Lead cardiomyopathy in mice: a correlative ultrastructural and blood level study.

This is a correlative study of ultrastructural changes in the myocardium and the blood lead levels (BLLs) in acute lead toxicity in mice. No substantial ultrastructural changes were observed with BLLs of less than 20 mug/100ml. Blood lead levels of 20 mug/100ml and above were associated with nuclear chromatin clumping and nucleolar disorganization. Sarcotubular dilation and mitochondrial changes characterized by mitochondrial enlargement, cristal disorientation, and an increase in intramitochondrial matrix were observed with BLLs of 40 mug/100ml and over. Blood lead levels of 60 mug/100 ml and above were associated with local myofibrillar degeneration, focal intercalated disk disjunction, and interstitial cell changes characterized by prominent endoplasmic reticulum and the appearance of cytoplasmic lysosome-like dense bodies. Our findings indicate a differential sensitivity of various myocardial cell organelles to lead and suggest that the changes observed are directly related to the BLLs.