新生大鼠脑损伤后松果体Clock mRNA、Per2 mRNA表达和血浆褪黑素水平变化

目的比较缺氧缺血性脑损伤（HIBD）模型组与对照组的新生大鼠松果体中Clock mRNA和Per2 mNRA表达与血浆褪黑素（MLT）的变化。方法7日龄新生Sprague-Dawley大鼠,随机分为2组（每组36只）。HIBD模型组按改良Levine法建立。用半定量逆转录聚合酶链反应（RT-PCR）和放免技术分别测定并比较缺氧缺血后0、2、12、24、36、48h松果体中Clock mRNA和Per2 mRNA的相对表达量和血浆MLT水平。结果HIBD组和对照组Clock mRNA表达量差异均无统计学意义（P〉0.05）;Per2mRNA的表达在HIBD后24h开始下降,在36h和48h显著低于对照组（P〈0.01）;HIBD导致外周血MLT水平12h开始下降,24h降至谷底,48h恢复。结论钟基因Clock mRNA和下降的Per2mRNA表达以及血浆MLT可能在缺氧缺血性脑损伤的发生发展中起重要的作用。

Clock and Per2 mRNA expression in the pineal gland and the change in plasma melatonin of neonatal rats with hypoxic-ischemic brain damage

Objectives To elucidate the molecular mechanism of hypoxia-ischemia brain damage(HIBD)in neonatal rats.Methods 7 day-old Sprague-Dawley rats were randomly and averagely divided into 2 groups,HIBD group and sham-operated group(n = 36 in each group).HIBD models were set up by using modified Levine protocol.Animals were euthanized at 0,2,12,24,48 hrs afterwards and RNA was extracted from the pineal gland.Semi-quantitative RT-PCR was used to detect mRNA expression of Clock and Per2.Plasma level of melatonin was determined by radioimmunoassay.Results(1)There was no significant difference of Clock mRNA between HIBD group and sham-operated group(P > 0.05).(2)Per2 mRNA expression at 24 hrs after HIBD began to decline and was significantly lower than that of the sham-operated group at 36 and 48 hrs after HIBD(P < 0.01=.(3)The plasma levels of melatonin at 12 and 24 hrs after HIBD were significantly lower than that of the sham-operated group.The level of plasma melatonin recovered at 48 hrs after HIBD.Conclusions The changes on Clock and Per2 mRNA expression and plasma melatonin may play an important role in the pathogenesis of HIBD.