高压氧对鼠脑氧化氮合酶(NOS)阳性细胞分布的影响及NOS抑制剂的抗氧惊厥作用(论著)

The influence of HBO on NOsynthasepositive neurons distribution in rat brain and the antioxygen convulsions effect of NOSynthase inhibitor

目的：探讨高压氧（ＨＢＯ）作用下大鼠脑纹状体、下丘脑、黑质内氧化氮合酶（ＮＯＳ）阳性细胞分布的变化及其与氧惊厥的关系。方法：ＳＤ大鼠３５只，随机分为３组：常压对照组（ＮＰ组）５只，高压空气对照组（ＨＢＡ组）５只，和ＨＢＯ实验组（ＨＢＯ组）２５只。ＨＢＡ组和ＨＢＯ组动物分别给予０．２５ＭＰａ高压空气或纯氧，升压２０分钟；在０．２５ＭＰａ下ＨＢＡ组稳压７小时，ＨＢＯ组再分为５个小组（每组５只），分别稳压１小时（５只）、４小时（５只）和７小时（３个小组１５只），后者中２个小组各５只分别在进舱前２０分钟予腹腔注射生理盐水或ＮＧ－硝基－Ｌ－精氨酸（ＮＮＬＡ），然后经２０分钟减至常压。动物出舱后立即灌注取脑，利用还原型烟酰胺腺嘌呤二核苷酸磷酸黄递酶（ＮＡＤＰＨ－ｄ）组织化学方法，观察氧化氮合酶（ＮＯＳ）阳性细胞在大鼠脑纹状体、下丘脑、黑质内分布的变化及其与氧惊厥的关系，并用ＮＯＳ抑制剂ＮＮＬＡ观察其抗氧惊厥作用。结果：ＨＢＯ暴露１小时上述脑区ＮＯＳ阳性细胞数与对照组相比无明显变化（Ｐ＞０．０５）；而ＨＢＯ暴露４、７小时与对照组相比，ＮＯＳ阳性细胞数在上述脑区明显增加（Ｐ＜０．０５）；其中７小时组又高于４小时组（Ｐ＜０．?

Aim:To investigate the distributional changes of NOSpositive neurons in substantia nigra(SNR),striatum and hypothalamus of rat brain after different time of hyperbaric oxygen(HBO) exposure and their ralationship with O2 convulsions.Methods:35 SD rats weighing 200￣250 g were randomly divided into 3 groups:the normal pressure(NP) group,5 rats;the hyperbaric air(HBA) group,5 rats;and the hyperbaric oxygen(HBO) group,25 rats.The animals of the HBA and HBO groups were put into the same hyperbaric chamber and were given 025 MPa air or 100% oxygen.The chamber pressure was increased from normal to 025 MPa in 20 min and the HBA group was kept at this pressure for 7 hours;whereby the HBO group was further divided into 5 groups with 5 rats in each group and they were kept at this pressure for 1 hour(5 rats),4 hours(5 rats)and 7 hours(3 groups,15 rats)with each 5 rats in the latter 2 groups given ip NS or NGnitroLarginine(NNLA)20 min before entering the chamber respectively.The time of decompression was 20 min.Then the animals were taken out and perfused and dissected out at once. The NOsynthase(NOS)positive neurons in SNR,striatum and hypothalamus were observed by the method of NADPHdiaphorase histochemistry with relation to oxygen convulsions.At the same time,NOS inhibitor NNLA was used to observe its antioxygen convulsions effect.Results:The number of NOSpositive nearons in SNR,striatam,and hypothalamus in HBO 1 hour group was maintained near control(P>005);while in HBO 4 hours and 7 hours groups the number was increased relative to control(P<005).The number of NOSpositive neurons in HBO 7 hours group was increased relative to HBO 4 hours group(P<005).10 out of 15 rats without NNLA injection in the HBO 7 hours groups produced O 2 convulsions,whereas the remaining 5 rats with NNLA injection together with other groups of rats all had but no signs of convulsions in the experiment. Conclusion:O 2 convulsions is closely related to the increase of NOSpositive neurons in SNR,striatum and hypothalamus of rat brain.NOS inhibitor(NNLA) can significantly protect the rats from HBO mediated convulsions.