Hyperbaric oxygen therapy prevents epithelial atrophy in distal tubules and TGF-β1 overexpression in diabetic rat kidneys

Diabetic nephropathy (DN) is one of the most relevant and prevalent microvascular complications associated with Diabetes Mellitus. In recent years, hyperbaric oxygen therapy (HBO) has been used to mitigate tissue damage caused by hypoxia, thereby attenuating inflammatory processes. This study aimed to explore morphological aspects associated with DN in rats subjected to HBO. Forty-eight Wistar rats were divided into the following groups: C (normoglycemic animals), n = 12; C + HBO (normoglycemic animals submitted to HBO), n = 12; D (diabetic animals) n = 12; D + HBO (diabetic animals submitted to HBO), n = 12. The C + HBO and D + HBO groups were daily treated with HBO at 2.5 atmospheres absolute pressure (ATA) for 60 min, 5 days a week, for 5 weeks. Kidneys were collected for assessment of structural changes in the tissue parenchyma, assessment of renal fibrosis and renal protein expression of tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1). Our results showed that group D had hyperglycemia and weight loss, and that there was also an increase in the renal corpuscle, Bowman’s space, and distal tubular epithelium, as well as accumulation of collagen. HBO administration effectively prevented glomerular hypertrophy and attenuated the expression of TNF-α and TGF-β1. It also positively affected renal tubules, inhibiting the development of tubular atrophy. These findings suggest that HBO was effective in attenuating the initial alterations observed in DN. Graphical Abstract