Expression of myelin basic protein, glial fibrillary acidic protein, interleukin-1β and tumor necrosis factor-α in neonatal rats brain after intrauterine exposure on lipopolysaccharide

Abstract

Objective To probe into the expression of inflammatory factrors and white matter damage after intrauterine lipopolysaccharide(LPS) exposure in neonatal rats brain. Methods LPS (0. 4 μg) was administrated into the intrauterine cavity between every two embryo sacs of SD rats at day 19 of gestation in LPS group(n= 14) , while pyrogen-free saline was administrated in control group (n=10). Neonatal brain tissues were collected at postnatal day 1,3,7 and 11. Reverse transcription-polymerase chain reaction analysis was used to examine mRNA expression of interleukin-1βand tumor necrosis factor-a, and immunohistochemistry was used to evaluate the expression of myelin basic protein and glial fibrillary acidic protein in neonatal brain tissues. Statistical analysis was performed using t test. Results Placental hematoxylin-eosin staining in the LPS group showed distinct inflammatory cell infiltration, prominent hyperplasia of interstitial tissue and narrowed capillary. Myelin basic protein in cerebellum and cerebrum of neonatal rats at postnatal 11 days in LPS group was much weaker than in control group (cerebellum: 1. 29 ±0. 76 vs 2. 43 ±0.79, t =2. 038,P=0.045; cerebrum: 1. 71 ±0. 49 vs 2.50±0.76, t= 2. 420,P = 0.032). Glial fibrillary acidic protein of neonatal rats brain at postnatal 11 days in LPS group was much stronger than in control group (hippocampus: 2.71±0.49 vs 1.75±0.50, (t=-3.029, P = 0.026. corpus callus: 2.40±0.55 vs 1. 50±0. 58, t= -2. 646,P = 0. 019. cerebrum: 1. 50±0. 55 vs 1. 00±0. 00, t= -2. 236, P=0. 049. cerebellum: 2. 80 ±0. 45 vs 1.60 ±0.55, t = -3.08,P =0.009). But there was no statistical difference between LPS group and control group in the expressions of IL-1β and TNF-α mRNA in neonatal rats brain at each time point. Conclusions Intrauterine LPS exposure may decrease the placental blood flow resulting in neonatal low birth weight and white matter damage, which characterized by astrogliosis and hypomyelination. Key words: Pregnancy complications, infectious) Lipopolysaccharides; Animals, newborn