动物模型 z-bo 2020-08-04 503

　　Peroxide hydrogen peroxide, hydroquinone, monobenzophenone and other skin depigmenting agents are used to artificially cause animal depigmentation and simulate the pathological symptoms of vitiligo.

　　[Modeling mechanism] Hydrogen peroxide has strong oxidizing properties and affects the signal transmission in cells in various ways. Excessive accumulation of hydrogen peroxide in the epidermis can cause oxidative stress, interfere with the biopterin cycle, inhibit related enzyme activities and directly or indirectly destroy melanocytes. Hydroquinone has a depigmentation effect on the skin. Since the mechanism of action is to competitively inhibit tyrosinase activity, tyrosine will not be converted into dopa and dopaquinone, thereby inhibiting the synthesis of melanin. Some people think that the decolorization of hydroquinone is essentially tyrosinase-mediated cytotoxicity. Hydroquinone molecules easily diffuse into the melanocytes of melanocytes, while inhibiting the production of melanin. Hydroquinone is oxidized under the action of tyrosinase to produce toxic substances based on hydroquinone, causing cells death. Monomer benzophenone is a skin bleaching agent, which will form quinone hapten after contact with the skin, inhibit tyrosinase activity, reduce melanin production and cause skin discoloration. Monobenzophenone bleaching took place on site.

　　[Characteristics of the model] When hydrogen peroxide is administered to guinea pigs, the dark skin of the guinea pigs can be seen bluish with the naked eye, white spots appear even if taken for a long time, and even the pigment of hair loss can be seen. It can be seen under the microscope that the melanin in the spinous process layer and the follicle is consumed. The top of the follicle is white, the center is yellow, and the bottom is black. At the same time, monoamine oxidase increased while cholinesterase decreased.

　　After giving a black cat 30 mg/kg hydroquinone for 6-8 weeks, the cat’s hair turned white. Hydroquinone was applied to guinea pigs and BALB/c mice by subcutaneous injection or feeding, and discoloration of the hair of the test animals was observed. After topical application of monobenzophenone in 57 melanoma mice C57BL/6B16, the local and distant non-contact areas appeared pigmentation, and the growth of melanoma was inhibited. 60% of mice survived without tumor after 100 days.

　　[Model evaluation and application] Chemical decolorization can cause vitiligo-like decolorization locally or remotely, thereby changing the levels of monoamine oxidase and cholinesterase. Such models can be used to evaluate drug efficacy. Monobenzone is externally applied to the C57BL/6B16 model of melanoma mice, mainly for studying the relationship between vitiligo and melanoma and the treatment of melanoma. Although monobenzophenone can cause vitiligo in healthy people, the stability and persistence of this pigmentation still needs further research. It should be noted that monobenzophenone cannot induce vitiligo in non-melanoma mice.