动物造模,药效评价,自发性动物肿瘤 z-bio 2024-09-23 382

　　A type of tumor that naturally occurs in experimental animal populations without conscious artificial experimental treatment is called spontaneous tumor. The discovery comes from researchers' observation and understanding of animals. The type and incidence rate of spontaneous tumors may vary with the species, strains and types of experimental animals. Mice are the majority of them, and the tumor prone sites of different strains of mice are also different. The incidence rate of spontaneous tumors in rats is far lower than that in mice, especially the incidence rate of digestive system tumors, respiratory system tumors and leukemia. In tumor experimental research, tumor models of experimental animals with high incidence rate should generally be selected as the research object, and tumor models with low incidence rate should be used as the control.

　　Spontaneous tumors mostly occur on the body surface or in the parts that are easy to find in the current physical examination, and most of them are viral. For example, the incidence of breast cancer in C3H mice after birth is high, the incidence of lung cancer in A strain mice within 18 months after birth can reach 90%, and the incidence of leukemia in AKR and C57 mice is high. The study on the growth pattern of AKR leukemia suggests that the mouse was born with carcinogenic RNA virus. Within 6-13 months of age, the mortality rate of spontaneous tumors in mice is 15% -20% per month. Tumor cells with proliferative ability often appear in the thymus of mice one month before diagnosis, and the median survival period after diagnosis is 16 days. The elucidation of these patterns provides basic knowledge for chemotherapy. At present, the most frequently used spontaneous tumor model in new drug research is mouse spontaneous breast cancer. C3H mice with high spontaneous rate or the first generation CD2F1 mice crossed by BALB/c female mice and DBA/2 male mice are commonly used. They can detect tumors about 10 months after birth, and then survive for 20 to 35 days to die. Such mice can be reproduced in large numbers, and the spontaneous tumor can reach 70%. Generally, they are given drugs in groups after the detection of tumor blocks. The efficacy of drugs can be evaluated by observing the extension rate of their average survival time.

　　The advantages of using spontaneous tumor models in tumor experimental research are: firstly, compared with tumors induced by experimental methods, spontaneous tumors are more similar to human tumors, which is conducive to applying animal experimental results to humans; Secondly, the conditions for the occurrence of this type of tumor are relatively natural, and it is possible to identify undiscovered environmental or other carcinogenic factors through careful observation and statistical analysis. The role of genetic factors in tumor occurrence can be emphasized. The disadvantage of using spontaneous tumor models is that the occurrence of tumors may vary greatly, it is impossible to obtain a large amount of oncological materials in a short period of time, observation time may be longer, and experimental costs may be higher.

　　Another use of spontaneous tumors is to establish transplant tumor models, such as the widely used mouse Lewis lung cancer, which was discovered by Lewis in 1951 on untreated C57BL mouse lungs as undifferentiated epithelioid carcinoma. It is the world's first solid transplant tumor model established from spontaneous tumors in mice; For example, Ehrlich ascites carcinoma in mice spontaneously originated from the mammary gland and was later artificially established as ascites tumor; In addition, there are also transplant tumor models established with spontaneous breast cancer in C3H mice, spontaneous leukemia in ARK mice, and spontaneous liver cancer in C3H/He mice