动物造模 z-bio 2023-10-31 1019

　　Colonic pocket ciliates are found around the world, and human infections are generally sporadic. It is common in experimental primates and can also be found in rats, hamsters, dogs, and pigs. There are reports of AIDS patients complicated with colonic pouch ciliasis. Yang Yue conducted experimental research on the infection of colonic pocket ciliates in pigs and macaques, and found that when human immunity is low, infection with colonic pocket ciliates has pathogenicity; Qu Lizhi et al. used immunosuppressive methods to study the induction of colonic small pouch ciliasis in rats, and believed that there is a direct connection between the onset of infection with ciliates in rats and the immune function of the body.

　　(1) The replication method ① uses the direct smear method to conduct a census of ciliates in rats, and adds 1.5mg/L dexamethasone, 1g/L tetracycline, and 50g/L white sugar to the drinking water of rats with colonic pocket ciliates, allowing them to drink freely. When severe diarrhea occurs in rats and a large number of ciliates are found in the feces, the rats are dissected, the contents of the colon and rectum are taken, and an appropriate amount of physiological saline is added. Double layer gauze is used to filter and count Take 200-220g SD rats and add 1.5mg/L dexamethasone, 1g/L tetracycline, and 50g/L white sugar to their drinking water for 2 consecutive weeks, allowing them to drink freely. After 2 weeks, each rat was gavaged 2 times × The cyst or trophozoite of 1000 colonic pouch ciliates. ③ Direct smear method can be used to check for infection and intensity every 3 days.

　　(2) Model characteristics: After 2 weeks of gavage, rats may experience diarrhea and mucus; After 3 weeks of gavage, diarrhea may worsen, anus may become sticky, body may be thin and hair may be burnt, and death may occur; After discontinuing dexamethasone administration in the fourth week, there is still a possibility of death; In the 5th week, the symptoms of diarrhea were alleviated, feces formed, and there was still mucus in the stool; After the 8th week, it returned to normal, and it is still possible to find trophozoites in the feces of rats until the 11th week. The clinical manifestations of infected rats are similar to those of acute human patients, and the infected rats show a worm carrying state after returning to normal, which is also similar to the asymptomatic worm carrying phenomenon in some people. Trophosomes can cause intestinal tissue ulcers in humans and can also cause ulcerative lesions in the intestines of rats. Compared with using pigs or monkeys to create models of colonic pocket ciliasis, using rats has the advantages of convenient operation, low cost, and easy feeding and management.

　　(3) Comparative medical rats have strong resistance to colonic pocket ciliates. Immunosuppressive methods are used to induce the onset of disease in rats. Due to individual differences in rats, some of them may die during the onset of disease. Therefore, appropriate consideration should be given to the number of rats used for modeling. The histopathological changes of intestinal ulcers in this model animal are similar to those caused by human Entamoeba histolyticus infection, and the clinical manifestations of the disease are also similar to those of amoebic dysentery. The distinction can be made by examining the cysts or trophozoites of ciliates and Entamoeba histolytica in the colon. This model can be used for studying its pathogenicity and other aspects.