increase in renal blood flow and contributes to the lowering in renal sympathetic nerve activity, renal vascular pressure and decrease in plasma renin activity. Non-swimming aerobic aquatic exercises have shown a beneficial effect to chronic kidney disease patients. We hypothesized that the aquatic environment could improve renal functioning and even slow the progression rate of chronic kidney disease (CKD). The aim of our study was to investigate the effects of regular water immersion and voluntary swimming to the rate of progression of experimental CKD. Wistar rats were divided into matched groups 2 weeks after 5/6 nephrectomy (5/6NPX) and studied during 18 weeks. One group was subjected to water immersion with water temperature 38o and swimming without exhaustion 30 min daily for 12 weeks. Control groups remained sedentary. Chronic studies of systolic blood pressure and urinary protein excretion rate (mg/24h) were performed. Renal morphology was studied and MCP-1 gene expression level was investigated in kidney tissue samples at the end of the study. The main systolic blood pressure was significantly lower and proteinuria was reduced significantly in the swimming-immersion group compared to control 5/6NPX animals. The degree of glomerulosclerosis and interstitial fibrosis was significantly less prominent in the water-therapy group. Expression of mRNA for chemokine MCP-1 in glomeruli of CKD animals differs significantly between the water-therapy group and control 5/6NPX group and was closely associated with effects on proteinuria and systolic blood pressure. These results point to the additional renoprotective properties of long-term water immersion and daily aquatic therapy in rats with CKD.