低氧对大鼠免疫功能的影响及其神经内分泌调控

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	低氧对大鼠免疫功能的影响及其神经内分泌调控
	白海波
学位类型	博士
导师	杜继曾
	1997
学位授予单位	中国科学院西北高原生物研究所
学位授予地点	中国科学院西北高原生物研究所
学位专业	动物学
关键词	鼠兔大鼠神经内分泌动物生理学
摘要	神经内分泌系统和免疫系统是机体维持自身稳定的重要调节系统，二者以不同的方式，从不同的侧面发挥其生理调节作用。进年来的研究表明神经内分泌－免疫系统间存在一个完整的调节环路，神经内分泌系统不仅可直接影响免疫系统功能，还可通过释放一系列神经肽、神经递质和激素如CRF、阿片肽、ACh、NE、皮质酮等影响免疫系统。应激原作用于机体，将引起应激反应，这是机体受到强烈刺激后民生的、以交感肾上腺髓质及垂体－肾上腺皮质的功能增强为主要特征的非特异性适应反应，是一种多激素参加的全身反应。由于应激时神经内分泌系统的变化，免疫系统也将因此而改变。低氧作为一种特殊的应激原也严重影响着机体的神经内分泌系统，有关低氧对呼吸系统和心血管系统的研究有大量文献报道，至今，有关低氧对免疫系统的影响及神经内分泌调节几无报道。本文以模拟高原低氧的方法比较系统地探讨了低氧对大鼠和高原鼠兔免疫功能的作用，研究了神经肽 CRF、AVP、β-endorphin 及神经递质 NE、ACh 等参与低氧应激大鼠免疫功能的调节机制，结果如下：一、低氧下 HPA 轴应激系统的变化5km 和 7km 急性低氧暴露 24h ，大鼠全血 CRF 水平，血浆 NE 和皮质酮水平随海拔升高而升高，使用 6-OHDA 损毁中枢儿茶酚胺能神经元后，低氧对血浆皮质酮的刺激作用被部分抑制。高原鼠兔经受如上的低氧暴露，未表现出同大鼠类似的神经内分泌变化。二、低氧对大鼠体液免疫的作用大鼠经 5km 和 7km 低氧 10d，溶血素形成随海拔升高受到不同程度抑制；大鼠经再次免疫后以低氧 10d，溶血素形成仍受到抑制；高原土著动物高原鼠兔（Qchotona curzoniae）则不表现上述的抑制现象；若大鼠经 SRBC 腹腔致敏两天后低氧 5d 和 8d，未表现低氧抑制溶血素形成的作用；大鼠侧脑室给予外源性 CRF(1 μg /rat)，可抑制溶血素形成和 IgG 产生；7km 低氧大鼠侧脑室给予 CRF 受体阻断剂（α-helicalCRF(9-41)）50 μg 对低氧抑制溶血素形成有一定的阻断作用，可部分阻断低氧抑制 IgG 产生；大鼠腔注射1 μg CRF 对溶血素形成和 IgG 产生无影响；与假手术组比，大鼠在摘除双侧肾上腺后，低氧对溶血素形成仍然抑制。三、低氧下自主神经系统对大鼠免疫的调节作用大鼠 5km 低氧暴露 24h，脾淋巴细胞对丝裂原反应性下降，外周交感神经损毁后则可阻断低氧对此的抑制作用；大鼠 5km 和 7km 低氧 48h，肾上腺皮质酮水平随海拔升高而增高，损毁外周交感神经后，5km 低氧升高肾上腺皮质酮水平的作用被阻断；体外培养的大鼠脾淋巴细胞加入不同浓度的乙酰胆碱，胸腺嘧啶核苷掺入作用呈浓度依赖性增加；大鼠 5km 低氧 24h，血浆中乙酰胆碱水平下降。四、急性低氧下去甲肾上腺素对大鼠淋巴细胞转化的调节作用与对照相比，7km 急性低氧 24h 淋巴细胞转化下降；5km 低氧暴露时间为 7d、20d时，低氧抑制淋巴细胞转化；侧脑室注入 5nM NE，淋巴细胞转化也下降； 7km 10h 低氧暴露时，侧脑室注入酚妥拉明（phentolamin） 25 μg/rat 则使低氧抑制淋巴细胞转化得到部分反转；5nM NE，血液 CRF 水平升高，脑室注入酚妥拉明后则降低；7km 24h 低氧，下丘脑儿茶酚胺水平升高，血液 CRF 水平也升高；7km 10h 低氧暴露的脾淋巴细胞加入不同浓度的 CRF 体外培养，呈现出浓度依赖性淋巴细胞转化下降现象。五、低氧对新生大鼠细胞免疫的影响5km 海拔高度低氧暴露 24h 不抑制新生大鼠脾单个核细胞 DNA 含量及脾淋巴细胞转化，而暴露5天时则抑制 DNA 含量及脾淋巴细胞转化；7km 海拔高度低氧暴露 24h，DNA 含量及脾淋巴细胞转化均受抑制；测定脾脏中乙酰胆碱及儿茶酚胺含量显示 7km 海拔 24h 低氧导致乙酰胆碱下降，儿茶酚胺升高；用 DSP-4 中枢药理性损毁 NE 神经元，可使 7km 海拔低氧 24h 抑制的脾淋细胞 DNA 含量有一定的恢复，此时脾脏中儿茶酚胺含量下降。六、促肾上腺皮质激素释放激素及去甲肾上腺素对高原鼠兔体液免疫的抑制作用高原鼠兔第三脑室注入 CRF 1 μg 可报制免疫抗体生成，而在第三脑室注入 CRF 受体阻断剂 α-helical CRF(9-41)50 μg 后再注入 CRF 1 μg 则可取消 CRF 对抗体生成的抑制作用；第三脑室注入 5nM NE ，与对照相比，抗体水平下降，而使用 6-OHDA 损毁脑内交感神经系统则使抗体水平升高；脑室注入 CRF 和 NE 血清皮质酮水平分别升高，脑室预注入 6-OHDA 后血清皮质酮水平下降。七、低氧下 β-内啡肽对大鼠免疫功能的影响正常大鼠脑室注射 β-EP （lng/rat）溶血素生成和 IgG 产生受到明显抑制，脾脏单个核细胞 DNA 含量也下降；7km 48h 低氧同样使溶血素的产生明显下降，大鼠脑室注射阿片受体阻断剂纳屈酮可使低氧造成的 IgG 和溶血素生成抑制翻转，低氧抑制的脾脏单个核细胞 DNA 合成得到部分阻断；脑室注射 β-EP 与 7km 低氧 12h－样使脾脏中儿茶酚胺含量增加。八、精氨酸加压素对大鼠免疫的调节作用侧脑室注射 100ng VP ，用 ELISA 方法检测的血中对鸡卵白蛋白抗原产生的 IgG 抗体水平比对照升高，而 AVP 的 V_1 受体阻断剂 DPAVP（1-deamino-penicillamine2-O-methyltyrosine-AVP）则可阻断此作用；侧脑室注射 800ng AVP，大鼠对 SRBC 的溶血素水平比对照升高；注射 100ng、800ng AVP 2h 后，脾淋巴细胞对 MTT 产生的颜色反应均比对照增加，而 DPAVP 可阻断之；注射 800ng AVP 后血清 NE 水平比对照明显下降。综上述结果可结论为：1．低氧应激作用于大鼠，其下丘脑-垂体-肾上腺皮质系统和交感神经-儿茶酚胺系统被激活，高原鼠兔因已完全适应低氧环境，故中度低氧不再作为一种应激因子。2．低氧对初次和再次体液免疫均产生抑制作用，而且抑制作用发生在体液免疫的起始阶段，其抑制作用与中枢 CRF 升高有关。3．自主神经系统参与低氧下的免疫调节，交感神经系统有免疫抑制作用，副交感神经起免疫增强作用。4．低氧可抑制淋巴细胞转化，NE 参与急性低氧下对大鼠细胞免疫功能的神经内分泌调节，其调节作用与 NE 激动 CRF 而且是通过 α 受体起作用有关。5．低氧可抑制新生大鼠的细胞免疫，这种抑制作用可能与交感神经兴奋下丘脑 CRF 激活及副交感神经抑制有关。6．高原鼠兔中枢 CRF 和 NE 水平升高可对体液免疫产生抑制作用，其作用机理系 NE 激活 CRF，CRF 进而激活 HPA 轴起作用。7．阿片类物质在急性氧应激过程中参与了对大鼠免疫功能的调节作用。其对低氧免疫功能的抑制作用可能与激活交感神经系统有关。8．下丘脑 AVP 通过 V_1 受体增强大鼠免疫功能，其机制可能与下丘脑 AVP 抑制该处 CRF 释放进而减弱 HPA 轴对免疫的抑制。
