Evaluation of Protective and Therapeutic Potentials of Aqueous Extract of Corn Silk on Gentamicin-Induced Nephrotoxicity in Albino Rats

Abstract

Aim: To evaluate the protective and therapeutic potentials of corn silk extract on gentamicin (CN)-induced nephrotoxicity in albino rats. Study Design: The rats were randomly selected and grouped as follows: Group 1 (NC): Were given only food and water. They served as negative control. Group 2 (PC): Were treated with 80 mg/kg/day of CN over a period of 7 days. They served as the positive control. Protective Treatment: Group 3a (CN+CSP 200 mg/kg): Concurrently treated with 200 mg/kg corn silk extract and 80 mg/kg/day of CN for 7 days. 200 mg/kg corn silk extract continued for 30 days. Group 3b (CN+CSP 400 mg/kg): Concurrently treated with 400 mg/kg corn silk extract and 80 mg/kg of CN for seven days. 400 mg/kg corn silk extract continued for 30 days.  Therapeutic treatment: Group 4a (CN+CST 200 mg/kg): Induction of nephrotoxicity with 80 mg/kg/day of CN for seven days before the administration of 200 mg/kg of corn silk extract for 30 days. Group 4b (CN+CST 400 mg/kg): Induction of nephrotoxicity with 80 mg/kg/day of CN for 7 days before the administration of 400 mg/kg of corn silk extract for 30 days. Methodology: At the end of the treatment, the animals were allowed to fast for 18 hours and later anaesthetized using chloroform. Whole blood samples were collected via cardiac puncture and put into lithium heparin bottles. The samples were then spun at 3500 rpm for 5 minutes to obtain plasma. Kidney specimens harvested were fixed in 10% formol saline. Sections were prepared using histological techniques and stained using Haematoxylin and Eosin stain. Urea was analysed using Berthelot’s enzymatic colorimetric method, creatinine using Jaffe’s enzyme-kinetic method while the estimation of Na+, K+, and Cl- were performed using Ion Selective Electrode (ISE) analyzer. Results: Significantly lower (p<0.05) values of creatinine and urea were seen in protective and therapeutic treatment groups when compared against positive control. Potassium indicated significantly lower values especially in the therapeutic groups when compared against negative control while chloride indicated significantly higher values in 400 mg/kg rats compared with positive control at p<0.05. Histology of the protective treatment groups showed slightly distorted glomerular space, vacuolations, and dilated proximal and distal tubules. The positive control and the therapeutic treatment groups indicated severely damaged glomerulus, glomerular space, proximal and distal tubules as well as loss of parenchymal materials and presence of kupffer cell infiltration were seen but less severe in the therapeutic group compared to the positive control. Conclusion: The results obtained suggest protective and therapeutic potentials of corn silk extract on gentamicin-induced nephrotoxicity in albino rats. However, the therapeutic efficacy was progressively gradual and not be fast-effective as documented in most traditional or herbal literatures.