孕酮对缺氧缺血性脑损伤新生大鼠脑组织损伤因子和抗损伤因子表达的影响

Effect of progesterone on expression of brain tissue damage factors and anti damage factors in neonatal rats with hypoxic-ischemic brain damage

目的观察孕酮对缺氧缺血性脑损伤（HIBD）新生大鼠皮层和海马组织中损伤因子TNF-α、IL-1β和抗损伤因子神经生长因子（NGF）、脑源性神经营养因子（BDNF）表达的影响，探讨孕酮神经保护作用的分子机制。方法将48只7日龄新生Wistar大鼠随机分成3组：假手术组、缺氧缺血组、药物预防组。缺氧缺血组和药物预防组新生大鼠先行左侧颈总动脉结扎术，然后置于37℃恒温的密闭容器中，以1．5L／min的速度吸人80mL／L氧气和920mL／L氮气混合气体2．5h建立HIBD动物模型。假手术组仅分离左侧颈总动脉，不结扎，亦不做缺氧处理。药物预防组新生大鼠于建立模型前30min按8mg／kg腹腔注射0．5g／L孕酮溶液，假手术组和缺氧缺血组注射等量的9g／L盐水溶液，24h后处死全部新生大鼠，取左侧脑组织，采用ELISA法检测脑组织TNF-α、IL-1β、NGF和BDNF水平，反转录聚合酶链式反应（RT-PCR）检测TNF-α、IL-1β和BDNFmRNA的表达。结果缺氧缺血组新生大鼠皮层和海马组织中TNF-α、IL-1β、NGF、BDNF水平及其mRNA的表达明显高于假手术组；药物预防组TNF-α、IL-1β水平及其mRNA的表达明显低于缺氧缺血组，而NGF、BDNF水平和mRNA的表达则明显高于缺氧缺血组（P均〈0．05）。结论孕酮可以保护新生大鼠缺氧缺血后引起的皮层和海马损伤，其作用机制与抑制损伤因子的表达和促进抗损伤因子的表达有关。

Objective To study the effect of progesterone on tumor necrosis factor（TNF-α） ,intedeukin-1β （IL-1β）, nerve growth factor（NGF） and brain derived neurotrophic factor（BDNF） expression in the cortex and hippo- campus tissue in newborn rats with hypoxic-ischemic brain damage （ HIBD）, and to discuss the protective molecular mechanism of progesterone on HIBD in neonatal rats. Methods Forty-eight 7-day-old neonatal rats were randomly di- vided into 3 groups ： sham-operated group, hypoxic-ischemic group and pretreatment group. Rats in hypoxic-ischemic group and pretreatment group were subjected to left common carotid artery ligation, then they were exposed to 80 mL/L oxygen and 920 mL/L nitrogen gas in the closed container at 37 ℃ for up to 2.5 h to establish HIBD models. Progeste- rone was injected intraperitoneally into the rats in the pretreatment group 30 min before hypoxia, and solution was injec- ted into the first 2 groups. All the rats were killed at the 24 h after operation. The levels of TNF-α,IL-1β, NGF, BDNF were measured by enzyme linked immunosorbent assay and the expressions of TNF-α,IL-1β, NGF, BDNF mRNA were analyzed by reverse transcription-polymerase chain reaction. Results The contents of TNF-α,IL-1β, NGF, BDNF and their mRNA expressions in hypoxic-ischemic group were significantly higher than those in the sham-operated group. In pretreatment groups, the levels of TNF-α,IL-1β and their mRNA expressions were significantly lower than those in hy- poxic-ischemic group. The levels of NGF, BDNF and their mRNA expressions in pretreatment group were significantly higher than those in hypoxic-ischemic group （ all P 〈 0.05 ）. Conclusions Progesterone exerts neuroprotective effect on hypoxic-isehemie encephalopathy-induced brain damage, and the action mechanism is related to down-regulate the expression of damage factor and up-regulate the expression of anti damage factor.