Correlation Between Biochemical And Histological Markers In Experimental Nephrotoxicity: Insights From Anacardium Occidentale Leaf Extract Intervention

Background: Concordance between biomedical and histological markers is critical for robust interpretation of preclinical nephroprotection studies. Objective: To analyse the relationship between commonly used serum renal biomarkers and histopathological damage in albino rat model of carbon tetrachloride (CCl4)-induced nephrotoxicity, exploring the effects of different Anacardium occidentale (cashew) leaf extracts. Methods: thirty adult albino rats were randomized to six groups (n = 5): control, CCl4 -only, CCl4 with N-acetylcysteine (NAC; 100 mg/kg) and CCl4 with aqueous, ethanol, or n-hexane cashew leaf extracts (200 mg/kg each). Serum Urea and creatinine were measured using enzymatic methods alongside detailed histological scoring (0 – 12 scale). Pearson correlation analysis were performed across groups. Results: CCl4 administration significantly elevated serum urea (45.8 ± 4.3 vs. 18.4 ± 1.4 mg/dl; p ˂ 0.001) and creatinine (2.18 ± 0.32 vs. 0.54 ± 0.09 mg/dl; p ˂ 0.001) compared to controls. Both markers exhibited strong positive correlations with composite histological damage scores (urea: r = 0.94, R2 = 0.88; creatinine: r = 0.96, R2 = 0.92; p ˂ 0.001). the ethanol extract group achieved near-normalization of serum markers (urea: 24.1 ± 2.2 mg/dl; creatinine: 0.72 ± 0.11 mg/dl) and histological scores (2.4 ± 0.2), comparable to NAC treatment. The n-hexane showed minimal protection with persistently elevated markers. Conclusion: Biochemical and histological endpoints are tightly correlated in CCl4 -induced nephrotoxicity. The ethanol extract of A. occidentale leaves demonstrates robust nephroprotection, supporting its therapeutic potential for renal health. Keywords: Nephrotoxicity; Anacardium occidentale; Carbon tetrachloride; Renal biomarkers; Histopathology, Phytomedicine.