Structural changes in lungs of magnesium-deficient weanling rats dying spontaneously or after spontaneous recovery from the seizure-shock episode. Possible methods for sudden infant death syndromes

Abstract

A light and electron microscopic study of Mg-deficient weanling rats showed structural changes of the lungs associated with the audiogenic seizure-shock episode, and with sudden, spontaneous death or spontaneous recovery after the shock episode. Pathogen-free weanling males were fed a Mg-deficient (Mg-0) or Mg-sufficient (Mg-100) diet and were raised in a gnotobiotic environment. Mg-100 rats (n = 16), unstressed or stressed with noise or strychnine, showed normal lungs. Mg-0 rats (n = 20) experienced audiogenic seizure-shock, followed by hyperventilation with tonic-clonic hyperextension of the back and extremities. The lungs of Mg-0 rats sacrificed during shock showed marked hemorrhage, including petechiae; edema; and atelectasis. Eight that died after a post-shock period of hyperventilation and hyperextension of the spine showed partial recovery of the pulmonary lesion; they showed well-expanded lungs, pleural petechiae, persistent congestion, with mild to moderate pathology. Mg-0 rats killed for study 2 days after the seizure-shock episode showed few small areas of residual lung pathology. Ultrastructural changes after Mg-O shock included aggregated platelets, leukocytes, and occasional reticulocytes in congested capillaries. Surfactant was disrupted during Mg-0 seizure-shock, but a layer closely applied to the surface of the epithelium was evident 2 days after shock. Mg-0 rats dying spontaneously showed nonspecific structural changes of the lung similar to changes reported in the sudden infant death syndrome (SIDS).