Expression of transforming growth factor-beta 1 in periventricular leukomalacia

The expression of transforming growth factor-beta 1, which has neurotrophic effects, was investigated in 25 neonates with periventricular leukomalacia using immunohistochemistry. In controls, transforming growth factor-beta 1 immunoreactivity was not detected in the cerebral white matter or cortex. Of the 25 cases of periventricular leukomalacia, transforming; growth facto r-beta 1 immunoreactivity was found in 16, and was distributed mainly in th e cytoplasm of astrocytes, being prominent around necrotic foci in the whit e matter. The immunoreactivity was negative or weak at the acute stage of p eriventricular leukomalacia, and increased at the subacute stage and then d ecreased or was absent at the chronic stage. Astrocytes that were moderatel y or markedly positive for transforming growth factor-beta 1 were not found before 27 weeks' gestation, but were observed after 32 weeks' gestation in the white matter of the brains of neonates with periventricular leukomalac ia. Transforming growth factor-beta 1 expression tended to be more obvious in focal periventricular leukomalacia than in widespread or diffuse periven tricular leukomalacia. Our results suggest that transforming growth factor- beta 1 could be involved in the delayed glial response rather than the init ial glial activation, and could play a role in the inhibition and repair of injury in periventricular leukomalacia. Exogenous transforming growth fact or-beta 1 could have therapeutic potential for periventricular leukomalacia .