Mice and guinea pigs are the most commonly used animal models in biomedical research. When selecting an animal model, we need to consider various factors such as the purpose of the research, the characteristics of the research field, and the experimental conditions. Only by choosing the right animal model can we better simulate human disease processes and improve the reliability of experimental results, thus providing strong support for biomedical research. This article will introduce the characteristics, advantages and disadvantages, and main uses of various types of mice and guinea pigs.

1. Mice

1. BALB/c Mice

In 1913, Bagg purchased the albino mouse original species from the American businessman O'Shell (Ohio) and bred it in a group. MacDowell began to breed inbred strains in 1923, and by 1932 it had reached 26 generations and was named the BALB/c strain. Andervont and others made BALB/c widely disseminated and applied. In 1985, our country introduced BALB/c from the NIH of the United States to the Institute of Experimental Animals of the Chinese Academy of Medical Sciences, the 180th generation.

Coat color: albino.

Main features:

① The natural occurrence rate of mammary gland tumors is low, but the incidence rate is high when induced by mammary gland tumor virus; tumors of the ovary, adrenal gland and lung have a certain risk in this mouse incidence rate. ② Susceptible to chronic pneumonia. ③ Very sensitive to radiation. ④ Compared with other inbred strains, the ratio of liver, spleen and body weight is larger. A 20-month-old male mouse had amyloidosis in the spleen. ⑤ Spontaneous hypertension, heart disease in old rats, and arteriosclerosis in both male and female rats. ⑥ Complement-sensitive to Salmonella typhimurium and moderately sensitive to measles virus. Sensitivity to Leishmania spp., Rickettsia spp., and histamine susceptibility factors of pertussis.

Main uses: Widely used in oncology, physiology, immunology, nuclear medicine research, and the preparation of monoclonal antibodies.

2. C57BL mice

In 1921, Little used the mouse strain of Abby Lathrop, female mouse No. 57 and male mouse C57BL was obtained by mating No. 52. In 1937, two sublines, C57BL/6 and C57BL/10, were isolated from C57BL. In 1985, he was transferred from Olac to the Institute of Experimental Animal Research, Chinese Academy of Medical Sciences.

Coat color: black.

Main features:

① The natural occurrence rate of breast tumors is low, and it is difficult for chemicals to induce breast and ovarian tumors. ②12% had eye defects; 16.8% of female mice and 3% of male mice had microphthalmia or no eyes. Cortisone can induce cleft palate, with an incidence rate of 20%. ③ Moderate tolerance to radioactive substances; high complement activity; easier to induce immune tolerance. ④ Sensitive to Mycobacterium tuberculosis. There is some resistance to mousepox virus. ⑤Higher interferon production. ⑥ High alcohol addiction and low concentration of epinephrine lipids. Sensitivity to pertussis histamine susceptibility factor. ⑦ Often regarded as the "standard" inbred strain, it provides the genetic background for many mutant genes.

Main uses: It is a commonly used strain in oncology, physiology, immunology, and genetics research.

3. BALB/c-nu nude mice

In 1973, C.W. Friis of Denmark discovered spontaneously mutated hairless mice in the BALB/cA inbred mouse strain. The mutated mice had hypoplastic thymus and missing immune T cells, and were bred into BALB/cA-nu.

Main characteristics:

① Hairless, naked, and without thymus. With age, the skin gradually becomes thinner, wrinkles appear on the skin of the head and neck, and growth and development are retarded. ② Due to the absence of thymus and only thymus remnants or abnormal thymic epithelium (the epithelium cannot differentiate T cells normally), there is a lack of mature T lymphocytes, resulting in low cellular immune function. However, the NK cell activity of 6- to 8-week-old nude mice was higher than that of ordinary mice. ③B lymphocytes are normal, but their immune function is poor. The immunoglobulins secreted by B lymphocytes are mainly IgM and contain only a small amount of IgG. ④ Poor resistance, prone to viral hepatitis and pneumonia. Therefore must be kept in a barrier system. ⑤ In order to improve the reproduction rate and survival rate, the breeding method of mating homozygous male mice with heterozygous female mice is generally used to obtain 1/2 homozygous offspring. ⑥Commonly used nude mouse strains: BALB/c-nu, NIH-nu, NC-nu Swiss-nu, 03H-nu, C57BL-nu, etc.

Main uses: Widely used in research on basic medicine and clinical medicine such as oncology, immunology, and toxicology.

