去甲肾上腺素在高原大鼠脑水肿形成中作用的实验研究

目的 探讨去甲肾上腺素（noradrenalin，NA）在高原脑水肿形成中的作用。方法 建立大鼠模拟高原7000m低氧低压模型。NA对照组大鼠分别给予NA 0mg／kg（生理盐水0．2m1）（正常对照）、1mg／kg（LNA）、2mg／kg（MNA）及5mg／kg（HNA）腹腔注射；NA高原组大鼠分别给予NA0mg／kg（生理盐水0．2m1）（高原对照）、1mg／kg（hLNA）、2mg／kg（hMNA）及5mg／kg（hHNA）腹腔注射后迅速置入低压舱内。应用脑干湿重比率法定量脑水肿情况，应用荧光素钠透过率测定BBB通透性。结果 正常对照、LNA、MNA及HNA组之间脑含水率差异无统计学意义（P〉0．05）。高原对照组脑含水率与正常对照组相比有明显增高，差异有统计学意义（P〈0．05），hLNA、hMNA及hHNA组与相应LNA、MNA及HNA组相比脑含水率差异有统计学意义（分别为P〈0．01，P〈0．01，P〈0．05）。hLNA组脑含水率与高原对照组相比差异无统计学意义（P〉0．05），hMNA及hHNA组脑含水率与高原对照组相比差异有统计学意义（P〈0．05）。正常对照、LNA及MNA之间NaF1差异无统计学意义（P〉0．05），HNA NaF1与正常对照组相比差异有统计学意义（P〈0．05）。高原对照组NaF1与正常对照组相比差异有统计学意义（P〈0．01），hLNA、hMNA及hHNA组与相应LNA、MNA及HNA组相比，NaF1均差异有统计学意义（分别为P〈0．01，P〈0．001，P〈0．001）。hLNA组NaF1与高原对照组相比差异无统计学意义（P〉0．05），hMNA及hHNA组NaF1与高原对照组相比差异有统计学意义（分别为P〈0．05，P〈0．01）。结论 在高原状态下去甲肾上腺素可使血脑屏障通透性显著增高，诱发高原脑水肿加重。

An experimental study on the role of noradrenalin in the formation of high altitude cerebral edema

Objective To investigate the role of noradrenalin in the formation of high altitude cerebral edema.Methods Wistar rats given various dosage of noradrenalin peritoneally were exposed to low-pressure cabin for 24h and mimiced the high altitude of 7000m.The ratio of dry and wet brain weight was calculated and the sodium fluorescein leakage was calculated to evaluate the cerebral edema and the blood brain barrier permeability.Results In rats treated with low dosage of noradrenalin(LNE),middle dosage of noradrenalin(MNE) or high dosage of noradrenalin(HNE),the percentage of water containing in brain tissue was similar to that in normal control group.In rats exposed to simulated HA circumstance(HA group),the rate of water containing in the brain increased significantly(P<0.05).And in the HA groups treated with LNE,MNE or HNE,all the percentage of water containing increased significantly when compared with normal control group(P<0.01,P<0.01,P<0.05 respectively).The increase of water containing percentage in brain tissue in rats treated with MNE and HNE exposed to the simulated HA circumstance was significantly hihger than that in HA control group(P<0.05 respectively).The permeability coefficient of sodium fluorescein(NaFl) in normal BBB was very low.In rats treated with LNE and MNE,both the permeability coefficients were similar to those in normal group.While in rats treated with HNE,the permeability coefficient of NaFl increased significantly.In HA control rats the permeability coefficient of NaFl was significantly increased.And in the HA groups treated with LNE,MNE or HNE,all the permeability coefficients of NaFl increased significantly when compared with normal control group(P<0.01,P<0.001,P<0.001 respectively).The increase of permeability coefficients in rats treated with MNE and HNE exposed to the simulated HA circumstance was significantly hihger than that in HA control group(P<0.05,P<0.01 respectively).Conclusion It is suggested that noradrenalin may enhance the permeability of blood brain barrier and trigger the aggravation of high altitude cerebral edema.