Structural Effects of Chronic Cadmium Exposure on the Kidney and Liver of Adult Wistar Rats: A Dose-Response Histomorphometric Study

Cadmium is a heavy metal present in fertilisers, industrial effluents, and contaminated food crops, and its chronic accumulation in biological tissues produces dose-dependent nephrotoxicity and hepatotoxicity. In Nigeria, cadmium contamination of agricultural soils and groundwater is a documented problem in mining communities of the North Central zone, yet experimental histomorphometric dose-response data linking cadmium exposure levels to kidney and liver structural damage remain limited. This study aims to evaluate the dose-response relationship between chronic oral cadmium chloride administration and histomorphometric changes in the kidney and liver of adult Wistar rats. Rats will receive cadmium chloride at three doses (0.5, 1.0, and 2.0 mg per kilogram body weight daily) by gavage for ten weeks, compared with vehicle-treated controls. Kidney sections will be assessed for proximal tubular cell height, glomerular diameter, and interstitial inflammation. Liver sections will be evaluated for hepatocyte nuclear area, hepatic cord architecture, and portal fibrosis. Metallothionein immunostaining will be performed as a marker of cadmium-induced cellular stress response. The study anticipates establishing dose-dependent structural damage profiles for kidney and liver that will inform safe exposure thresholds relevant to Nigerian agricultural and industrial worker populations.

Keywords: cadmium, nephrotoxicity, hepatotoxicity, histomorphometry, dose-response