Ultrastucture of the central nervous system after prolonged hypoxia

Summary Chronic hypoxia was induced in rats by subjecting them to a low oxygen atmosphere (10% O₂ and 90% N₂) up to 24 days. Electron microscopy revealed striking alterations in nerve cells of the central nervous system. During the first 4 days, moderate swelling was noted in the Golgi complex in the mitochondria of some neurons. From the 6th to 24th days, alterations of these organelles became more pronounced: Many neurons and their processes exhibited varying degrees of cytoplasmic swelling, and inclusion bodies resembling myelin-figures were found in the perikaryon. Bizarre forms of tubular profiles occurred within the axoplasm of many nerve fibers. The presynaptic terminals became greatly enlarged, containing either unusual multilamellar bodies or clumped vesicles. These results indicated that prolonged hypoxia causes profound changes in the central nervous tissue that do not occur in the acute state.This study was supported by the Dorothy R. Victor Memorial Fund, the Lusyd Wright Hitchcock Memorial Research Fund and the Buswell Foundation.