Effect of Cysteine on Transforming Growth Factor β1 as the Main Cause of Renal Disorder in a Rat Model of Diabetic Nephropathy

​Background and purpose: Glycation products, oxidative stress, and inflammation contribute to the development of diabetic nephropathy (DN) due to the elevation of transforming growth factor-β1 (TGF-β1). This study aimed at investigating the effect of Cysteine (Cys) on TGF-β in DN rat model. Materials and methods: In this experimental study, 40 male Wistar rats were randomly divided into four groups (n=10 per group): control, Cys, DN, and DN + Cys. DN was induced in rats by nephrectomy of the left kidney and injection of streptozotocin. The Cys and DN groups were treated with Cys (0.05% in dirking water) for three months. Glucose, insulin, diverse glycation products, lipid profile, oxidative stress markers, TNF-α, proteinuria, and serum creatinine levels were determined in all rats. Data analysis was done in SPSS V16. Results: Cys decreased the sera level of TGF-β1, renal dysfunction parameters, diverse Glycation, oxidative stress, and inflammatory markers in DN rats. Furthermore, the treatment improved glycemia and dyslipidemia (P> 0.001). Conclusion: Cysteine with antioxidant, anti-glycating, and anti-inflammatory properties ameliorated DN owing to advantageous effects on glucose and lipid metabolism in rats with diabetic nephropathy. Furthermore, this treatment showed multiple protective effects on kidney by reducing the TGF- β1 levels.