高压氧对新生大鼠缺氧缺血脑组织中强啡肽含量的影响

Effect of hyperbaric oxygen therapy on dynorphin content in the brain subjected to hypoxic-ischemic brain injury in neonatal rats

目的观察高压氧治疗新生大鼠缺氧缺血性脑损伤(HIBI)后脑内强啡肽A1-13浓度的动态变化规律。方法7 d龄SD大鼠左侧颈总动脉结扎联合低氧吸入形成HIBI模型,在HIBI后施以高压氧治疗(A组),并设HIBI+常氧高压氮组(B组)、单纯HIBI组(C组)、假手术组(D组)和正常组(E组)。观察各组处理后不同时间左侧皮层、海马、纹状体和血浆强啡肽A1-13免疫活性物质(ir-DynA1-13)含量的变化。结果高压氧单次处理后,A组皮层和海马中ir-DynA1-13含量较B组含量均显著降低(P< 0．01),但皮层ir-DynA1-13含量较D组仍显著升高(P<0．05);7次高压氧处理后,A组皮层、海马中ir- DynA1-13含量较B组仍显著降低(P<0．05)。单次处理后与B或C组比较,A组血浆中ir-DynA1-13含量显著降低。结论强啡肽A1-13参与新生大鼠HIBI的病理生理过程,抑制中枢神经强啡肽A1-13水平的异常改变,是高压氧治疗新生大鼠HIBI的机制之一。

Objective To investigate the dynamic changes of contents of dynorphinA（1-13） when the hypoxic-ischemic brain injury （HIBI） was treated by hyperbaric oxygen therapy （HBO） in neonatal rats. Methods Seven-day-old SD rats were randomized into HIBI followed by HBO group （ HIBI ＋ HBO, A）, HIBI followed by normoxic hyperbaric nitrogen group （ B）, mere HIBI group （ C ）, sham-operated group （ D ）, and normal group （E）. HIBI was prepared by a permanent ligation of left common carotid artery followed by a 2.5 h inhalation of humidified 8% 02 ＋92% N2 at 37 ℃. After the injury, the pups were treated by HBO （A） or gas （B） once a day for a seven-day period or without （C）. Contents of dynorphinA（1-13） like immunoreactivity （ir- DynA（1-13）） in the left cortex, hippocampus and striatum as well as in the plasma were tested by radioimmunoassay one time and/or 7 d after the treatment. Results Contents of ir-DynA（1-13） were significantly decreased in group A compared with group B in the cortex and the hippocampus （ P 〈 0.01 ） but increased in the cortex when compared with group D after one-time process （ P 〈 0.05 ） after a bolus of HBO treatment. There was a decreased level of ir-DynA（1-13） in the cortex and the hippocampus in group A when compared with group B after 7-time process. After one-time process in the plasma, level of ir-DynA（1-13） in group A was also decreased compared with group B or C. Conclusions Present data suggest that dynorphinA（1-13） participates in the pathophysiological process of HIBI. One of the pathways of the beneficial effects of HBO on HIBI lies on the alleviation of the abnormal levels of dynorphin A（1-13） within the brain areas.