Potential therapeutic impacts of vitamin D on hypothyroid-induced heart and kidney fibrosis and oxidative status in male rat

There are several interactions between thyroid hormones (THs) and kidney and heart function. Consequently, THs deficit results in profound changes in renal and cardiac function regulation. Interestingly, emerging evidence suggests that vitamin D (Vit D) may benefit to fibrotic lesions in various tissues. Herein, this study was designed to investigate the potential impact of Vit D on renal and cardiac fibrosis in hypothyroid rats. Forty male Wistar rats were divided into four groups as follow: control, hypothyroid (0.05% PTU in drinking water), and hypothyroid + Vit D (PTU and doses of 100 or 500 IU/kg/day, by gavage) groups. After 6 weeks, biochemical parameters such as creatinine and urea in serum samples, and oxidative stress markers including malondialdehyde (MDA), total thiol groups, and superoxide dismutase (SOD) in renal and cardiac tissues homogenate were measured. Also, renal and cardiac fibrosis was evaluated histologically using Masson's trichrome staining. Hypothyroidism significantly increased creatinine and urea. Also, in hypothyroid group renal and cardiac fibrosis as well as MDA were increased, while anti-oxidative markers including total thiol group and SOD were decreased. Administration of Vit D significantly improved these alterations in oxidative stress markers and fibrosis in renal and cardiac tissues. In conclusion, this study highlighted that Vit D supplementation reduced renal and cardiac fibrosis and improved oxidative stress. These results support the emerging experimental findings linking Vit D being introduced as a potential therapeutic agent.