动物模型,IBS z-bo 2020-08-07 490

　　(1) Replication method 8-day-old Wistar rats, using an angioplasty (PTCA) balloon (3.0mm×20mm) for colon stimulation (CI), 1 min/time, 2 times/d (interval 30 min), for 1 week The balloon pressure was 4kPa (30mmHg) (weak stimulation pressure), 6kPa (45mmHg) (strong stimulation pressure), and changed to 8kPa (60mmHg) in the second week. The rats in the control group were gently picked up every day and stroked their perineum for 1 min. The PTCA balloon was wiped with 75% ethanol and normal saline before each expansion, and the stool and body weight of the rats were observed. The suckling mice rested for 2 weeks after completing the above stimulation, and the adult rats undergo rectal dilation (CRD) at the 5th, 6th, 7th, and 13th weeks. The colon dilatation balloon is a medical latex glove finger with a length of 4 cm. It is fastened with an endoscopic retrograde cholangiopancreatography (ERCP) catheter with No. 4 surgical thread. The pressure gauge, syringe and ERCP catheter are connected to the three-way tube respectively, and the syringe is drawn in air. Fasting for 12 hours before colonic dilation, inserting the balloon 6-8cm from the anus, and injecting air after the rats adapt to 5 minutes to make the pressure in the balloon reach 2.7, 3.0, 5.3, 6.6, 8.0, 9.3, 10.6kPa, 20 , 30, 40, 50, 60, 70, 80mmHg, each pressure lasts for 20s, repeated 5 times, with a 3min interval between each pressure, and double-blindly record the behavior of the rat's colon under stimulation when each pressure is given The academic scoring is performed 5 times, and the average value is taken. After the experiment, the animals were sacrificed, and the descending colon was removed 10 cm from the anus for histopathological examination. The behavioral score is semi-quantitatively scored according to the rat's abdominal muscle contraction response (AWR) during CRD: ①The rat has no behavioral response when the colon expands: 0 points. ② When the colon expands, the body is still and the head movement decreases: 1 point. ③The abdominal muscles contract when the colon expands, but the abdominal muscles are not lifted off the table: 2 points. ④The abdominal muscles contract and lift off the table when the colon expands: 3 points. ⑤The pelvis is lifted when the colon expands and the body is arched: 4 points. Colonic histopathological examination scoring criteria: ① A small amount of neutrophil infiltration in the lamina propria, mild or no interstitial edema: + (mild). ② Moderate granulocyte infiltration in the lamina propria, moderate interstitial edema: ++ (moderate). ③ Diffuse infiltration of neutrophils in the lamina propria, severe interstitial edema: +++ (severe).

　　(2) Characteristics of the model When rats received different pressure colon mechanical stimulation during the neonatal period, the rectum dilated after adulthood. The abdominal muscle contraction response (AWR) score showed that the noxious stimulation threshold of model rats was significantly decreased, but 4.0kPa (30mmHg) There is no significant difference between the decrease range of weak stimulation pressure and 6.0kPa (45mmHg) strong stimulation pressure. The tolerance threshold of rectal dilatation also indicated that the initial sensory threshold, pain threshold, and maximum tolerance threshold of model rats decreased, and female rats had worse tolerance to CRD. In addition, the results of body weight and pathological biopsy showed that the weight of the model rats was not significantly abnormal, and there was no obvious damage to the tissue structure of the descending colon, but the tissue sections had mild neutrophil infiltration. The interstitium has no obvious edema, which is mild.

　　(3) Comparative medicine. Repeated expansion of the colorectal cavity can cause peripheral and central sensitization, including short-term functional changes in peripheral and central neuronal activity, as well as continuous changes in central nervous system plasticity, so it is sensitive after the stimulation is relieved The persistence exists. This method uses the PTCA balloon to stimulate the colorectal dilatation continuously or repeatedly in the suckling rats, which can lead to increased visceral sensitivity, and this acquired sensitivity can continue to adulthood, which is manifested as the initial sensation of rectal dilatation on CRD The threshold, pain threshold, and maximum tolerance threshold decreased significantly, which is consistent with human IBS symptoms. Although the etiology of this model is different from that of human IBS, it can better simulate the most prominent symptom of IBS abdominal pain, and the stimulation can be quantitative, minimally invasive, easy to control, and reproducible. The animal can stay awake and reliable. Physiological and behavioral responses have become an important method for studying visceral sensory function, and it is currently one of the most widely used animal models.