Effect of maternal intrauterine infection on the expression of tumor necrosis factor-α and cell apoptosis in fetal rat brain

Objective: To study the expression of tumor necrosis factor-α(TNF-α) and cell apoptosis in fetal rat brain after maternal intraperitoneal injection of lipopolysaccharides(LPS).Methods: The pregnant rats on gestation day 18 were randomly divided into control group and LPS experimental group.The rats in LPS group and control group were injected intraperitoneally with LPS of different doses and equal amount of normal saline,respectively.The expression of TNF-α in fetal brain tissue was measured by reverse transcriptase polymerase chain reaction and immunohistochemical method at each time point after the injection of LPS of 0.4,0.8,2,and 4 mg/kg.The cell apoptosis in fetal rat brain was determined by TUNEL method 48 hours after the injection of LPS of 0.4 mg/kg.Results: The expression levels of TNF-α protein and mRNA in rats injected with LPS of different doses were significantly higher than those in controls(P 0.05),and the higher the dose of LPS,the more significant the statistic difference(P 0.01).The expressions of TNF-α protein and mRNA in rats injected with LPS of 0.4 mg/kg were significantly higher than those in controls 1 hour after the injection of LPS(P 0.01),reached the peak 4 hours later,and were still significantly higher than those in controls 8 hours later(P 0.05).A mass of apoptotic cells were found 48 hours after the injection of LPS,and the number of apoptotic cells in rats injected with LPS was significantly higher than that in controls(P 0.01).Conclusion: LPS could stimulate the expression of TNF-α and increase the cell apoptosis in fetal rat brain after maternal intraperitoneal injection of LPS,which indicates TNF-α may be an important cytokine in the fetal rat brain injury inducing by LPS.