Possible protective role of silybin against polymyxin E-induced toxic effect in rat kidneys: A biochemical approach

Polymyxin E was used for treating gram-negative bacterial infections but not recently for fear of its nephrotoxicity. Silybin has potential to counteract nephrotoxicity; however, few studies have investigated its protective effect on the kidney in an animal model. The purpose of the present study was to assess whether silybin could decrease elevated urine and serum renal biochemical markers induced by polymyxin E in rat kidney.

Forty rats were divided randomly into four groups of 10 rats: control (I), vehicle (II), treatment (III, using polymyxin E), and protection (IV, using silybin and polymyxin E). Urine was collected daily for 7 days to test for N-acetyl-beta-D-glucosaminidase (NAG). Serum was collected after euthanizing the rats on day 7 to test kidney functions. RESULTS Group III had significant increases in NAG (all P < 0.001) compared with the other groups, but no differences were found between the other groups. Significant differences in kidney functions were found between Group III and Groups I and II, and between Group IV and Groups I and II (all P < 0.001). No differences were found between Groups III and IV.

Group III results suggested an affection of the renal glomeruli and tubules, and Group IV results suggested a possible protective effect of silybin against polymyxin E-induced nephrotoxicity. Additional studies are recommended that use different doses of silybin for Groups III and IV to test for statistical differences for kidney functions and that test the protective effect of silybin against nephrotoxicity induced by polymyxin E in humans.