Long-term alloxan diabetes in the rat. Study of mesangial cell morphology by serial biopsies.

Experimental diabetes in the rat was induced by alloxan (40 mg/kg body weight) and resulted in permanent hyperglycaemia (mean glycaemia: 403.0 mg/100 ml). The animals were left untreated for more than 16 months. The mesangial cell of the renal glomerulus was studied by serial biopsies performed each month under light anaesthesia in the diabetic animals and in normal controls of the same age. Large dense bodies appeared in the cytoplasm after 3 months in the diabetics and after 10 months in the controls. With time, a larger number of mesangial cells contained these dense bodies. At the end stage they seem to be mainly lipidic. When NO3Ag is given in the drinking water the dense bodies accumulate particles of silver, suggesting that they contain fragments of the basement membrane. While the acid phosphatase reaction was negative in biopsy specimens from diabetic animals, it remains possible that the large dense bodies belong to the lysosomial system. This point, as well as the pathologic significance of the dense bodies is currently investigated.