Growth-associated protein-43 is increased in cerebrum of immature rats following induction of hydrocephalus

Abstract

Hydrocephalus is associated with gradual progressive impairment and destruction of cerebral axons and neurons. Growth associated protein-43 appears to be permissive for neuro-axonal regeneration and synaptic remodeling. Hydrocephalus was induced in three-week-old rats by injection of kaolin into the cisterna magna. Compared to controls, cerebral growth- associated protein-43 messenger RNA was significantly up-regulated one week after kaolin injection and the overall cerebral growth-associated protein-43 protein level was significantly higher at four weeks when the ventricles were severely enlarged. One and three weeks after kaolin injection, growth- associated protein-43-like immunoreactivity was increased in periventricular axons, and also in the cerebral cortex at three weeks. Hydrocephalic rats that had been treated by shunting after one week, exhibited growth- associated protein-43 messenger RNA and protein levels intermediate between hydrocephalic rats and control rats. The increase in periventricular axon growth-associated protein-43, early in the course of experimental hydrocephalus, suggests that through early intervention there may be a chance for preventing or reversing the axonal injury. Cortical expression of growth associated protein-43 suggests that an alteration in synaptogenesis may also occur.