Establishment of a rat model of laryngeal precancerous lesions induced by 4NQO smearing

Abstract

Objective: To establish a rat model for laryngeal precancerous lesions histologically and pathologically comparable to the human counterpart. Methods: Thirty-six Wistar rats were randomly divided into experimental group and control group, with 18 rats in each group, and 1% 4-nitroquinoline-1-oxide (4NQO) solution and saline were respectively applied to the laryngeal mucosas of rats in two groups. During subsequent 20 weeks, the changes of laryngeal mucosas were regularly observed with naked eyes and endoscope and lesions were determined by histology. SPSS 22.0 software was used for statistical analysis. Results: The food intake, water intake and body weight of the rats in the experimental group were lower than those in the control group, with statistically significant differences (all P<0.05). White plaque, superficial ulcer, erosion and miliary particles were present in the larynxes of rats in the experimental group, with histological manifestations of atypical hyperplasia or carcinoma in situ, and normal epitheliums were shown in the control group. The number of Ki67 positive cells in the laryngeal mucosas of rats in the experimental group at the 4 th, 8 th, 12 th, 16 th, and 20 th weeks were 13.5±2.4, 35.6±5.8, 53.4±8.3, 78.8±11.6, 80.6±12.4, respectively, no Ki67 positive cells were found in the control group at individual time points, and the differences were statistically significant (t=9.74, 10.63, 11.14, 11.77, 11.26, respectively, all P<0.01). Conclusion: 4NQO can credibly cause rats laryngeal precancerous lesions, which morphologically and histologically mimic laryngeal carcinnogenesis. This method is practical, easy and reliable to prepare the animal model of laryngeal precancerous lesions.