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背景:研究证实,热休克蛋白70家族的蛋白质对细胞有保护作用。氯胺酮可导致患者出现幻觉、谵妄等精神症状,可对大鼠边缘系统神经元产生损害,在这些受损的神经元内用免疫组化染色方法可检测到热休克蛋白70的表达。目的:观察不同剂量的氯胺酮在不同年龄大鼠海马中诱导热休克蛋白70的表达,探讨氯胺酮对神经损害的作用。设计:随机对照实验。单位:四川大学华西医院麻醉学与危重医学教研室。材料:实验于2000-01/05在四川大学华西医院麻醉学与危重医学教研室实验室完成。选择SD大鼠70只,雌雄不限,清洁级。方法:35只成年SD大鼠随机分为对照组和氯胺酮20.0,40.0,60.0,80.0,100.0,120.0mg/kg6个实验组,每组5只,分别给予生理盐水和氯胺酮20.0,40.0,60.0,80.0,100.0,120.0mg/kg腹腔内注射。另取0～10,11～20,21～30,31～45,46～60,61～90,91～120d年龄阶段大鼠35只,每个年龄段5只,分别腹腔内注射氯胺酮80.0mg/kg。给药后正常喂养24h后,在麻醉状态下快速断头取脑,于海马取5μm冠状切面切片,应用免疫组化染色检测大鼠海马中热休克蛋白70的表达。主要观察指标:大鼠海马热休克蛋白70阳性细胞百分率、密度和灰度值。结果:70只大鼠均进入结果分析。①不同剂量氯胺酮对大鼠脑海马区热休克蛋白70表达:对照组,20.0,40.0,60.0,80.0,100.0,120.0mg/kg剂量氯胺酮组诱导热休克蛋白70表达的阳性细胞密度分别为0,8.12±1.82,27.07±5.98,45.35±5.84,78.51±7.34,74.16±8.17,60.84±6.27。可见氯胺酮剂量在80.0mg/kg以内,随剂量的增加,热休克蛋白70阳性细胞密度显著增加(P<0.01);氯胺酮剂量在80.0mg/kg以上,随剂量的增加,热休克蛋白70阳性细胞密度显著降低(P<0.01)。②氯胺酮对不同年龄段大鼠脑海马区热休克蛋白70表达:20d以下的幼鼠神经细胞热休克蛋白70阳性细胞密度为0;在21～30d,31～45d,46～60d,61～90d大鼠海马中热休克蛋白70阳性细胞密度分别为34.17±6.18,55.42±4.80,78.51±7.34,83.16±11.10,与前一年龄组相比,随着年龄的增加,热休克蛋白70阳性细胞密度显著增加(P<0.01);61～90d和91～120d大鼠海马中热休克蛋白70阳性细胞密度分别为83.16±11.10和85.83±9.33(P>0.05)。结论:氯胺酮可诱导热休克蛋白70在大鼠脑海马区表达,提示海马区的神经元可能受到损害;随剂量的增加,其损害作用加强;氯胺酮对成年大鼠的脑损害作用大于幼鼠。
Background: Studies confirm that proteins from the heat shock protein 70 family have a protective effect on cells. Ketamine can cause psychiatric symptoms such as hallucinations and delirium in patients, which can damage the peripheral neurons in rats. Immunohistochemical staining can detect the expression of heat shock protein 70 in these damaged neurons. OBJECTIVE: To observe the effects of different doses of ketamine on the expression of heat shock protein 70 (HSP70) in hippocampus of rats of different ages, and to explore the effect of ketamine on nerve damage. Design: Randomized controlled experiment. Unit: West China Hospital of Sichuan University Department of Anesthesiology and Critical Care Medicine. MATERIALS: Experiments were performed at the Laboratory of Anesthesiology and Critical Care Medicine, West China Hospital, Sichuan University from January 2000 to January 2005. Select 70 SD rats, male or female, clean level. Methods: Thirty-five adult Sprague-Dawley rats were randomly divided into control group and ketamine 20.0, 40.0, 60.0, 80.0, 100.0 and 120.0 mg / kg six experimental groups with 5 rats in each group and received normal saline and ketamine 20.0, 40.0, 60.0, 80.0, 100.0, 120.0 mg / kg intraperitoneally. Another take 0 ~ 10,11 ~ 20,21 ~ 30,31 ~ 45,46 ~ 60,61 ~ 90,91 ~ 120d age rats 35 rats, each of five age groups were intraperitoneal injection of ketamine 80.0mg / kg. After normal feeding for 24 h, the brains were rapidly decapitated under anesthesia and the corpus slices were taken from the hippocampus. The hippocampal heat shock protein 70 expression was detected by immunohistochemistry. MAIN OUTCOME MEASURES: Percentage, density and gray value of heat shock protein 70 positive cells in hippocampus of rats. Results: All 70 rats were involved in the result analysis. (1) The expression of HSP70 in hippocampus of rats with different doses of ketamine: In the control group, the positive cell density of heat shock protein 70 induced by ketamine in the doses of 20.0,40.0,60.0,80.0,100.0,120.0mg / kg was 0, 8.12 ± 1.82, 27.07 ± 5.98, 45.35 ± 5.84, 78.51 ± 7.34, 74.16 ± 8.17, 60.84 ± 6.27. Ketamine dose of 80.0mg / kg or less, with the dose increased, heat shock protein 70 positive cell density increased significantly (P <0.01); ketamine dose of 80.0mg / kg or more, with increasing doses of heat shock protein 70 positive cells The density was significantly lower (P <0.01). ②Ketamine on the expression of heat shock protein 70 in hippocampus of rats of different age groups: The density of heat shock protein 70 positive cells of neurons in young rats under 20 days was 0; at 21 ~ 30d, 31 ~ 45d, 46 ~ 60d, 61 ~ 90d The density of HSP70 positive cells in hippocampus of rats was 34.17 ± 6.18,55.42 ± 4.80,78.51 ± 7.34,83.16 ± 11.10, respectively. Compared with the previous age group, the density of heat shock protein 70 positive cells (P <0.01). The positive cell density of heat shock protein 70 in hippocampus of rats in 61-90 d and 91-120 d were 83.16 ± 11.10 and 85.83 ± 9.33, respectively (P> 0.05). CONCLUSION: Ketamine can induce the expression of heat shock protein 70 in hippocampus of rat hippocampus, suggesting that neurons in hippocampus might be damaged. With the increase of dose, ketamine could enhance the damage of brain. Ketamine exerted a greater effect on brain damage in adult rats than in young rats.