其他摘要	Nervous and immune systems are the important defensive and regulatory systems for keeping internal environment homeostasis of the body. A growing body of evidence has greatly enhanced our understanding of the interrelationship between the immune system and the neuroendocrine system. More recently experimental data have demonstrated that hormones and neuropoeptides released during stress could modulate immune responses. Nevertheless, the references concerning the effect of hypoxia on immune function and regulation by neuroendocrine are quite few. This paper, using simulated altitude in hypobaric cabin, has systematically for the first time investigated the effects of hypoxia on the immune function and the mechanisms involved in the immune response to hypoxia stress in the rat and plateau native mammal animal (Ochotona Curzoniae, Pika), the results and conclusions summarized are as follows:1.HPA response to acute hypoxia. The present study was desingened to examine the effects of hypoxia on neuroendocrine system of rats and Plateau native mammals (Ochotona curzoniae). Rats were exposed to 5km and 7km of altitude for 24 h, CRF contents in whole blood, NE and corticosterone levels in plasma increased with enhancement of altitude; The increased cortiosterone level was partly reversed when central sympathetic nervous system was destroyed by 6-OHDA; Hypoxia showed no noticeable role in Ochotona curzoniae. These results suggest that acute hypoxia activates HPA axis perhaps also sympathtic nervous system in rats, but not in Ochotona curzoniae as the pika well-adapted genetically to hypoxia environment.2.Inhibition effect of hypoxia on humoral immunity of rats To study the effect of hypoxia on humoral immunity function of rat and pika, the specific antibody production to novel antigen (IgG) and immunoresponse to sheep red blood cell (hemolysin forming) were measured. The results show Hypoxia at altitude of 5km and 7km for 10d resulted respectively in decrement in hemolysin forming in rats, as compared with the control group kept at 2.3 km. When the rats were secondarily immunized and kept at the same hypoxia for 10d, both altitude of hypoxia still produced the reduction in hemolysin formation. However this was not found in the pikas. When the rats were immunized two days before hypoxia, 5km hypoxia for 5d and 8d failed to suppress hemolysin formation Intracerebroventricular (icv) injection of CRF(1.0 μg/rat) decreased hemolysin formation and the production of IgG respectively, but intraperitoneal (ip) injection of CRF (1.0 μg/rat) had no effect. However, icv injection of CRF receptor antagonist (α-helical CRF(9-41), 50 μg/rat) prior to 7km hypoxia abolished partly the hypoxia-induced suppression of IgG production. Adrenalectomy in rats lowered hemolysin formation. The above results demonstrated that hypoxia suppresses humoral