THE EFFECTS OF PSK, A BIOLOGICAL RESPONSE MODIFIER, ON CONGENITAL OCULAR ABNORMALITIES INDUCED BY X-RAY-IRRADIATION

The antiteratogenic effects of PSK, a biological response modifier, we re examined using histological and developmental analysis. The whole b odies of pregnant mice were irradiated with X-rays and injected with P SK within ten minutes after irradiation on day 7 of gestation (E7). Th e foetuses on E18 were examined and a high incidence of malformations were observed in X-ray irradiated embryos. Microphthalmia was the most frequent malformation. PSK administration suppressed the X-ray irradi ation-induced ocular anomalies in not only the frequency, as deduced b y external observation, but also in histopathological changes in the r etina, lens, and cornea. In particular, the incidence of lens aplasia was significantly decreased by PSK administration. Developmental analy sis using E10 and E13 embryos revealed that the decrease in the incide nce of histopathological changes was first observed within 72 hours af ter PSK administration. In addition, X-ray irradiation-induced early f oetal death (E10-13) was also suppressed by PSK administration. The po ssible mechanisms of the antiteratogenic effects of PSK are discussed.