【作者】 卓玲；

【导师】 吴斌；

【作者基本信息】 福建医科大学 ， 儿科学， 2008， 硕士

【摘要】 目的:采用行为学和电生理学评价方法,探讨新生期母婴分离(MS)对幼鼠内脏痛觉敏感性影响;比较内脏高敏感性幼鼠和对照组幼鼠腰骶段脊髓背角Fos蛋白表达,探讨脊髓背角Fos蛋白异常表达在幼鼠内脏痛觉高敏形成中作用。方法:[1]20只SD新生大鼠随机分成MS组和对照组,每组10只;MS组新生大鼠予出生后第2～14天每天与母鼠分离3小时(8:00-11:00am),连续13天,对照组不予任何处理,与母鼠同笼。常规饲养到幼鼠期(6周龄),通过观察大鼠在不同压力结直肠扩张(CRD)刺激后的腹壁撤退反射(AWR)评分、内脏痛阈和腹外斜肌(EOMA)放电测量进行内脏痛觉敏感性评价,选取降结肠进行病理学检查。[2]32只SD新生大鼠按析因设计分成4组,每组8只,A组为MS组,6周龄未给予CRD, B组为MS组并在6周龄时接受CRD,C组为对照组并在6周龄接受CRD,D组为对照组,6周龄未给予CRD。B、C组幼鼠接受CRD刺激后2小时和A、D组幼鼠留取L6至S2脊髓,应用免疫组织化学染色及计算机图像分析系统进行脊髓Fos蛋白免疫阳性(FLI)细胞数和灰度积分值半定量分析。采用SPSS11.0软件包进行统计分析,α=0.05为显著性检验标准。结果:[1]随CRD增加,幼鼠AWR评分增加;AWR评分受新生期接受MS及性别影响(F值分别为26.53、9.24,p<0.001),雌性幼鼠AWR评分明显高于雄性,MS组明显高于对照组,性别与MS之间无明显交互作用;MS组与对照组AWR评分在CRD20mmHg、40mmHg、60mmHg时差异明显,CRD80mmHg时无显著差异。MS组和对照组幼鼠痛阈值(?x±s )为17.67±8.2mmHg、33.83±4.3mmHg(F=30.415,p<0.01)。[2]随CRD增加,幼鼠腹外斜肌放电波幅增加;腹外斜肌放电波幅受MS及性别影响(F值分别为18.83、7.62,p<0.05);雌性幼鼠腹外斜肌放电波幅明显高于雄性,MS组明显高于对照组,MS组与对照组腹外斜肌放电幅值在CRD15mmHg、30mmHg、45mmHg时有明显差异,CRD60mmHg、75mmHg时无显著差异。两组幼鼠降结肠未见明显病理组织损伤。[3]新生期MS和幼鼠6周龄时CRD均可使幼鼠腰骶段脊髓背角FLI细胞数显著升高,FLI细胞灰度积分值显著降低,差别均有统计学意义;MS和CRD对脊髓背角FLI细胞数及灰度积分值影响无交互作用。结论:新生期持续MS可导致幼鼠脊髓初级中枢敏化,接受伤害性CRD刺激后能显著引起脊髓神经元Fos蛋白高表达,造成大鼠痛阈下降,出现慢性内脏痛觉高敏感性,并且这种高敏感性能持续到幼年期,同时没有明显的组织病理学改变。更多还原

【Abstract】 Objective: To explore the effect of maternal separation (MS) stimulation in neonatal period on visceral sensitivity of pain in developing rats by the method of behavior and electrophysiology research. Compareing Fos expression at dorsalhorn of lumbarsacral spinal cord of visceral hypersensibility in developing rats with control rats, in order to investigate the role of Fos abnormal expression in dorsal horn of spinal cord of visceral hyperalgesia in developing rats.Method: [1]20 SD neonatal rats were divided randomly into MS group (n=10) and control group (n=10). Rats in MS group were separated from the dam for 3h/d (8:00-11:00am) on postnatal days 2～14 for 13 consecutive days, rats in control group were not treated and remained in the home cage with the dam. Conventionally breeding to the young period (6-week age), observing the score of abdominal withdrawal reflex (AWR)、visceral pain threshold and measurement of electrical discharge of external oblique muscle of abdomen (EOMA) under different pressures of colorectal distension (CRD) irritation to evaluate visceral algesthesia in rats. Select descending colon to do patholigical examination. [2]According to the factorial design, 32 SD rats were divided into four groups with each 8, Group A was MS group and not imposed on CRD at 6-week age, yet Group B was imposed on CRD as MS group. Group C was imposed on CRD at 6-week age while Group D without treatment both as control group. On the 6th week, after the rats of Group B and C were imposed on CRD for 2 hours while rats of Group A and D not imposed on CRD were sampled the spinal cord from L6 to S2, the semi-quantity analysis of staining density and the cell numbers of Fos-Like Immunoreactivity (FLI) of spinal cord were made through immunohisrochemical coloration and computer image analyzing system. SPSS 11.0 software for Windows was used in all statistical tests.α=0.05 was considered significant.Result: [1]The AWR scores increased gradually with the rising of the CRD pressure in developing rats; neonatal MS and gender had effect on the AWR scores (F was 26.53、9.24 respectively, p<0.001), The AWR scores were obviously higher in female than male rats, and the AWR scores were obviously higher in MS than control rats, there was no interaction between MS and gender on affecting the AWR scores (F =0.97, p=0.339); When the CRD pressures were20mmHg、40mmHg、60mmHg, the AWR scores were higher in MS than control rats signigficantly. But when pressure reached 80 mmHg, there was no significant difference of the AWR scores between two gruops. The Pain Thresholds of MS and control rats(?x±s ) were 17.67±8.2mmHg、33.83±4.3mmHg respectively (F=30.415, p<0.01). [2] With the CRD pressure increased, The amplitudes of spike of EOMA increased too; neonatal MS and gender had effect on the spikes of EOMA (F was 18.83、7.62 respectively, p<0.05 ), the spikes of EOMA were obviously higher in female than male rats, and the spikes of EOMA were higher in MS than control rats, When the CRD pressures were 15mmHg、30mmHg and 45mmHg, the spikes of EOMA were higher in MS than control rats signigficantly. But when pressures were 60mmHg、75mmHg, the differences were no statistical significance. There were no significant differences of weight between two groups and there were no obvious histopatholigical changes in descending colon in MS and control rats. [3]Rats accepted MS in neonatal period and CRD at 6-week age both could make the number of FLI increase and staining density of FLI decrease significantly in lumbosacral spinal dorsal horn, the differences had statistical significance. There was not interaction between MS and CRD on affecting the number and staining density of FLI.Conclusion: The persistent MS in neonatal phase can cause primary central sensitization of spinal cord in developing rats. Accepting detrimental CRD can significantly cause the high expression of Fos in spinal cord and result in decreasing of pain threshold in rats, emerging chronic visceral hyperalgesia. This hyperalgesia can continue to juvenile stage and there is no histological change found in colorectal tissues.更多还原