Experimental study on oncogenicity of Anstolochia manshuriensis Kom in rats

ABSTRACT

Objective To observe the oncogenetic process and pathological features of tumor induced by Aristolochia manshuriensis Kom. in rats. Methods Male Sprague-Dawley rats were divided into two groups. The rats in experimental group( n = 30) received by gastric tube about 20 mg ? kg-1 ? d-1 aristolochic acid contained in the extract of Aristolochia manshuriensis Kom. for 5 days in the 1 st week, and then 15 mg ? kg-1 ? d-1 for 7 days in each group were killed at the end of 1st, 4th, 8th, 12th and 16th week, respectively. Each rat was autopsied. Ttrachea, thyroid, heart, lungs, liver, spleen, pancreas, stomach, small and large intestine, kidneys, ureters, bladder and testes were excised and fixed in 10% formalin for histological examination. Results Of the examined organs in the rats of experimental group only forestomach and bladder developed carcinomas. Forestomach: hyperplasia and atypical hyperplasia of squamous cells were found at the end of the 4th week. Squamous cell carcinoma was detected in some rats from the end of 8th week and in all rats of the 16th week. Bladder: Hyperplasia, atypical hyperplasia and carcinoma of transitional cells were found from the end of the 8th week, and this carcinoma was present in all rats at 16th week. No tumor was found in all examined organs in the rats of control group. Conclusions Aristolochia manshuriensis Kom. is a potent oncogen which can induce the squamous cell carcinoma in forestomach and the transitional cell carcinoma in bladder. Its oncogenicity is time-dependent and may be organ-specific.