Characteristics of purine metabolism in renal cortex during ischemia with subsequent reperfusion of one kidney (experimental study)

Partial nephrectomy is the standard to treat small kidney tumors. Post-hypoxic nephron damage is considered to be its unfavorable effect, leading to a disruption of functional activity. Purines are sensitive markers of tissue hypoxia. The purpose of the paper is to study purine dynamics and estimated coefficients in the renal cortex during 20-minute ischemia followed by renal reperfusion of one kidney in the experiment. Materials and Methods. The dynamics of adenine, guanine, xanthine, hypoxanthine, and uric acid (UA) in the renal cortex was studied on 61 old male white outbred rats: ischemic and contralateral - after 20-minute ischemia followed by renal reperfusion of one kidney (1, 3, and 48 h); the control group included intact rats. Direct spectrophotometry of an aqueous solution of a thermocoagulant of renal cell lysates was used as a test method. Results. 20-minute ischemia of one of the kidneys was accompanied by purine recession in both kidneys, to a greater extent in the ischemic one. In the early stages of reperfusion (1-3 h), the similar purine shifts and their estimated coefficients were recorded in the kidneys. The UA level was equally low, as it was during ischemia; after 1 hour of reperfusion, concentrations of other purines in the contralateral kidney were restored to intact values, and in the ischemic kidney, they did not reach the intact level even in 3 hours. As the intensity of purine metabolism increased, the activity of xanthine oxidase and the severity of hypoxia decreased. In 48 hours, the content of all purines decreased again, UA level being lower than ischemic values; the dynamics of the intensity of purine metabolism, xanthine oxidase activity and manifestations of hypoxia corresponded to the early stages of reperfusion, but its severity was greater. Conclusion. The data obtained should be taken into account in the management of aged male patients who underwent ischemia-reperfusion of one kidney in the early postoperative period.