Structural characteristics of the kidney in conditions of experimental hypothermia.

OBJECTIVE: Aim: To investigate histological, ultrastructural, and morphometric changes in the wall of arterial vessels, glomerular and peritubular capillaries, and convoluted tubules of the kidney under the influence of a cold factor in an experiment. PATIENTS AND METHODS: Materials and Methods: The experiment was conducted on 80 mature white Wistar male rats, 10 of which served as controls. Animals were divided into 7 groups of 10 animals each according to experimental time points: at the peak of cooling and at 1, 3, 7, 14, 21, and 30 days of the recovery period. All procedures with animals were performed according to bioethical standards. Experimental-morphological analysis was conducted using histological, electron microscopic, and morphometric research methods. RESULTS: Results: It was established that hypothermia causes vasoconstriction of the kidney's arterial vessels. From day 1 of the post-hypothermic period, edematous changes develop, which increase maximally by day 3 and persist through day 7 of the experiment. Starting from day 14, edematous changes decrease and structural organization of kidney parenchyma is restored. Reparative processes are completed by day 30. CONCLUSION: Conclusion: Profound renal hypothermia causes a complex process: early vascular spasm leading to ischemia, subsequent inflammatory enhancement of damage with maximum effect at days 3-7, followed predominantly by reversible recovery with isolated foci of irreversible remodeling.