4. SCID mice

SCID (severe combined immune deficency, SCID) means severe combined immune deficiency in English, and SCID mice are severe combined immune deficient mice. It was first discovered in 1983 by Bosma M.J in the United States from the C·B-17 inbred strain of mice that it was caused by a mutation in a single recessive gene located on chromosome 16, also known as scid. , SCID mice are a homologous inbred strain of C·B-17/lcrJ. It was introduced to my country from Jackson Laboratory in the United States in 1988.

Main features:

① The appearance of SCID mice is the same as that of ordinary mice, and their weight and development are normal. Only the weight of the thymus, spleen, and lymph nodes is only less than 1/3 of the weight of normal mice. ② T lymphocytes and B lymphocytes in the thymus, spleen, and lymph nodes are greatly reduced, and cellular immunity and humoral immune function are defective; but the functions of macrophages and NK cells are not affected. ③The bone marrow structure is normal, and the white blood cells and lymphocytes in the peripheral blood are reduced. ④Easily die from infectious diseases and must be kept in a barrier system. ⑤Both sexes are fertile, with 3 to 5 litters per litter, and a lifespan of more than 1 year.

Main uses: widely used in research on immune cell differentiation and function, reconstruction of xenogeneic immune function, preparation of monoclonal antibodies, research on human autoimmune diseases and immunodeficiency diseases, virology and oncology research wait.

2. Rats

1. Wistar rats

Bred by the Wistar Research Institute in the United States in 1907, they are now found in countries around the world 's laboratory. Introduced from Japan and the former Soviet Union, it is one of the earliest, most widely used, and largest rat strains introduced in my country.

Coat color: albino.

Main characteristics:

① The head is wider, the ears are longer, and the length of the tail is shorter than the body length. ② The sexual cycle is stable, the fecundity is strong, and the number of litters is large. The average number of litters per litter is about 10, and the growth and development are fast. At 10 weeks of age, the weight of male mice can reach 280-300g, and the weight of female mice can reach 170-260g. ③Meek temperament. ④ Strong resistance to infectious diseases. ⑤The incidence of spontaneous tumors is low. ⑥At present, the genetic status of Wisstar rats raised in various places varies greatly.

Main uses: Wide range of uses.

2. SD (Sprague Dawley, SD) rat

In 1925, it was bred from Wistar rats at Sprague Dawley Farm in the United States. It grows quickly and has good breeding performance. It is mostly used in safety tests and research related to nutrition and growth and development.

Coat color: albino

Main characteristics:

①The head is narrow and long, the tail length is close to the body length, the litter is large, and the growth and development is faster than that of Wistar. At 10 weeks of age, the weight of male mice can reach 300-400g, and the weight of female mice can reach 180-270g. ②The temperament is slightly more ferocious than the Wisar rat. ③ Strong resistance to diseases, especially respiratory diseases. ④The incidence of spontaneous tumors is low. ⑤ High sensitivity to sex hormones.

Main uses: This strain is sensitive to sex hormones and has strong resistance to respiratory diseases. It is widely used in pharmacology, toxicology, efficacy and GLP experiments, nutrition and endocrine system research.

3. Guinea pigs

Experimental animals guinea pigs are domesticated from wild guinea pigs in Peru.

Coat color: various, including white, black, sandy white, two colors, three colors, etc.

Main characteristics:

①Late-maturing animals. ②Precocious puberty. ③Estrus occurs frequently throughout the year, including postpartum estrus and postpartum pregnancy. ④ It cannot synthesize vitamin C by itself. ⑤ Strong ability to resist hypoxia. ⑥ Sensitive to antibiotics, especially penicillin, erythromycin, chlortetracycline, etc. ⑦ Sensitive allergic reaction. An animal model of anaphylactic shock can be easily replicated by injecting horse serum into guinea pigs. The degree of reaction of commonly used experimental animals to allergens: guinea pigs > rabbits > dogs > mice > cats > frogs. ⑧Have acute hearing with Pryor reflex (also known as auditory otomotor reflex). ⑨ Poor body temperature regulation ability and more sensitive to changes in ambient temperature.

Main purposes:

①Pharmaceutical and pharmacological research. ②Infectious disease research. ③Immunology research. ④ Nutritional research. ⑤Ear scientific research. ⑥Experimental studies on bleeding and vascular permeability changes. ⑦Guinea pigs have strong tolerance to hypoxia. Suitable for experiments on hypoxia tolerance and measuring oxygen consumption. ⑧Experimental pulmonary edema experiment.