IADR Abstract Archives
4NQO-Induced Oral Carcinogenesis in Wistar Rats: a Systematic Literature Review
Objectives: To establish a guide for best practice on the use of 4NQO-induce oral carcinogenesis model in Wistar rats by critically reviewing the available literature.
Methods: A systematic search were carried out in the Medline Ovid, PubMed, Web of Science, and Scopus databases. Only studies performed with Rattus norvegicus (Wistar), with histological assessment and results from the 4NQO group presented individually were included.
Results: Of the 2,544 studies initially filtered, 35 met all selection criteria. In 22 (62.9%) studies 4NQO was offered systemically in the animals' drinking water, at a mean concentration of 30.2 (SD±15.9) ppm, for a mean of 20.8 (SD±7.8) weeks. The other 13 (37.1%) studies used topical administration of 4NQO diluted in propylene glycol, painting the oral mucosa of the rat with the carcinogen, three times a week (100%) during 16.8 (SD±7.0) weeks. Clinical assessment was poorly described and consisted mostly of qualitative description. Histological evaluation varied, but overall epithelial hyperplasia was reported in 23 (65.7%) studies, epithelial dysplasia in 29 (82.9%), carcinoma in situ in 5 (14.3%), and invasive carcinomas in 27 (77.1%). In studies with multiple evaluation times, epithelial hyperplasia was observed between 2 and 3 weeks, dysplasia between 7 to 16 weeks, and invasive tumors with at least 8 weeks and at most 26 weeks of 4NQO administration. Two (9.1%) systemic studies and three topics (23.1%) studies achieved 100% of carcinoma incidence. In general, care with 4NQO application, preparation, adverse effects and loses were poorly reported.
Conclusions: Considering the heterogeneity of the results presented here, this review confirms the efficiency of 4NQO in inducing oral carcinogenesis at certain time intervals and dosages. Care with solution preparation and adverse effects reporting needs to be improved and standardization of clinical and histopathological results is desired.
Methods: A systematic search were carried out in the Medline Ovid, PubMed, Web of Science, and Scopus databases. Only studies performed with Rattus norvegicus (Wistar), with histological assessment and results from the 4NQO group presented individually were included.
Results: Of the 2,544 studies initially filtered, 35 met all selection criteria. In 22 (62.9%) studies 4NQO was offered systemically in the animals' drinking water, at a mean concentration of 30.2 (SD±15.9) ppm, for a mean of 20.8 (SD±7.8) weeks. The other 13 (37.1%) studies used topical administration of 4NQO diluted in propylene glycol, painting the oral mucosa of the rat with the carcinogen, three times a week (100%) during 16.8 (SD±7.0) weeks. Clinical assessment was poorly described and consisted mostly of qualitative description. Histological evaluation varied, but overall epithelial hyperplasia was reported in 23 (65.7%) studies, epithelial dysplasia in 29 (82.9%), carcinoma in situ in 5 (14.3%), and invasive carcinomas in 27 (77.1%). In studies with multiple evaluation times, epithelial hyperplasia was observed between 2 and 3 weeks, dysplasia between 7 to 16 weeks, and invasive tumors with at least 8 weeks and at most 26 weeks of 4NQO administration. Two (9.1%) systemic studies and three topics (23.1%) studies achieved 100% of carcinoma incidence. In general, care with 4NQO application, preparation, adverse effects and loses were poorly reported.
Conclusions: Considering the heterogeneity of the results presented here, this review confirms the efficiency of 4NQO in inducing oral carcinogenesis at certain time intervals and dosages. Care with solution preparation and adverse effects reporting needs to be improved and standardization of clinical and histopathological results is desired.