Are neuronal markers and neocortical graft-host interface influenced by housing conditions in rats with cortical infarct cavity?

The aim was to study if exposure to an enriched environment influenced graf t-host interface and neuronal markers in neocortical grafts implanted in co rtical infarct cavities 3 weeks after distal ligation of the middle cerebra l artery in adult hypertensive rats. Half the rats were exposed to an enric hed environment for 2 h daily 5 days a week starting 1 week after the arter ial ligation, The brain was fixed by perfusion 4 weeks postgrafting. The im munoreactivity to glial fibrillary acidic protein, microtubule associated p rotein 2, and synaptophysin was studied in coronal paraffin-embedded sectio ns. A distinct glial border separated the infarct cavity from the surroundi ng brain in sham-transplanted rats. Most grafts filled the larger part of t he infarct cavity. In 8 of 18 transplants, 4 in each experimental group, pa rt of the transplants protruded through the thin glial membrane that deline ated the transplant-host interface into the adjacent host brain tissue. Mic rotubule associated protein 2 immunostained sections indicated bridging of dendrites in the host-transplant interface. Synaptophysin immunoreactivity was significantly higher in grafts than in contralateral cortex. However, g raft morphology and neuronal marker immunoreactivity did not differ between rats housed in standard and activity stimulating cages. (C) 1999 Elsevier Science Inc.