Protective effects of Cleome gynandra leaf extract against acute mercury chloride-mediated kidney damage in male wistar albino rats

Abstract

Background: Mercury (Hg) is an environmental pollutant that causes toxic effects in humans or animals exposed to it at toxic levels that impair some organs’ function, with the highest Hg levels observed in the kidney. Associated adverse health effects such as kidney damage, have been reported in populations living in polluted areas including Artisanal Small-scale Gold Mining (ASGM). In Kenya, Masara and Osiri/Mikei artisanal gold miners in Migori County are affected. A promising approach to protecting tissue damage is the use of phytochemicals. Objective: To determine the protective effect of Cleome gynandra (CG) leaf extract on the kidney of male Wistar albino rats exposed to mercuric chloride. Methods: The study was an experimental animal study. Through cold maceration using absolute methanol as a solvent, the CG extract was obtained from dried, homogeneously ground leaves. 30 male albino Wistar rats were grouped into groups of five randomly: Group I - vehicle control; group II - 5 mg mercuric chloride (HgCl2)/kg of body weight (bwt) subcutaneous injection on the 7th day; group III & IV - 250 and 500 mg CG extract /kg bwt daily oral administration, respectively, and 5 mg HgCl2/kg bwt subcutaneous injection on the 7th day; group V - 0.5 mg HgCl2/kg bwt daily subcutaneous injection; and group VI - 0.5 mg HgCl2/kg bwt daily subcutaneous injection with daily 200 mg CG extract/kg for 7 days. Anaesthesis was performed 24 hours after HgCl2 administration followed by the obtaining of blood samples through cardiac puncture for biochemical parameters analysis in groups I - IV and kidney samples for histological examination in groups I - VI after sacrificing. The mean concentrations of the biochemical parameters were compared using the One-Way Analysis of Variance (ANOVA) followed by Tukey post hoc test (p ≤ 0.05). Results: The variations among the groups I - VI were statistically significant for creatinine (p=0.0002), urea (p=0.0002), and albumin (p=0.0082) concentrations. HgCl2 significantly increased urea (p = 0.021) and creatinine (p = 0.032) in the blood compared to the vehicle control. These changes were not prevented by the CG extract. The difference between the groups receiving 250 and 500 mg CG extract/kg bwt was insignificant for creatinine (p=0.972) and urea (p=0.341). These quantitative observations were supported by histological alterations of the kidneys. Albumin in the blood was lower in the treatment groups compared to controls, only significant in treatment group 2 (HgCl2+500mg CG extract/kg bwt) (p=0.005). Administration of 200 mg CG extract/kg bwt limited tissue damage to a minimum at low HgCl2 concentration. Conclusion: At a low mercury concentration, CG was nephroprotective. However, pre-treatment with CG extract was ineffective in nephroprotection against damage induced by the high dose of mercury. Recommendations: The findings of the study to be used in the advancement of the knowledge of CG, the methanolic extract of Cleome gynandra should not be used in the management of high mercury concentrations, and 10% dimethyl sulphoxide can be considered as a solvent for plant extracts in experimental animal study designs for acute conditions. Keywords: Kidney, renal, mercury chloride, Cleome gynandra, urea, albumin, creatinine, histological.