Probenecid protects against contrast-induced nephropathy through modulation of small Rho GTPases and Pannexin1...

Contrast agents are known to increase the risk of radiocontrast-induced nephropathy (CIN), particularly in elderly, diabetic, or dehydrated patients. However, the exact molecular mechanisms leading to renal injury in CIN remain unclear. Probenecid (PBN), an organic anion transport inhibitor that also inhibits Pannexin1 channels, has been suggested as a potential therapeutic agent in certain nephropathy models. This study aimed to examine the protective effects of PBN in CIN. Additionaly, considering the roles of small RhoGTPases and Pannexin1 in nephropathy and their interactions, we investigated the relationship between these molecules in the same CIN rat model.

CIN was induced in male Wistar rats by a single intraperitoneal (ip.) injection of iohexol. The animals were treated with either saline (i.p) or PBN (150 mg/kg or 300 mg/kg, i.p) twice daily for 5 days following iohexol (3 g iodine/kg) administration. Kidney tissue samples were stained with hematoxylin and eosin to assess tubular injury. Immunohistochemical analysis was also performed to evaluate the expression of RhoA, Rac1, Pannexin1, and active Caspase-3.

Iohexol caused tubular necrosis, dilatation, vacuolization and brush border loss, while high-dose PBN significantly reduced these changes. Rac1, Pannexin1 and active-Caspase 3 expressions were increased in CIN, while RhoA expression was decreased compared to control. High-dose PBN ameliorated these changes, but significant improvement was observed in RhoA expression.

These results indicate that PBN may protect against CIN through modulation of small Rho GTPases (increasing RhoA expressions or altered balance between RhoA and Rac1) and Pannexin1 channels in Wistar rats.