Text Box: EFECTS OF INSULIN-LIKE GROWTH FACTOR-1 ON THE FREE CALCIUM CONCENTRATION OF HYPOXIC-ISCHEMIC BRAIN DAMAGE IN NEONATAL RATS Liu DL, Chen C, Wang Q, Yang Y Children’s Hospital, Fudan University, Shanghai, China Objective: To study the effects of insulin-like growth factor-1 (IGF-1) on the free calcium concentration in brain cells of hypoxic-ishcemic brain damage in neonatal rats (HIBD). Methods: The 7-day SD rats were randomly divided into three groups: the model (n=6), treatment (n=6) and sham (n=6). In the former two groups, the right carotid arteries of the rats were separated, ligated, and 3-4 hours later, the rats were subjected to 8% O2.In the treatment group, each rat was injected intraventricularly in the right hemisphere with 10µg of IGF-1. In the sham group, the right carotid arteries of the rats were only separated. All the rats were decapitated 10 hours after hypoxia, then the cells of right cerebral cortexes were isolated and incubated for 40 minutes with 5µmol/L Fura-2/AM. The loaded cells were observed under fluorescence microscope and the free calcium concentrations were determined as the ratio of F340/F380 via KS400 image analysis system. Results: The mean ratios of F340/F380 of the sham, model and treatment groups were 1.363±0.135, 1.786±0.127 and 1.172±0.122, respectively. The differences between the three groups were significant verified by one-way analysis of variances (p< 0.05). Conclusion: The free calcium concentrations in the brain cells rise dramatically 12 hours after hypoxia-ischemia, and IGF-1 can reduce the calcium overload significantly. Due to the role of intracelluar calcium overload in the brain cell damage, our results suggest that IGF-1 may be a protective factor for HIBD. 2337