Text Box: INFLUENCE ON APOPTOSIS AND BCL-2 LEVEL OF MODEST HYPOTHERMIA TO NOENATAL RATS WITH CEREBRAL ISCHEMIA Li R-L, Guo Y-L Department of Pediatrics, Second Hospital of Xi’an Jiao Tong University, Xi’an, China Objective: To investigate the influence on apotosis and Bcl-2 level of hypothermia to neonatal rats with hypoxic-ischemic brain damage (HIBD), and their relationship. Methods: Established the HIBD model of neonatal rats and observed the apoptosis cells and Bcl-2 level by TUNEL technique or immunochemist technique. Results: HIBD neonatal rats had apoptosis peak when they were 8 days old (p<0.01), hypothermia reduced apoptosis cells (p<0.01), and postponed the apoptosis top; Bcl-2 level increased obviously in HIBD brain when 8 days old (p<0.01), hypothermia reduced the level (p<0.01); it was positive rank correlation between Bcl-2 level and apoptosis cells in hippocampi or cortex tissue when the rats were 8 days old, and the correlation coefficient was 0.88 or 0.71 (p<0.05); it was also positive rank correlation between Bcl-2 level and apoptosis cells in hippocampi when the rats were 10 days old, the correlation coefficient was 0.75 (p<0.05), but it was negative rank correlation between Bcl-2 level and apoptosis cells in cortex when 10 days old. Conclusion: Apoptosis increased in the early time after HIBD in neonatal rats, the level of Bcl-2 was identical with the value of apoptosis cells; hypothermia reduced apoptosis and Bcl-2 level, postponed apoptosis top, so protected the HIBD brain; hypothermia could not completely inhibit Bcl-2 process. 1128