immunity function and alters initial antigen processing probably through a mechanism of increase of CRF in CNS.3.The autonomic nervous system involved in regulation of immune function in rats during hypoxia When rats were exposed to 5km altitude for 24h, which inhibited spleen T lymphocyte proliferation induced by concanavalin (Con A), but the action was abolished through peripheral sympathetic-destroyed; When rats were subjected to 5km and 7km altitude for 48h, the adrenal corticosterone contents increased in a parallel with the increase of altitude in rats but they received peripheral sympathectomy using 6-OHDA, the increased adrenal corticosterone action was blocked; T cells were in vitro incubated simultaneously with ACh showing a concentration dependent enhancement of T cell proliferation; The plasma levels of ACh were decreased after rats were exposed to 5km for 24h. Taken with these results, conclude that autonomic nervous system involved in the regulation of immune function in rats during hypoxia.4.Norephinephrine regulation of T-lymphocyte proliferation of rat during acute hypoxia In the present study, the role of NE in the immunoregulation in rats during simulated hypoxia in a hypobaric cabin was examined. It was found that 7km for 24h of hypoxia inhibited T-lymphocyte proliferation; For 7d and 20d of hypoxia at 5km altitude, T-lymphocyte proliferation still present a reduce respectively; Intracerebroventricular (icv) injection of 5 * 10~(-6) mol/L NE decreased T-lymphocyte proliferation; ICV injection of phentolamine prior to 7km for 10h hypoxia attenuated hypoxia-induced suppression of T-lymphocyte proliferation; In addition, 7km 10h hypoxia increased CRF levels in blood and catecholamines in hypothalamus; An increased circulation CRF level was also noted after injection (icv) of 5 * 10~(-6) mol/L of NE. Hypoxia corresponding 7km altitude for 10h stimulates spleen-lymphocytes incubated with CRF, but T-lymphocyte proliferation decreased with increasing CRF concentration. These findings suggest that hypoxia inhibits T-lymphocyte proliferation probably through an immune inhibitory action by CRF and by NE through CRF. 5. The effect of hypoxia on cellular immune function of neonatal rats The effect of hypoxia on the immune function of neonatal rats in age of 14 days as well as on the levels of ACh, catecholamine in spleen were studied. When the animals were exposed to 5km simulated altitude in a hypobaric cabin for 5 d resulted in a decrement in DNA contents in spleen lymphocytes and a decrease in lymphocyte proliferation; Similar suppression of these two parameters of immune function in exposed to 7km for 24h was noted; The suppressive effects of 7km 24h hypoxia on DNA contens were partly blocked when rats were pretreated icv with DSP-4 one day before hypoxia; The levels of catecholamine in spleen were incresed, meanwhile the levels of ACh were decresed after 7km exposure for 24h. These observations indicate that hypoxia suppress cellular function of