| [Objective] Study the laws and features of4-Nitroquinoline1-oxide on inducing the tongue mucosa cancerization of C57BL/6mice so as to provide reliable animal models for the later study of pathogenesis of tongue cancer and identification of new prevention and therapy targeting.[Method]1. Sort858-week-old female C57BL/6mice randomly into distilled water control group (n=5),1,2propylene glycol control group (n=5), and the experimental group (n=75); sort75mice of the experimental group randomly into15cages with5mice per cage. From the beginning of experiment (w=0week), kill the mice in cage1of experimental group, and continue to kill one cage of mice in the experimental group every two weeks until the28th week.2. Dissolve4NQ0in500μg/ml stoste prepared with1,2propyiene glycol, and keep it in a fridge whose temperature is4℃. Dilute the stoste into50μg/ml solution with distilled water before using. Apply the diluted solution to the mice in experimental group until the12th week, after which all mice in experimental group and1,2propylene glycol groups are fed with distilled water till the28th week.3. Decapitate the mice of experimental group every two weeks, and take photos of and weigh them before killing. Cut the mice’s fresh tongues as soon as they are killed, measure the tongues, observe general pathological changes of the tongues, and cut these tongues longitudinally into halves from the middle line with one half stored in10%formaldehyde solution and the other half dipped liquid nitrogen rapidly and transferred to a fridge at-80℃for further study. Having killed all the mice, select3cases for paraffin section randomly from the tongues of mice killed in each distilled water control group and1,2propyiene glycol control group in week0,4,8,12,16,20,24,28. Cut the tongues into4μm consecutive sections and stain them using HE coloration after dehydration of gradient ethanol and paraffin embed.4. Observe each section with optical microscope, record pathological changes of different stages, and take photos of them.[Result] As the use of carcinogen gets prolonged, white plaques and granular and mamillaryhyperplasia occur at the dorsum of tongue.8weeks later since experiment,73.3%of the cases were simple hyperplasia; in the12th week, such figure is42.8%, and minimal abnormal hyperplasia cases take up52.4%; when it comes to16th week, minimal and moderate abnormal hyperplasia take the majority of all with respective percentage of36.8%and42.1%. Besides, it is the first time that3severely abnormal hyperplasia cases have been observed, which take up15.8%of the total; four weeks later28.6%of cases are moderate abnormal hyperplasia,42.9%are severely abnormal hyperplasia, and23.8%are preinvasive carcinoma; in the24th week, severely abnormal hyperplasia and preinvasive carcinoma become majority, taking40%and45%of the total cases respectively. And1case,5%, is diagnosed as early-stage invasive carcinoma; in the28th week when the experiment ends, canceration rate of periglottis has reached as high as90%.[Conclusion] Tongue mucosa canceration of mice can be induced using4NQO drinking water method. Carcinogenic process in this experiment lasts long, and animals’tumor incidence reaches up to100%. Cancer induction mechanism is a simulation of natural generation process of human tumor, and pathological process is similar to that of human tumor. As a result, it is an ideal animal model for tongue cancer experiment. |
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