动物造模,药效评价 z-bio 2024-07-24 425

　　Babesia belongs to the class of moths, also known as pear pulp worms. Its transmission medium is ticks. There are several genera of parasitic moths in warm blooded experimental animals, among which Babesia is the most important. All cases of human Babesiosis discovered so far may have originated from animals. There are several species of Babesia that can infect humans, and the number of cases is very small, indicating that most individuals have resistance to clinical onset. If the virulence of Babesia parasites to humans does not undergo unexpected changes, then it may still be a rare but worthy issue to be taken seriously. Babesia jirovecii is a blood parasitic protozoan that seriously endangers animals such as dogs, foxes, and wolves. It is mainly endemic in some areas of China, such as Henan and Jiangsu. Wang Shengliang et al. conducted clinical observations on experimental infections of Babesia jirovecii in dogs and morphological observations of Babesia jirovecii in canine red blood cells; Dong Junyan et al. conducted artificial infection experiments on Babesia jirovecii in dogs and believed that Babesia jirovecii is pathogenic to both spleen harvesting and non spleen harvesting dogs, but the degree of pathogenicity varies; Zhang Shoufa et al. successfully established experimental animal models of Babesia bovis and Trichophyton using SCID mice based on Tsuji M et al.'s model, as well as the method of replacing canine red blood cells with SCID mice established by Arai S et al., and successfully infected them with Babesia bovis. They conducted a study on the SCID mouse model of Babesia bovis infection and concluded that SCID mice with replaced canine red blood cells are currently the most suitable experimental animal model for Babesia bovis proliferation.

　　(1) Method of replication: Select normal SCID mice aged 5-10 weeks. After anesthesia, the spleen is removed and used for replacing canine red blood cells and artificially infecting Babesia jirovecii after complete healing of the surgical site Dog serum: Aseptic normal dog blood is taken to prepare dog serum, which is stored at -20 ℃ for future use Canine red blood cells: Sterile, normal canine defibrinated blood was taken, centrifuged at PBS 1500r/min for 10 minutes, and washed three times. Add an equal amount of normal dog serum suspension. ④ Replacement of canine red blood cells in SCID mice: Inject 0.5ml/mouse intraperitoneally, once every other day, for 3-4 consecutive injections. ⑤ Infection: Take dog red blood cells washed with PBS and infected with Babesia jirovecii (infection rate of about 10%), add an equal amount of normal dog serum suspension, and inoculate them into the abdominal cavity of SCID mice with replaced dog red blood cells at a dose of 0.5ml/animal. Afterwards, inject normal dog serum dog red blood cell suspension into the abdominal cavity every 2 days.

　　(2) On the fourth day after infection, a small amount of parasites may appear in the peripheral blood; On the 7th to 8th day, there was an increase in the number of proliferating worms; On the 10th to 12th day, the red blood cell infection rate can reach about 12%; Afterwards, the number of parasites in the peripheral blood began to decrease, lasting for 15-18 days, and even 25 days before disappearing. The proliferation mechanism of Babesia jirovecii in SCID mice is similar to that of Babesia canis, and it can exhibit symptoms such as anemia and reduced hemoglobin in clinical practice, which are also similar to the clinical symptoms of Babesia canis.

　　(3) The morphology of the proliferating worms in SCID mice treated with medical replacement of canine red blood cells can undergo significant changes, with worms significantly larger than those parasitized in dogs. 2, 4, 8, 16, and 32 worms can often be seen in one red blood cell, and the proportion of these proliferating worms is significantly higher than in dogs. The Babesia jirovecii parasites that grow and proliferate in the peripheral blood of SCID mice parasitize in the red blood cells of dogs that have been replaced. After undergoing morphological changes, Babesia jirovecii returns to dogs, and its body shape and size can be restored to their original state, while still maintaining strong infectivity to dogs. This model animal can be used for the study of the biological characteristics such as morphology, physiology, biochemistry, and proliferation of Babesia jirovecii, as well as for research on pathogenic mechanisms and screening of therapeutic drugs.