Objective: To investigate the effect of mild hypothermia combined with hydrogen sulfide on hippocampal endoplasmic reticulum stress (ERS) after global cerebral ischemia-reperfusion (I/R) injury. Methods: Sixty healthy male Sprague-Dawley rats, 8-10 week old, weighing 280-320 g, were randomly divided into 5 groups (n=12) using a random number table: sham operation group (group Sham), global cerebral I/R group (group I/R), hydrogen sulfide group (group H(2)S), mild hypothermia group (group MH) and hydrogen sulfide + mild hypothermia group (group H(2)S+ MH). Cardiac arrest was induced with transoesophageal cardiac pacing followed by cardiopulmonary resuscitation to establish the global cerebral I/R model. The administration regimen for sodium hydrosulfide (NaHS) was as follows: Sodium hydrosulfide was intraperitoneal injection as a bolus of 2.5 mg/kg immediately restoration of spontaneous circulation. The implementation of mild hypothermia: wipe the body surface of rats with ethanol immediately after restoration of spontaneous circulation, and reduce the rectal temperature to 32-34 ℃ within 15 min, and maintain 6 h with the ice bag. At 72 h of reperfusion, neurological deficit was scored, and the rats were sacrificed (Neurological Deficit Scores, NDS), the expression of glucose-regulated protein 78 (GRP78), CHOP and Caspase-12 were detected by Western blot. After reperfusion 72 h, the hippocampal tissue were removed and stained with haematoxylin and eosin to examine the pathological findings in hippocampal CA1 area (under microscope). The apoptosis rate of hippocampal CA1 area cells was detected by TUNEL staining and the apoptosis index was calculated. Results: The expression levels of endoplasmic reticulum stress marker, GRP78, CHOP and Caspase-12, were upregulates during the global cerebral ischemia reperfusion injury, indicating activation of severe endoplasmic reticulum stress. The GRP78 contents of Sham group, I/R group, H(2)S group, MH group and H(2)S+ MH group were as follows: GRP78: 0.11±0.03, 1.11±0.10, 0.67±0.09, 0.66±0.08, 0.48±0.04, CHOP contents: 0.16±0.03, 1.60±0.11, 1.39±0.09, 1.34±0.08, 1.13±0.09, Caspase-12 contents: 0.09±0.02, 0.87±0.08, 0.65±0.08, 0.59±0.06, 0.45±0.06, the differences were statistically significant (F=147.569, 264.983, 119.356, all P<0.01). The apoptosis index of Sham group, I/R group, H(2)S group, MH group and H(2)S+ MH group were as follows: (1.83±0.75)%, (53.17±4.62)%, (35.17±2.14)%, (32.67±2.25)%, (17.83±2.79)%, the differences were statistically significant (F=284.962, P<0.01). The neurological deficit scores of Sham group, I/R group, H(2)S group, MH group and H(2)S+ MH group were as follows: 0%, (76±9)%, (54±5)%, (47±6)%, (35±6)%, the differences were statistically significant(F=135.218, P<0.01). Conclusion: Mild hypothermia combined with hydrogen sulfide alleviates hippocampal endoplasmic reticulum stress after global cerebral ischemia-reperfusion, and the combined effect is better than that of a single application.
目的： 观察浅低温联合硫化氢对全脑缺血再灌注(I/R)损伤后海马内质网应激(ERS)的影响。 方法： 清洁级健康雄性SD大鼠60只，8～10周龄，体质量280～320 g，采用随机数字表法分为5组(n＝12)：假手术组(Sham组)、全脑缺血再灌注组(I/R组)、硫化氢组(H(2)S组)、浅低温组(MH组)、硫化氢＋浅低温组(H(2)S＋MH组)。采用经食管心脏起搏法诱发心跳骤停并行心肺复苏制备大鼠全脑缺血再灌注损伤模型。硫氢化钠(NaHS)的给药方案：于自主循环恢复即刻腹腔注射硫氢化钠2.5 mg/kg；浅低温的实施：于自主循环恢复即刻用乙醇擦拭大鼠体表，配合冰袋15 min内将直肠温度降至32～34 ℃，维持6 h。于再灌注72 h时行神经功能缺陷评分(NDS)，处死大鼠后取海马组织，采用蛋白免疫印迹(Western blot)法检测葡萄糖调节蛋白78(GRP78)、转录因子C /EBP同源蛋白(CHOP)和Caspase－12的表达；于再灌注72 h时取海马组织，行HE染色，光镜下观察海马CA1区病理学结果；采用原位DNA末端转移酶法(TUNEL)染色检测海马CA1区细胞凋亡情况，计算细胞凋亡指数(AI)。 结果： 全脑缺血再灌注损伤可诱导内质网应激标志蛋白GRP78、CHOP和Caspase－12的表达显著增高，提示严重的内质网应激被激活。Sham组、I/R组、H(2)S组、MH组、H(2)S＋MH组的GRP78含量分别为0.11±0.03、1.11±0.10、0.67±0.09、0.66±0.08、0.48±0.04，CHOP的含量分别为0.16±0.03、1.60±0.11、1.39±0.09、1.34±0.08、1.13±0.09, Caspase－12的含量分别为0.09±0.02、0.87±0.08、0.65±0.08、0.59±0.06、0.45±0.06，差异均具有统计学意义(F＝147.569、264.983、119.356,均P<0.01)。Sham组、I/R组、H(2)S组、MH组、H(2)S＋MH组的细胞凋亡指数分别为(1.83±0.75)%、(53.17±4.62)%、(35.17±2.14)%、(32.67±2.25)%、(17.83±2.79)%，差异有统计学意义(F＝284.962, P<0.01)。Sham组、I/R组、H(2)S组、MH组、H(2)S＋MH组的神经功能缺陷评分分别为0%、(76±9)%、(54±5)%、(47±6)%、(35±6)%，差异有统计学意义(F＝135.218, P<0.01)。 结论： 浅低温联合硫化氢减轻全脑缺血再灌注后海马内质网应激，联合效果优于单独应用。.
Keywords: Endoplasmic reticulum stress; Hydrogen sulfide; Mild hypothermia; Reperfusion injury, brain.