早期应用高压氧治疗对颅脑损伤大鼠神经元凋亡的干预及环氧化酶2表达的变化

Intervention of hyperbaric oxygen treatment for the neuronal apoptosis and the expression of cyclocygenase 2 in rats with head injury in an early period

目的:观察颅脑损伤大鼠早期应用高压氧治疗后神经元凋亡情况以及环氧化酶2表达的变化。方法:实验于2004-06/2005-06在白求恩医科大学病理科完成。①选择成年SD雄性大鼠60只,随机数字表法分为高压氧治疗组、损伤对照组、假手术组,20只/组。②高压氧治疗组、损伤对照组大鼠建立颅脑损伤模型,开放骨窗后采用自由落体法造成右顶叶较为一致的脑挫裂伤,冲击力为50g×13cm。假手术组不造模,只开放骨窗,不给予打击,且于术后立即处死。③高压氧治疗组大鼠于脑损伤后0.5h置于动物氧舱内,用纯氧洗舱10min后,匀速加压10min至0.2MPa,稳压40min,间断性舱内给氧以维护纯氧状态,随后匀速减压20min至常压,使大鼠在常压下呼吸空气10min后重复上述过程1次,此为1次治疗。40min后重复上述治疗1次,2次/d,持续至伤后48h。损伤对照组不进行高压氧治疗。高压氧治疗组、损伤对照组大鼠均在受伤后48h处死。④取损伤周边部位的脑组织,TUNEL染色检测神经元细胞的凋亡情况,ABC法免疫组化测定环氧化酶2的表达。结果:60只大鼠均进入结果分析。①伤后48h各组大鼠受损脑组织周围环氧化酶2的表达:与假手术组比较,高压氧治疗组、损伤对照组环氧化酶2的表达均明显升高[(16.70±58.85)×103,(23.27±71.26)×103,(37.97±88.95)×103,P<0.05],但高压氧治疗组升高幅度明显低于损伤对照组(P<0.05)。②伤后48h各组大鼠受损脑组织周围细胞凋亡情况:与假手术组比较,高压氧治疗组、损伤对照组细胞凋亡率均明显升高[(12.59±1.39)%,(13.12±2.46)%,(44.69±7.65)%,P<0.05],但高压氧治疗组升高幅度明显低于损伤对照组(P<0.05)。结论:颅脑损伤大鼠存在神经元凋亡增加的现象,高压氧通过下调环氧化酶2的表达减少神经元凋亡的发生。

AIM： To observe neuron apoptosis and change of cycloxygenase 2 expression after hyperbaric oxygen treatment in head injury rats in an early period. METHODS： The experiment was performed at the Department of Pathology, Norman Bethune University of Medical Sciences from June 2004 to June 2005. ①A total of 60 adult SD male rats were selected and divided into 3 groups randomly： hyperbaric oxygen treatment group, injured control group and sham operation group with 20 in each group. ②Head injury models were established in ihe hyperbaric oxygen treatment group and injured control group. After opening bone window, consistent contusion and laceration of brain at fight parietal lobe was established with free fall method, with the impact of 50 g×13 cm. Sham operation group did not establish models, only open bone window, no coup, and the rats were killed immediately after operation. ②Thc rats in the hyperbaric oxygen treatment group were put in animal oxygen chamber after head injury for 0.5 hour. After washing the chamber with pure oxygen for 10 minutes, compression evenly to 0.2 MPa for 10 minutes, voltage stabilitation for 40 minutes. Discontinuous oxygen was given to chamber in order to maintain pure oxygen state, and then even decompression for 20 minutes was performed to normal pressure. Above-mentioned process was replicated once after breathing for 10 minutes under normal pressure, which was a therapy. Forty minutes later, above-mentioned therapy was conducted once, twice a day till hour 48 after injury. Those in the injured control group did not receive hyperbaric oxygen treatment. The rats in the hyperbaric oxygen treatment group and injured control group were killed at hour 48 after injury. ③Brain tissue around injured region was obtained. Apoptosis of neurons was measured with TUNEL staining. The expression of cyclocygenase 2 was examined with ABC immunohistochemical method. RESULTS： A total of 60 rats were involved in the result analysis. ①Expression of cyclocygenase 2 around injured brain tissues in each group at hour 48 after injury： Compared with the sham operation group, its expression was significantly higher in the hyperbaric oxygen treatment group and injured control group [（16.70±58.85） ×10^3, （23.27±71.26）× 10^3, （37.97±88.95）×10^3,p 〈 0.05], but the increasing range in the hyperbaric oxygen treatment group was markedly lower than that in the injured control group （P 〈 0.05）.② Cell apoptosis of injured brain tissue in each group at hour 48 after operation： Compared with the sham operation group, it was increased remarkably in the hyperbaric oxygen treatment group and injured coiatrol group [（ 12.59±1.39）%, （ 13.12±2.46）%, （44.69±7.65）% ,P 〈 0.05], but the increasing range in the hyperbaric oxygen treatment group was markedly lower than that in the injured control group （P 〈 0.05 ）. CONCLUSION： The increase of apoptosis appears in neurons of rats with head injury. Hyperbaric oxygen can delay the occurrence of apoptosis in neurons through down-regulating the expression of cyclocygenase 2.