neonatal rats and its mechanisms may be through activation of sympathetic nervous system, CRF release in hypothalamus and a restraint of parasymphathetic one.6.The inhibitory effect of corticotropin releasing factor and norepinephrine on humoral immune function of Ochotona Curzoniae What action the CRF and NE played in modulating immune function in the brain of Ochotona curzoniae was studied. The changes of humoral immune function of Ochotona curzoniae were examined by icv injection of CRF, NE and their blocker. The results showed that icv CRF (1.0μg) resulted in a decrement in the production of IgG; Central administration (icv) of the CRF antagonist -helical CRF-(9-41) 50μg completely blocked the immunosuppressive action of CRF, when animals were icv injection of NE 5nM produced a significant suppression of the IgG production. After destroyed central sympathetic nervous system with 6-OHDA, the IgG levels increased; These findings suggest that enhanced CRF level in the brain might be a source to reduce humoral immune function by activating HPA and NE action need through CRF in the Ochotona curzoniae.7.The effect of β-endorphin in the regulation of immune function of rats during acute hypoxia In order to investigate the role of β-endorphin in the regulation of immune function of rats during acute hypoxia, the effects of β-endorphin on mitogeninduced spleen lymphocyte DNA synthesis and hemolysin formation as well as IgG production were observed. It was found that after rats received icv injection of β-endorphin (1 ng/rat), the T-lymphocyte DNA content, the hemolysin-forming capacity of SRBC-sensitized rats and IgG level were reduced significantly compared with control group (icv normal saline); Similar suppressive effects on immune function could be found after rats exposed to 7km of altitude in the hypobaric chamber for 48h; Pretreatment with icv injection of naltrexone, the immunosuppressive effects of acute hypoxia were partly blocked; The icv administration of β-endorphin produced an increases in splenic cathcholamines, similar to those of 7km 12h hypoxia treated group. All the findings above suggest that β-endorphin may modulate the immune response to hypoxia stress by opioid receptor and its inhibitory action may be though activating sympathetic nervous system.8.The effects of AVP on immune function of rats The effects of AVP on immune function of rats were studied by using icv. The hymolysin to SRBC and IgG production enhanced with icv 100, 800 ng AVP; Both the enhanced actions were partly blocked by icv preinjection of the V_1 recptor antagonist DPAVP, the resultes suggest AVP bring up immunofunctions through V_1 receptors in PVN of the brain, which inhibits CRF release or through an inhibition on sympathetic nervous system.
页数	92
语种	中文
文献类型	学位论文
条目标识符	http://210.75.249.4/handle/363003/3366
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	白海波. 低氧对大鼠免疫功能的影响及其神经内分泌调控[D]. 中国科学院西北高原生物研究所. 中国科学院西北高原生物研究所,1997.

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