Ultrastructural changes in the glomerular filtration barrier of the kidneys in rats following acute paraoxon poisoning

BACKGROUND: Paraoxon is an organophosphate compound, chronic poisoning by which has various manifestations. Individuals exposed to organophosphates often develop glomerular and/or tubular sclerosis. Ultrastructural changes in the glomerular filtration barrier (GFB) of the kidneys in experimentally induced acute paraoxon poisoning have not been described in available scientific publications, underscoring the relevance of this study. AIM: This study aimed to identify ultrastructural changes in the glomerular filtration barrier of the kidneys in rats following acute paraoxon poisoning in sublethal doses. METHODS: Kidney fragments were obtained from male outbred albino rats (Rattus norvegicus) 1, 3, and 7 days after paraoxon poisoning. Three modes of paraoxon exposure were used. Immunohistochemical, electron microscopy, and morphometric analyses were performed on the kidney tissue, followed by statistical analysis of the results. RESULTS: Ultrastructural changes in the GFB were observed in all modes of paraoxon exposure. Endothelial cells of glomerular capillaries showed an increased diameter of fenestrations, accompanied by a decrease in their density. Podocytes exhibited changes in the size of the foot processes and a reduction in the number of third-order extensions that normally adhere to the glomerular basement membrane. All three experimental groups showed an increase in the thickness of the glomerular basement membrane on day 7 after poisoning. The most pronounced morphological changes in GBF structures following paraoxon exposure were observed in the endothelial cells of the glomerular capillaries. CONCLUSION: Acute paraoxon poisoning leads to ultrastructural changes in the GFB in rat kidneys. The data obtained contribute to understanding the mechanisms of glomerulosclerosis development following chronic exposure to this toxin.