Cellular proliferation and infiltration following interstitial irradiation of normal XXXX brain is altered by an inhibitor of polyamine synthesis.

@entity1603 @entity11691 @entity235 @entity1161 @entity4869 @entity11747
PURPOSE: The objectives of this study were to quantitatively define proliferative and infiltrative cell responses after focal 125I irradiation of normal brain, and to determine the effects of an intravenous infusion of @entity11747 ( @entity11747 ) on those responses. METHODS AND MATERIALS: Adult @entity235 were irradiated using high activity 125I sources. Saline (control) or @entity11747 (150 mg/kg/day) was infused for 18 days starting 2 days before irradiation. At varying times up to 8 weeks after irradiation, brain tissues were collected and the cell responses in and around the focal lesion were quantified. Immunohistochemical stains were used to label astrocytes ( @entity4869 ), vascular endothelial cells ( @entity11691 ), polymorphonuclear leukocytes (PMNs; MAC 387) and cells synthesizing deoxyribonucleic acid (DNA) ( @entity1603 ). Cellular responses were quantified using a histomorphometric analysis. RESULTS: After radiation alone, cellular events included a substantial acute inflammatory response followed by increased @entity1603 labeling and progressive increases in numbers of capillaries and astrocytes. @entity11747 treatment significantly affected the measured cell responses. As in controls, an early inflammatory response was measured, but after 2 weeks there were more PMNs/unit area than in controls. The onset of measurable @entity1603 labeling was delayed in @entity11747 -treated animals, and the magnitude of labeling was significantly reduced. Increases in astrocyte and vessel numbers/mm2 were observed after a 2-week delay. At the site of implant, astrocytes from @entity11747 -treated @entity235 were significantly smaller than those from controls. CONCLUSIONS: There is substantial cell proliferation and infiltration in response to interstitial irradiation of normal brain, and these responses are significantly altered by @entity11747 treatment. Although the precise mechanisms by which @entity11747 exerts its effects in this model are not known, the results from this study suggest that modification of @entity1161 may be possible by manipulating the response of normal cells to injury.
