羟丁酸钠在大鼠海马脑片缺氧/复氧损伤中的保护作用机制

目的：研究羟丁酸钠（SO）在大鼠海马脑片缺氧/复氧（H/R）损伤中的保护作用,揭示SO在缺血性脑损伤中的保护作用机制。方法：采用大鼠海马脑片H/R损伤模型。设正常对照组,H/R组,SO1、10、100μmol/L组,NCS-382100μmol/L＋SO100μmol/L（NCS-382＋SO）组、NCS-356100μmol/L（NCS-356）组。测定脑片孵育液中乳酸脱氢酶（LDH）释放率,γ-氨基丁酸（GABA）、谷氨酸（Glu）含量;脑片进行TTC染色计算组织损伤百分率;HE染色观察组织病理形态学变化,流式细胞仪测定细胞内钙;酶组织化学法检测一氧化氮合酶（NOS）的表达。结果：SO明显降低H/R海马脑片LDH释放率（P〈0.01）,提高TTC染色的A490值,降低组织损伤百分率（P〈0.01）,升高GABA/Glu比值（P〈0.01）,减轻H/R所致的组织病理损伤。H/R组脑片细胞内钙荧光强度和NOS阳性神经元明显高于正常对照组（P〈0.01）;SO100μmol/L组、NCS-356组细胞内钙荧光强度较H/R组显著减弱（P〈0.01）,NOS阳性神经元的数目明显减少（P〈0.01）。用γ-羟基丁酸（GHB）受体选择性阻断剂NCS-382后再使用SO,细胞内钙荧光强度、NOS阳性神经元的数目均接近H/R组。结论：SO对大鼠海马脑片H/R损伤有明显的保护作用,其机制可能与升高GABA/Glu比值,激动GHB受体抑制细胞内钙的增高及NOS的表达有关。

Protective effects of sodium oxybate on hypoxia/reoxygenation injury of hippocampal slices in rats

AIM： To study the protective effects of sodium oxybate（SO） on hypoxia/reoxygenation injury of hippocampal slices of rats and investigate its protective mechanism SO to ischemic cerebral injury. METHODS： Experimental model of hypoxia/reoxygenation injury of hippocampal slices of rats was adopted. Slices were equally divided into seven groups： control group, hypoxia/reoxygenation （H/R） group, SO1, 10, 100 μmol/L group, NCS-382 γ-hydroxybutyric acid （GHB） receptors antagonist ] 100 μmol/L combined with SO100 μmol/L （NCS-382 ＋ SO100） group, NCS- 356 （GHB receptors agonist） 100 μmol/L group. LDH release rate and gamma-aminobutyric acid （GABA） and glutamate （Glu） content in incubation fluid of hippocampal slices were measured. Tissue injury in slices was detected by TIC staining method. The Changes of histomorphology by HE staining were observed as well. Changes of intracellular calcium by flow cytometry and the expression of nitric oxide synthase by enzymohistochemistry method were studied. RESULTS： Hypoxia/ reoxgenation caused an increase in LDH release rate, a decrease in TTC staining, a decline of GABA/Glu ratio and tissue injury obviously, while pretreatment with SO was able to reverse the indexes mentioned above（ P 〈 0.01 ）. Fluorescence intensity of intracellular calcium and the number of NOS positive neurons in H/R group were higher than those in the control group （P 〈 0.01 ）. However, fluorescence intensity of intracellular calcium （P 〈 0.01 ） in SO100 and NCS-356 groups was lower than that in H/R group, were the number of NOS positive neurons was reduced obviously （P 〈 0.01）. Using SO after GHB receptors antagonist NCS- 382, fluorescence intensity of intracellular calcium and the number of NOS positive neurons were similar to H/ R group. CONCLUSION： SO can protect hippocampal slices subjected to hypoxia/reoxygenation injury significantly in rots. The protective mechanism of SO may related to the increase of GABA/Glu ratio, the reducing of