Chemical carcinogenesis in rat (Rattus norvegicus) submandibularGland using DMBA

ABSTRACT

Objective: This paper aims to investigate the neoplasms produced after the injection of 9,10-Dimethyl-1,2-benzantracene (DMBA) in rat submandibular glands. Material and Methods: Twenty eight 3-month old male rats (Rattus norvegicus), approximate weight of 300g, were used. The animals were divided into four groups of seven subjects each. After anesthesia and proper preparation, all animals were injected with 0.1ml of 2% DMBA in the left submandibular gland. By the end of the fifth, tenth, fifteenth and twentieth weeks, the animals were sacrificed by lethal doses of anesthetics. Results: The results in the fifth week presented seven cases of chronic sialadenitis. After ten weeks, one case of ductal cell atypia was evident, along with two cases of squamous cell carcinoma and four cases of chronic sialadenitis. Between the fifteenth and twentieth weeks, the cases were diagnosed as follows three cases of hyperemia; three cases of squamous cell carcinoma; one case of sarcoma and seven cases of carcinosarcomas. Conclusions: This study allowed the investigation of glandular carcinogenesis after DMBA injection, from the beginning of inflammatory changes to the neoplastic manifestation of tumors. Salivary carcinogenesis can provide beneficial material for the study of rare human salivary gland neoplasms like sarcomas, carcinomas and carcinosarcomas.