未成熟大鼠出生后感染对脑白质中SOX10蛋白表达的影响

Expression of SOX10 in cerebral white matter in immature rats with postnatal infections

目的研究未成熟大鼠出生后感染对脑白质中SOX10蛋白表达的影响。方法将96只新生SD大鼠随机分为缺氧组、脂多糖组和对照组;脂多糖组及缺氧组新生大鼠于生后第3、6天予以腹腔注射脂多糖0.25 mg/kg,对照组注射等量的生理盐水;缺氧组在注射脂多糖同时,自生后第3天起置于常压缺氧舱中,连续37℃恒温水浴,以2 L/min的速度向缺氧舱中输入含有8%O2和92%N2的混合气体,通气2 h;分别于生后第7、10、14、21天,每次每组处死8只大鼠,取脑白质,HE染色后光镜下观察脑白质区病理变化;通过免疫组织化学方法及Western-Blot检测脑白质区SOX10蛋白的表达变化,用Western-Blot检测Toll样受体-4(TLR-4)的表达变化。结果脂多糖组、缺氧组的SOX10阳性细胞数、SOX10和TLR-4蛋白表达均在第7天开始增加,第10天时达高峰,之后逐渐下降,各时间点间两两比较差异均有统计学意义(P<0.05);对照组在各时间点均只见少量阳性细胞以及SOX10和TLR-4的少量表达,差异无统计学意义(P>0.05)。在不同时间点,脂多糖组、缺氧组和对照组三组之间SOX10阳性细胞数、SOX10和TLR-4蛋白表达的差异均有统计学意义(P均=0.000);均为缺氧组最高,其次为脂多糖组;各时间点两两比较,差异均有统计学意义(P<0.05)。结论未成熟大鼠出生后感染可引起脑损伤,缺氧与感染双重因素同时存在可加重脑损伤程度,而高表达SOX10蛋白可能有保护作用。

Objective To explore the effect of postnatal infection on SOX10 expression in cerebral white matter in immature rats. Methods A total of 96 newborn SD rats were randomly divided into hypoxia group, lipopolysaccharide（LPS） group, and control group. At day 3 and 6 after birth, the rats in LPS group and hypoxia group were intraperitoneally injected with 0.25 mg/kg of LPS while the rats in control group were injected with normal saline. Meanwhile the rats in hypoxia group were maintained in a hypoxic tank under atmospheric pressure and thermostatic water bath at 37℃ for 2 hours of ventilation with mixed gas containing 8% O2 and 92% N2 at a rate of 2 L/min starting 3 days after birth. At day 7, 10, 14, 21 after birth, eight rats in each groups were sacrificed and the cerebral white matter was extracted. HE staining was performed to observe the pathological changes of cerebral white matter by light microscopy. The expression of SOX10 in cerebral white matter was determined by immunohistochemical and Western blotting analysis. The expression of TLR-4 was determined by Western blotting. Results In LPS group and hypoxia group, the SOX10 positive cells and expressions of SOX 10 and TLR-4 were increased at day 7, reached the peak at day 10, and then gradually declined. There were significant differences between any two time points（P〈0.05）. In control group, there were a few positive cells and limited expressions of SOX 10 and TLR-4 and there were no differences between any two time points（P〈0.05）. At each time point, the difference in the SOX10 positive cells and the expressions of SOX 10 and TLR-4 were statistically significant among three groups（P〈0.05） in the order of hypoxia group LPS group control group and there were significantly differences between each groups（P〈0.05）. Conclusions Postnatal infections can lead to cerebral white matter lesions in immature rats. The existence of both hypoxia and infection can aggravate the brain injury. The high expression of SOX 10 may have the protective effect.