Pulmonary lesion induced by stress in magnesium-deficient rats. A light- and electron-microscopic study

A light- and electron-microscopic study was made of the lungs of magnesium (Mg)-sufficient and Mg-deficient pathogen-free weanling rats raised in a gnotobiotic environment. Mg-sufficient rats were studied unstressed, after mild auditory stress, or after strychnine seizures and showed essentially no pulmonary pathology. Mg-deficient rats were studied with no known seizures or immediately after audiogenic seizure-shock. Light microscopy of lung from Mg-deficient rats with audiogenic seizure-shock revealed atelectasis, generalized edema and hemorrhage, and pleural petechiae. Ultrastructural changes in lung alveoli of Mg-deficient rats with seizure-shock included gaps in capillary endothelium, swelling and separation of endothelial cells from the underlying basement membranes; Type I cell necrosis and separation from basement membranes; and intraalveolar red blood cells, fibrin, and precipitated plasma. The seizure-shock episode of acute Mg deficiency produces structural changes in the lung similar to changes produced by several forms of shock, early acute oxygen toxicity, and the respiratory distress syndrome (RDS) in human neonates.