Abstract

Aim of the study

Hypoxic-ischemic encephalopathy (HIE) is a major cause of newborn brain injury. Apoptosis and necroptosis are two forms of cell death which may occur in HIE but reported data are yet limited. This study investigates the expression of receptor interacting protein kinase (RIPK) 1 and 3, and caspase3, the key modulators of necroptosis and apoptosis, respectively, in a model of HIE to determine whether both forms of cell death occur in the corresponding brain regions.

Materials and methods

Postneonatal day 7 Sprague-Dawley rats were subjected to right carotid artery ligation followed by hypoxia or subjected to skin incision under surgical anesthesia without ligation and hypoxia. Neuroglioma (H4) cell was cultured and subjected to 24 h hypoxic insults. Necrostatin-1, a RIPK1 inhibitor, was administered in both in vivo and in vitro settings before insult.

Results

After hypoxic-ischemic insults, both RIPK1 and RIPK3 expression were significantly increased in the region of hippocampal dentate gyrus in the injurious hemisphere. However, cleaved caspase3 was significantly increased in the hippocampal cornu ammonis 1 region in the injurious hemisphere. After hypoxic insults, RIPK1 and RIPK3 expression was also found in H4 cells. In addition, it was identified that the increased RIPK1 and RIPK3 can be inhibited by necrostatin-1 in both in vivo and in vitro.

Conclusions

These data indicated that apoptosis and necroptosis occur in different brain regions of hippocampus in a model of HIE which may suggest that strategies to prevent each form of neuronal death is valuable to be developed.

中文翻译：

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缺氧窒息大鼠海马不同脑区发生凋亡和坏死

摘要

研究目的

缺氧缺血性脑病 (HIE) 是新生儿脑损伤的主要原因。细胞凋亡和坏死性凋亡是 HIE 中可能发生的两种细胞死亡形式，但报告的数据尚有限。本研究调查了 HIE 模型中受体相互作用蛋白激酶 (RIPK) 1 和 3 以及 caspase3（分别是坏死性凋亡和细胞凋亡的关键调节剂）的表达，以确定这两种形式的细胞死亡是否都发生在相应的大脑区域。

材料和方法

新生儿后第 7 天对 Sprague-Dawley 大鼠进行右颈动脉结扎，然后缺氧或在无结扎和缺氧的手术麻醉下进行皮肤切口。培养神经胶质瘤 (H4) 细胞并进行 24 小时缺氧刺激。Necrostatin-1，一种 RIPK1 抑制剂，在侮辱前在体内和体外环境中给药。

结果

缺氧缺血性损伤后，损伤半球海马齿状回区域的 RIPK1 和 RIPK3 表达均显着增加。然而，在损伤半球的海马角 1 区域中裂解的 caspase3 显着增加。缺氧损伤后，在 H4 细胞中也发现了 RIPK1 和 RIPK3 的表达。此外，已经确定增加的 RIPK1 和 RIPK3 可以在体内和体外被 necrostatin-1 抑制。

结论

这些数据表明，在 HIE 模型中，海马的不同脑区发生细胞凋亡和坏死性凋亡，这可能表明预防每种形式的神经元死亡的策略值得开发。