Abstract: Objective To investigate the effect of hyperoxia treatment on the expression of Bmi1 and Lgr5 in intestinal stem cells of neonates with different ages. Methods Neonatal rats were randomly divided into normal air control group and hyperoxia group (85% O2) and sacrificed at different ages (3 days, 7 days, 10 days, 14 days).Intestinal specimens were collected, the expression of Bmi1 and Lgr5 of its intestinal stem cells was detected by immunohistochemistry, Western blott, and real-time PCR. Results The protein and mRNA expression levels of Bmi1 and Lgr5 in the hyperoxia group were significantly lower than those in the normal control group at different ages (P<0.05).Conclusions The expression of Bmi1 and Lgr5 in the intestinal stem cells of newborn rats at different ages was decreased in hyperoxia environment. Therefore, hyperoxia is considered to affect the growth and development of intestinal stem cells in neonatal rats, which may be the reason of hyperoxia-induced intestinal damage.

Key words: Key words：hyperoxia, intestinal stem cells, Bmi1, Lgr5