Establishment of model of visceral pain due to colorectal distension and its behavioral assessment in rats

瞄准：证实内脏的疼痛经由颜色为表面的扩张(CRD ) 建模并且由在老鼠测量腹的屈肌反射(AWR ) 的分数评估 CRD 的行为的回答的效率。方法：称 180-240 g 的 38 只男 SD 老鼠被用来建立内脏的疼痛模型。老鼠与 7 厘米 intra-anally 被插入在醚麻醉下面的长灵活的乳胶汽球，和由与空气使汽球膨胀的表面的扩张在从麻醉恢复以后被成为 30 min 的颜色。五个 AWR 分数(到 AWR4 的 AWR0 ) 被用来估计有害内脏的刺激的紧张。它被认为是最低压(kPa ) 的阀值。因为腹的 flatting 被颜色导致表面的扩张。结果：到下降冒号和直肠的扩张的精力旺盛的 AWR 在 100% 被发现醒着测试的老鼠。越高扩张的压力，越 higher AWR 的分数。0， 2.00， 3.33， 5.33 和 8.00 kPa 的扩张压力生产了不同 AWR 分数(P【0.05 ) 。AWR 的痛觉阈为在起始的终结(第一 1-3 扩张) 以后的多达 80 min 是不变的，吝啬的阀值是 3.69+/-0.35 kPa。吗啡硫酸盐的全身的管理在一个剂量依赖者和 naloxone 提高了内脏的疼痛的阀值可逆举止。结论：在表面的扩张能估计的颜色期间获得 AWR 有害内脏的刺激的紧张。到内脏的痛觉阈清楚、不变、可靠的 CRD 的腹部(AWR 3 ) 的 Flatting。这个疼痛模型和它的行为的评价对关于内脏的疼痛和止痛剂的研究好。

AIM： To establish a visceral pain model via colorectal distension （CRD） and to evaluate the efficiency of behavioral responses of CRD by measuring the score of abdominal withdrawal reflex （AWR） in rats. METHODS： Thirty-eight male SD rats weighing 180-240g were used to establish the visceral pain model. The rat was inserted intra-anally with a 7 cm long flexible latex balloon under ether anesthesia, and colorectal distensions by inflating the balloon with air were made 30 min after recovering from the anesthesia. Five AWR scores （AWR0 to AWR4） were used to assess the intensity of noxious visceral stimuli. It was regarded as the threshold of the minimal pressure （kPa）. For abdominal flatting was induced by colorectal distension. RESULTS： A vigorous AWR to distension of the descending colon and rectum was found in 100% of the awake rats tested. The higher the pressure of distension, the higher the score of AWR. The distension pressures of 0, 2.00, 3.33, 5.33 and 8.00 kPa produced different AWR scores （P〈0.05）. The pain threshold of AWR was constant for up to 80 min after the initial windup （first 1-3 distensions）, the mean threshold was 3.69±0.35 kPa. Systemic administration of morphine sulfate elevated the threshold of visceral pain in a dosedependent and naloxone reversible manner. CONCLUSION： Scoring the AWR during colorectal distensions can assess the intensity of noxious visceral stimulus. Flatting of abdomen （AWR 3） to CRD as the visceral pain threshold is clear, constant and reliable. This pain model and its behavioral assessment are good for research on visceral pain and analgesics.