BACKGROUND:Angelica sinensis is a widely used herb in Chinese traditional medicine.It has been shown to improve hypoxia in embryonic rats and reduce nestin expression in neural stem cells,resulting in proliferation of neural stem cells.OBJECTIVE:To study the protective effect of Angelica on neural stem cell proliferation in neonatal rats after intrauterine hypoxia.DESIGN,TIME AND SETTING:The randomized,controlled,experiment was performed at the Department of Histology and Embryology,Luzhou Medical College,China from July 2007 to January 2008.MATERIALS:Because gestational days 14-15 are a key stage in rat nervous system development,21 healthy,pregnant Sprague Dawley rats(14 days after conception)were used for this study.Nestin monoclonal primary antibody was obtained from Chemicon,USA.Angelica parenteral solution(250 g/L)was obtained from Pharmaceutical Preparation Section,Second Affiliated Hospital of Wuhan University,China.METHODS:Rats were randomly divided into a control group(n=5),a hypoxia group(n=8),and an Angelica group(n=8).Saline(8 mL/kg)was injected into the caudal vein of rats in the hypoxia group once a day for seven consecutive days.Intrauterine hypotonic hypoxia was induced using 13% O2 for two hours per day on three consecutive days.Rats in the Angelica group received injections of Angelica parenteral solution(250 g/L);all other protocols were the same as the hypoxia group.The control group procedures were identical to the hypoxia group,but under normal,non-hypoxic conditions.After birth,brain tissues were immediately obtained from neonatal rats and prepared for nestin immunohistochemistry.MAIN OUTCOME MEASURES:Nestin-positive cells in hippocampal CA3 area of neonatal rats in each group were quantified using image analysis to detect signal absorbance.RESULTS:The number of nestin-positive cells increased in the hippocampal CA3 area of neonatal rats in the hypoxia group.The number of nestin-positive cells was less in the Angelica group than in the hypoxia group.Integral absorbance of nestin-positive cells in the hippocampal CA3 area of neonatal rats was significantly higher in the hypoxia group,compared with the control group(P<0.05).The integral absorbance of nestin positive cells was lower in the Angelica group,compared with the hypoxia group(P<0.05).CONCLUSION:Intrauterine hypoxia,induced for 2 hours daily for three consecutive days,with an oxygen concentration of 13%,stimulated the proliferation of neural stem cells.Angelica injection has a protective effect on neural stem cells from neonatal rats following intrauterine hypoxia by decreasing proliferation of neural stem cells.