Comparative responses of vaginal mucosa to chronic pyrimidinone-induced irritation

Intravaginal studies in guinea pigs, Cebus monkeys (Cebus apella), and beagles were made with an anti-herpes drug, 2-amino-5-bromo-6-phenyl- 4(3H)-pyrimidinone (ABPP). Concentrations of 5 to 40 mg/ml, suspended in saline or polyethylene glycol, were given for periods of 2 1/2 to 90 days. Very little gross evidence of injury was observed. Histologically, the regimens brought about increasing degrees of mononuclear cell infiltrations (histiocytes, lymphocytes, and plasma cells) in the vaginal lamina propria of the respective species. In the Cebus monkey and beagle the nonkeratinized vaginal lining became progressively thinned. The integrity of focal denuded areas was preserved by a process of homogenization in the lamina propria of the Cebus monkey. In contrast, the most severely affected areas in the canine mucosa were covered by what appeared to be a coagulated exudative layer. The effect of 90 days of treatment in the beagle did not noticeably increase the severity of the findings beyond that observed after 30 days. Considerable reversibility of the lesions occurred in guinea pigs held for 1 week and in Cebus monkeys held for 3 weeks posttreatment. Local cell-mediated immunity was believed to be implicit with the mononuclear cell infiltration in the lamina propria of the vagina.