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脊髓蛛网膜下腔注射P 物质引起大鼠结肠炎

林萍, 吴星宇, 潘慧, 蒋惠君, 梅林

北京大学医学部生理学与病理生理学系，北京 100191

摘要

本实验从神经源性炎症的角度探讨结肠炎(colitis)发病的机理，并为神经源性结肠炎的假说提供直接的证据。健康雄性Sprague-Dawley 大鼠(180~220 g)经水合氯醛腹腔麻醉后，将PE-10 管插入脊髓蛛网膜下腔达T12~L5 水平。鞘内(intrathecal, ith)注射P 物质(substance P, SP)，每天一次，共14 天。神经激肽-1 (neurokinin-1, NK1)受体拮抗剂([D-Pro2, D-Trp7, 9] –SP, 22.4 μg)于每次ith 注射SP 前10 min ith 预处理。观察疾病活动指数(disease active index, DAI)、结肠和脊髓组织的大体/ 镜下病理、以及移动抑制因子(migration inhibitory factor, MIF)蛋白的表达。结果显示：ith 注射SP 10 μg 和20 μg 能够引起大鼠DAI 明显升高、结肠组织炎性细胞浸润、腺体萎缩和MIF 高表达(与生理盐水组相比，P<0.05，P<0.01) ；但在脊髓，仅在ith 注射SP 20 μg 组见到轻度充血水肿，并无明显神经元坏死。NK1 受体拮抗剂预处理，能够延长ith 注射SP 20 μg 后DAI 开始升高的潜伏期、减小DAI 升高的幅度、抑制MIF 在结肠组织的高表达。上述实验结果表明，ith 注射SP 能够引起大鼠结肠炎，该效应是通过激活脊髓NK1 受体实现的，肠组织的MIF 参与了此炎症过程。脊髓高浓度SP 能通过NK1 受体介导结肠炎这一发现可能具有潜在的临床意义。

关键词： 结肠炎; 神经源性炎症; 脊髓; P 物质; 神经激肽- 1 受体; 大鼠

分类号：R332；R363；R574.62

Rat colitis induced by intrathecal injection of substance P

LIN Ping, WU Xing-Yu, PAN Hui, JIANG Hui-Jun, MEI Lin

Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing 100191, China

Abstract

The aim of this study was to, from the point of neurogenic inflammation, explore the pathogenesis of colitis and to provide direct evidence for the neurogenic colitis hypothesis. Male Sprague-Dawley rats (180-220 g) anesthetized with chloral hydrate were intrathecally (ith) implanted with polyethylene-10 (PE-10) catheter to reach the spinal cord T12-L5 level. Substance P (SP) was ith injected once a day for 14 d. The disease active index (DAI) score was calculated by rat body weight and stool. The macroscopic and HE staining-microscopic pathologies of colon/spinal tissue were evaluated. By immunofluorescence staining, the protein expression of a pro-inflammatory cytokine, migration inhibitory factor (MIF), in colon tissue was detected and was semi-quantitatively analyzed. The results showed that in the colon tissue, inflammation was dose-dependently aggravated by ith SP 10 μg and 20 μg, whereas in the spinal tissue, only slight edema and congestion were seen in SP 20 μg group. The MIF protein of colon tissue was increased in ith SP 10 μg and 20 μg groups (P<0.05, P<0.01 as compared to normal saline group respectively), but in the spinal tissue, there was no obvious MIF protein expression either in SP groups or in normal saline group. Pretreatment with neurokinin-1 (NK1) receptor antagonist ([D-Pro2, D-Trp7, 9] –SP, 22.4 μg, ith, 10 min before ith SP) prolonged the latency of DAI rising and reduced the DAI amplitude, as well as prevented the high MIF expression induced by ith SP. These results suggest that rat colitis can be induced by direct SP stimulation in lumbar spine via activating central NK1 receptor; and that colonic MIF is possibly one of the inflammatory factors involved in this pathogenesis. These data provide a reasonable support to the hypothesis of colitis being a neurogenic inflammation. In addition, a potential clinical significance for the finding that higher concentration of spinal SP can induce colitis via NK1 receptor is discussed.

Key words: colitis; neurogenic inflammation; spinal cord; substance P; NK1 receptor; rats

收稿日期：2009-02-10　　录用日期：2009-05-20

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引用本文：

林萍, 吴星宇, 潘慧, 蒋惠君, 梅林. 脊髓蛛网膜下腔注射P 物质引起大鼠结肠炎[J]. 生理学报 2009; 61 (4): 331-338.

LIN Ping, WU Xing-Yu, PAN Hui, JIANG Hui-Jun, MEI Lin. Rat colitis induced by intrathecal injection of substance P. Acta Physiol Sin 2009; 61 (4): 331-338 (in Chinese with English abstract).