Institute of Clinical Medicine, National Cheng Kung University, Medical College and Hospital, Tainan, Taiwan.
Stroke. 2012 Feb;43(2):491-8. doi: 10.1161/STROKEAHA.111.629931. Epub 2011 Nov 10.
Neurovascular damage, including neuronal apoptosis and blood-brain barrier (BBB) damage, and microglia activation account for the hypoxic-ischemia (HI) susceptibility in neonatal brain. The p53 upregulation is involved in apoptosis, endothelial cell damage, and microglia activation. We hypothesized that underweight induced by dietary restriction (DR) protects against HI in rat pups by attenuating p53-mediated neurovascular damage.
Male rat pups were grouped as normal litter (NL) size (12 pups/dam), DR (18 pups/dam), and extreme DR (24 pups/dam) from postnatal day 1 and subjected to HI on postnatal day 7. Immunohistochemistry and immunoblotting were used to determine p53, phospho-murine double minute-2, caspases, BBB damage and microglia activation, and immunofluorescence to determine the cellular distribution of p53. Pharmacological approaches were used to regulate p53.
The NL, DR, and extreme DR pups had similar TUNEL-positive cells and caspases on postnatal day 7 and comparable learning performance at adulthood. After HI, the DR-HI, but not extreme DR-HI, pups had significantly lower p53, higher phospho-murine double minute-2, lower cleaved caspases, less BBB damage and microglia activation, and less brain volume loss than NL-HI pups. In NL-HI pups, p53 expression was located mainly in the neurons, endothelial cells, and microglia. The p53 blockage by pifithrin-α in NL-HI pups decreased apoptosis, BBB damage, and microglia activation, and was neuroprotective. In contrast, upregulating p53 by nutlin-3 in DR-HI pups increased apoptosis, BBB damage, and microglia activation, and worsened brain damage.
Moderate DR, but not extreme DR, reduces p53-mediated neurovascular damage after HI and confers long-term protection in neonatal brain.
神经血管损伤，包括神经元凋亡、血脑屏障（BBB）损伤和小胶质细胞激活，是新生儿脑缺氧缺血（HI）易感性的原因。p53 的上调参与了细胞凋亡、内皮细胞损伤和小胶质细胞激活。我们假设，饮食限制（DR）引起的体重不足通过减轻 p53 介导的神经血管损伤来保护新生大鼠免受 HI 的影响。
雄性大鼠幼崽从出生后第 1 天起分为正常窝仔（NL）大小（12 只/母鼠）、DR（18 只/母鼠）和极端 DR（24 只/母鼠），并在出生后第 7 天接受 HI。免疫组织化学和免疫印迹用于确定 p53、磷酸化鼠双微体 2、半胱天冬酶、BBB 损伤和小胶质细胞激活，免疫荧光用于确定 p53 的细胞分布。采用药理学方法调节 p53。
NL、DR 和极端 DR 幼崽在出生后第 7 天具有相似的 TUNEL 阳性细胞和半胱天冬酶，并且在成年时具有相当的学习能力。HI 后，DR-HI 而不是极端 DR-HI 幼崽的 p53 显著降低，磷酸化鼠双微体 2 升高，裂解半胱天冬酶降低，BBB 损伤和小胶质细胞激活减少，脑体积损失减少，与 NL-HI 幼崽相比。在 NL-HI 幼崽中，p53 表达主要位于神经元、内皮细胞和小胶质细胞中。在 NL-HI 幼崽中，p53 阻断剂 pifithrin-α 减少了细胞凋亡、BBB 损伤和小胶质细胞激活，并具有神经保护作用。相反，在 DR-HI 幼崽中上调 p53 增加了细胞凋亡、BBB 损伤和小胶质细胞激活，并加重了脑损伤。
适度的 DR，而不是极端的 DR，可减少 HI 后 p53 介导的神经血管损伤，并在新生儿脑内提供长期保护。
