Effects on Growth of Rat Offspring Born From Dams Treated Subcutaneously With a Surfactant, Polyoxyethylene(10)nonylphenyl Ether(np-10), During Lactational Period

Abstract

A surfactant NP-10 was administered subcutaneously to Jcl:Wistar female rats at dose levels of 5, 20 and 80 mg/kg/day from date of birth to day 21 after birth of F1 offspring to assess its effects on the growth, behavior and functions of the offspring. For F0 dams, scab formation and loss of hair at the test substance administration site were observed in all treatment groups and induration of the skin at the test substance administration site in the 20 and 80 mg/kg groups in general condition and necropsy findings at the end of the dosing period. In necropsy findings, in addition to these changes, hemorrhage and whitish change of the subcutis at the test substance administration site were seen in all treatment groups, adhesion to the somatic muscles and granulation of the subcutis at the test substance administration site in the 20 and 80 mg/kg groups, and swelling of the spleen and adrenals in the 80 mg/kg group. Reduction or a tendency for reduction in food consumption was also detected from the initial day of dosing (day 0) to day 17 after birth F1 offspring in the 80 mg/kg group. Body weight or the findings on the day after birth and day of weaning failed to reveal any evidence of an effect that could be ascribed to the test substance. In F1 born offspring, a decrease or tendency for decrease in body weight was observed from day 7 after birth in both sexes and for females during the gestation period in the 80 mg/kg group. However, body weight gains based on the weights at 4 weeks after birth or on day 0 of gestation in the 80 mg/kg group failed to reveal any difference from that in the control group. The observation on the day of birth and during the period of lactation, physical development test, reflex test, general condition, open-field test, water-maze test, reproductive ability test, observations at cesarean section, necropsy findings, organ weights, histopathological findings of females or males that did not achieve successful gestation, skeletal examination, and the observations at cesarean section and external examination of F2 fetuses failed to reveal any evidence that could be ascribed to the test substance. These results indicate that NP-10 had no effect on the behavior or functions of the offspring, although it affected the growth of the offspring born, under the conditions of this study. The non-effective dose level is considered to be 20 mg/kg for general toxicity of the dams and for their offspring.