Hepatic morphologic and biochemical changes induced by subacute cocaine administration in mice

The initial event and site of cocaine-induced hepatic injury have not been elucidated. In an attempt to identify the minimal effective dose and the site of injury, we have examined the livers of mice exposed to small daily doses of cocaine, using morphological and biochemical methods. All doses of cocaine greater than 5 mg/kg were able to cause significant elevation of serum glutamic pyruvic transaminase. Light microscopy revealed a progression of centrilobular necrosis as the dose increased from 10-30 mg/kg. The initial morphologic changes observed prior to necrosis included aggregation of intermediate filaments and dilation of rough endoplasmic reticulum with loss of ribosomes. Immunohistochemistry, using antibodies to cytokeratins, showed staining of individual hepatocytes in livers from cocaine-treated animals but not in controls. In contrast to earlier reports, we found little, if any, disruption of mitochondria. In vitro, the direct application of cocaine, norcocaine, and N-hydroxynorcocaine on isolated mitochondria had no effect on the ADP:O or respiratory control ratios, at concentrations up to 2.0 mM. Our studies demonstrate that any early cellular alterations in cocaine-induced hepatic injury are manifested in intermediate filaments and endoplasmic reticulum with no evidence of mitochondrial involvement.