Intrauterine infection affects early growth and neurobehavioral development in neonatal rats

Abstract

Objective:To explore the effects of intrauterine infection on early growth and neurobehavioral development in neonatal rats. Methods:Escherichia coli (E. coli) was inoculated into uterine cervix of pregnant rats with gestation of 15 d to establish the intrauterine infection model, and the effect on the delivery of pregnant rats was observed. The neonatal rat brain tissue was stained with Hematoxylin-Eosin and the cerebral white matter damage was assessed. Immunohistochemical staining and Western blot analysis were performed to evaluate the expression of glial fibrillary acidic protein (GFAP), 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and neurofilament (NF) in pup brains. Birth weight and early growth development indices were monitored,and neurobehavioral tests were performed to access the change of neurobehavioral development in neonatal rats. Results:The white blood cell count increased significantly in the uterus and placenta of the pregnant rats after intrauterine E. coli infection and no significant impact was observed on the delivery of pregnant rats. Weak staining and focal rarefaction of cerebral white matter from rats at P7 in intrauterine infection group were observed. The expression of GFAP markedly increased (P<0.05) in infection group, while the level of CNPase and NF in pup brains at P7 significantly decreased (P<0.05 or P<0.01). Compared with control group, the neonatal rats in infection group had lower birth weight and slower weight gain during the suckling period (P<0.05 or P<0.01), and the completion times of ear opening, eye opening, surface righting, negative geotaxis, acoustic startle and swimming test in infection group were significantly delayed (P<0.05 or P<0.01). Conclussion:Intrauterine infection in pregnant rats can induce cerebral white matter damage and retardation of early growth and neurobehavioral development in neonatal rats.