羟丁酸钠对缺血缺氧性脑损伤新生大鼠大脑皮层神经细胞凋亡的影响

Sodium hydroxybutyrate decreases hypoxic-ischemic insult-induced neuronal apoptosis in neonatal rat cortex

目的观察羟丁酸钠对缺血缺氧性脑损伤新生大鼠大脑皮层神经细胞凋亡的影响。方法新生7 d SD大鼠随机分为假手术组(S组)、生理盐水对照组(C组)和羟丁酸钠组(γ1、γ2和γ3 组)。每组按HI(缺血缺氧)后不同时间点进一步分为1 h、3 h、1 d、3 d、7 d 5个亚组(n=6)。按Rice法制作缺血缺氧性脑损伤模型。C、γ1、γ2和γ3组HI后即腹腔分别注射生理盐水0．2ml/10g、羟丁酸钠 50、100、200 mg/kg,3次/日;S组术后吸空气2 h,腹腔注射生理盐水0．2 ml/10 g,3次/日。TUNEL染色法检测HI后各时间点大脑皮层凋亡神经细胞。结果 HI后1 h-7 d,C、γ1、γ2、γ3组凋亡神经细胞数高于S组(P<0．05),且于HI后1 d达高峰;HI后3 h-3 d,C、γ3组凋亡神经细胞数多于γ1、γ2组(P <0．05),而C组与γ3组之间凋亡神经细胞数差异无统计学意义(P>0．05);HI后7 d,γ1组凋亡神经细胞数多于γ2组(P<0．05)。结论 50、100 mg/kg羟丁酸钠能抑制缺血缺氧性脑损伤新生大鼠大脑皮层神经细胞凋亡,且100 mg/kg效果较好。

Objective To investigate the effects of sodium hydroxybutyrate （γ-OH） on neuronal apoptosis in neonatal rat cortex induced by hypoxic-ischemic （HI） insult. Methods One-hundred and fifty 7-day old newborn SD rats were randomly assigned to one of 5 groups （ n = 30 each） ： sham operation group （A） ; HI ＋ normal saline （NS） group （B） and three HI ＋ γ-OH groups （C, D, E）. HI was induced by ligation of left common carotid artery followed by 2 h inhalation of hypoxic air （8% 02 92% N2 ）. In sham operation group （A） left common carotid artery was exposed but not ligated and no hypoxic air was inhaled after operation. In group B （HI ＋ NS） NS 0.2 ml·10 g^-1 was injected intrapefitoneally （IP） t. i. d immediately after HI until the animals were killed; whereas in HI＋ γ-OH groups γ-OH 50 （C） or 100 （D） or 200 （E） mg·kg^-1 was injected IP instead of NS. Six animals were killed at 1 h, 3 h, 1 d, 3 d and 7 d in each group and brains were removed. The number of apoptotic neurons in the left cortex was detected using TUNEL staining technique. Results The number of apoptotic neurons at 1 h-7 d after HI was significantly greater in group B, C, D and E than in group A （sham operation）. The expression of apoptosis positive neurons reached the peak at 1 day after HI. The number of apoptotic neurons at 3 h-3 d was significantly greater in group E （γ-OH 200 mg·kg^-1 ） than in group C and D （γ- OH 50 and 100 mg·kg^-1）. There was no significant difference in the number Of apoptotic neurons between group B （HI ＋ NS） and E （ HI ＋ γ-OH 200 mg·kg^- 1 ）. Conclusion Sodium hydroxybutyrate 50 and 100 mg·kg^- 1 can attenuate neuronal apoptosis in neonatal rat cortex induced by hypoxic-ischemic insult.