sb-415286 and Necrosis

To quantify the effectiveness of SB415286, a specific inhibitor of GSK-3β, as a neuroprotectant against radiation-induced central nervous system (brain) necrosis in a mouse model.. Cohorts of mice were treated with SB415286 or dimethyl sulfoxide (DMSO) prior to irradiation with a single 45-Gy fraction targeted to the left hemisphere (brain) using a gamma knife machine. The onset and progression of radiation necrosis (RN) were monitored longitudinally by noninvasive in vivo small-animal magnetic resonance imaging (MRI) beginning 13 weeks postirradiation. MRI-derived necrotic volumes for SB415286- and DMSO-treated mice were compared. MRI results were supported by correlative histology.. Mice treated with SB415286 showed significant protection from radiation-induced necrosis, as determined by in vivo MRI with histologic validation. MRI-derived necrotic volumes were significantly smaller at all postirradiation time points in SB415286-treated animals. Although the irradiated hemispheres of the DMSO-treated mice demonstrated many of the classic histologic features of RN, including fibrinoid vascular necrosis, vascular telangiectasia, hemorrhage, and tissue loss, the irradiated hemispheres of the SB415286-treated mice consistently showed only minimal tissue damage. These studies confirmed that treatment with a GSK-3β inhibitor dramatically reduced delayed time-to-onset necrosis in irradiated brain.. The unilateral cerebral hemispheric stereotactic radiation surgery mouse model in concert with longitudinal MRI monitoring provided a powerful platform for studying the onset and progression of RN and for developing and testing new neuroprotectants. Effectiveness of SB415286 as a neuroprotectant against necrosis motivates potential clinical trials of it or other GSK-3β inhibitors.

Topics: Aminophenols; Analysis of Variance; Animals; Brain; Colony-Forming Units Assay; Dimethyl Sulfoxide; Female; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Magnetic Resonance Imaging; Maleimides; Mice; Mice, Inbred BALB C; Necrosis; Neuroprotective Agents; Radiation Dosage; Radiation Injuries, Experimental; Radiation-Protective Agents; Radiosurgery; Survival Analysis