EFFECT OF INDOMETHACIN ON ULTRAVIOLET RADIATION-INDUCED RECURRENT HERPES-SIMPLEX VIRUS-DISEASE IN GUINEA-PIGS

Exposure to u.v. radiation increases the local level of prostaglandins which may play a role in u.v. radiation-induced herpes simplex virus (HSV) recurrences. We used the guinea-pig model of u.v. radiation-indu ced recurrent genital HSV-2 disease for examining the effects of indom ethacin, a prostaglandin inhibitor, on u.v.-induced recurrences. In th e first experiment, performed 100 days after HSV-2 inoculation, treatm ent with indomethacin for 5 days begun 24 h before u.v.-irradiation de creased the proportion of animals developing HSV disease recurrences f rom 11/13 (84.6%) to 2/13 (15.4%) (P < 0.001). In the second experimen t, performed 135 days after HSV-2 inoculation, treatment with indometh acin for 5 days begun 24 h before u.v.-irradiation decreased the numbe r of animals developing recurrences from 12/21 (57.1%) to 5/21 (23.8%) (P < 0.05). Five days of indomethacin treatment begun 4 h after u.v.- irradiation. however, did not reduce the percentage of animals develop ing disease recurrences but did decrease the mean number of days with recurrent lesions in animals that developed recurrences. Our data sugg est that indomethacin may modify u.v. radiation-induced recurrent lesi ons by decreasing viral reactivation when given before u.v. radiation exposure or by reducing prostaglandin-induced immunosuppression when g iven before or after exposure. Future studies are needed for evaluatin g indomethacin prophylaxis for recurrent HSV disease when prolonged u. v. radiation exposure is anticipated.