缺氧缺血性脑损伤新生大鼠褪黑素受体的变化

Effects of exogenous melatonin on adrenal gland melatonin receptor 1 in hypoxic-ischemic brain damage in neonatal rats

目的观察外源性褪黑素(melatonin,MT)对新生大鼠缺氧缺血性脑损伤(hypoxic-ischemic braindamage,HIBD)干预后不同时间点肾上腺组织中褪黑素受体1(melatonin receptor 1,MR1)mRNA和血浆皮质酮(corticosterone,CS)浓度的变化。方法新生7日龄的SD大鼠随机分为治疗组(T)、模型组(K)、假手术组(H)和生理组(S),在不同时间点采用逆转录多聚酶链式反应法(RT-PCR)半定量测定各组肾上腺组织中MR1 mRNA的表达,放射免疫分析法检测血浆CS的浓度。结果HIBD后2 h肾上腺组织中MR1的表达显著下调,而此时血浆CS水平显著升高,4 h达高峰(P<0.05),与应激程度相符;MT干预后CS浓度以及MR1变化均不明显(P>0.05)。结论外源性MT可能通过自身受体调控应激激素,抑制HIBD后的过度应激损伤。

Objective To study the effect of exogenous melatonin （MT） intervention on the melatonin receptor 1 （MR1） mRNA and cortieosterone （CS） in adrenal gland in hypoxic-ischemic brain damaged （HIBD） neonatal rats. Methods Postnatal 7-day-old Sprague-Dawley rats were randomly divided into four groups （model group, sham operation group, melatonin treated group, physiological control group）. The expression of MR I mRNA was analyzed by senti-quantitative reverse transcriptase polymerase chain reaction （RT-PCR） . Plasma CS level was determined by radioimmunoassay （RIA）. Results In HIBD rats, the level of CS was significantly elevated at 2 hours and peaked at 4 hours after HIBD （P 〈 0.05）, which was coincident with stress rsponse. After the intervention of exogenous MT, the level of CS and the expression of MRI mRNA had no significantly changes （P 〉 0.05）. Conclusions Exogenous MT may restrict the excess stress response by regulating the level of CS and expression of MR1 mRNA after HIBD.