注射IL-1β后大鼠下丘脑室旁核内CRH/AVP基因转录的动态变化

The dynamics of CRH and AVP gene transcription within the paraventricular hypothalamic nucleus after injection of IL-1β into rats

目的探讨IL-1β对下丘脑室旁核(PVN)内促肾上腺皮质素释放激素(CRH)和血管加压素(AVP)基因转录的影响。方法麻醉下于Wistar大鼠右心房内留置导管,48h后将清醒大鼠分为5组,分别于右心房内注射IL-1β(1.4μg/kg)或生理盐水(300μl)后于15、120min后断头,以及无任何处置的空白对照组。取各组大鼠躯干血,采用放射免疫分析法测定促肾上腺皮质激素(ACTH)和AVP的浓度。利用[35S]UTP、[35S]CTP双标记RNA探针采用原位杂交组织化学方法检测各组大鼠PVN内CRH hnRNA、CRH mRNA和AVP hnRNA、AVP mRNA的表达。结果与空白对照组相比,血浆ACTH和AVP浓度均在注射IL-1β15min后显著增加(P<0.01),在120min后恢复正常。CRH hnRNA表达水平在注射IL-1β15min后显著增加(P<0.01),120min后恢复正常;CRH mRNA表达水平在注射IL-1β120min后显著增加(P<0.01)。小细胞内AVP hnRNA表达水平在注射IL-1β15min后显著增加(P<0.01),且持续增加至120min后,而大细胞内AVP hnRNA表达水平在注射IL-1β120min后显著增加(P<0.01);小细胞内AVP mRNA表达水平在注射IL-1β120min后显著增加(P<0.01),而大细胞内AVP mRNA表达水平在注射IL-1β15和120min后均无明显改变。结论共存于小细胞内的CRH、AVP基因转录的调控机制不同,而共存于大、小细胞内的AVP基因转录的调控机制也完全不同,表明不同细胞内同一基因转录的动态变化不同。

Objective To examine the effects of cytokine IL-1β on CRH and AVP gene transcription in the paraventricular nucleus of the hypothalamus. Methods Under anesthesia the catheter were implanted into the right atria of rats. 48 hours after the surgery, the conscious rats were divided into 5 groups. IL-1β （1.4μg/kg） or saline （300μl） was injected into the vein of conscious rats, rats were decapitated 15, 120 min after IL-1β injection. Take trunk blood of rats, plasma ACTH and AVP were measured by RIA. The expression of CRH hnRNA, CRH mRNA, AVP hnRNA, and AVP mRNA were detected by [35S]UTP, [35S]CTP double lablled in situ hybridization and autoradiograph. Results Plasma ACTH and AVP reached a peak （P 〈 0.01） at 15 min after IL-1β injection, then returned to the basal level by 120 min. Expression of CRH hnRNA increased markedly 15 min after IL-1β injection （P 〈 0.01）, then returned by 120 rain. Expression of AVP hnRNA in the parvocellular division increased 15 min after IL-1β injection （P 〈 0.01）, and furthermore this increase continued until to 120 min after IL-1β injection. After IL-1β injection, expression of CRH mRNA and AVP mRNA in the parvocellular division increased at 120 min （P 〈 0.01）. After IL-1β injection, expression of AVP hnRNA in the magnocellular division increased at 120 min （P 〈 0.01）, but expression of AVP mRNA in the same division was not significantly different from the basal value at any time. Conclusion These results show the dynamics of CRH and AVP gene transcription in the paraventricular after the IL-1β injection into the vein, suggest that regulation of CRH and AVP gene transcription in the parvocellular division is different, and that regulation ofAVP gene transcription in the magnocellular division is different from in the parvocellular division too.