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目的探讨新生期伤害性结直肠扩张刺激(CRD)对发育期大鼠内脏痛觉敏感性的影响。方法8日龄新生SD大鼠随机分成实验组和对照组,每组16只;实验组新生鼠在出生第8天开始给予结直肠刺激,1次/d,连续7d;对照组则不给予结直肠刺激。随后,两组大鼠常规饲养到6周龄时进行内脏敏感性测定。采用腹壁撤退反射(AWR)评分和痛阈测定作为不同的扩张压力下结直肠疼痛反应指标,评估肠道痛觉敏感性。采用单因素和重复测量方差分析进行统计学分析,α=0.05为显著性检验标准。结果6周时两组大鼠体重差异无统计学意义;两组大鼠降结肠均未见明显病理组织损伤;随CRD压力增加,两组幼鼠AWR评分增加,实验组幼鼠CRD在60mmHg和80mmHg之间评分差异无统计学意义;在20、40、60mmHg范围内,相同压力下,实验组幼鼠评分明显高于对照组,差异有统计学意义,当CRD压力为80mmHg时,两组评分差异无统计学意义;实验组和对照组大鼠痛阈值分别为26.5±4.9mmHg、47.8±5.0mmHg,两组痛阈差异有统计学意义(F=149.753,P<0.01)。结论新生期进行持续的结直肠刺激的确能造成大鼠痛阈下降,出现慢性内脏高敏感性,并且这种高敏感性能持续到幼年期,同时无明显的组织学改变。
Objective To investigate the effect of neonatal noxious colorectal distension stimulation (CRD) on visceral hyperalgesia in developing rats. Methods 8-day-old newborn SD rats were randomly divided into experimental group and control group, with 16 rats in each group. The neonatal rats in the experimental group were given colonic stimulation once a day for 7 days and the control group received no stimulation Rectal stimulation. Subsequently, both groups of rats were routinely housed and tested for visceral sensitivity at 6 weeks of age. Abdominal wall reflex (AWR) score and pain threshold were used as indicators of colorectal pain response under various dilatation pressures to assess intestinal nociceptiveness. Single factor and repeated measures analysis of variance were used for statistical analysis, α = 0.05 for the significance test. Results There was no significant difference in body weight between the two groups at 6 weeks. No significant pathological changes were observed in the ascending colon of rats in both groups. The AWR score of the two groups increased with the increase of CRD pressure. 80mmHg score was no significant difference; 20,40,60 mmHg range, the same pressure, the experimental group of young rats score was significantly higher than the control group, the difference was statistically significant, when the CRD pressure of 80mmHg, the two groups of scores There was no significant difference between the two groups. The pain threshold of the experimental group and the control group were 26.5 ± 4.9mmHg and 47.8 ± 5.0mmHg, respectively. There was significant difference between the two groups (F = 149.753, P <0.01). CONCLUSIONS: Continuous colorectal stimulation in the neonatal period can indeed cause a decrease in pain threshold and chronic visceral hypersensitivity in rats, and this high sensitivity continues to infancy with no significant histological changes.