[abstract] HYPERBARIC OXYGEN TREATMENT OF PREGNANT MICE (Mus domesticus): EFFECTS ON EMBRYO SURVIVAL AND POSTNATAL NEUROMUSCULAR DEVELOPMENT OF PUPS.

Abstract

BACKGROUND: The effects of prenatal exposure to hyperbaric treatment (HT) on early development of mice was examined in this preliminary study. METHODS: Multiparous females were paired with males of proven fertility. After 7 days males were removed and females were randomly allocated to the following treatment groups (N=10 for each group): A) 100% oxygen (2.8 ATA x 80 min.); B) air (2.8 ATA x 80 min.) and C) not compressed (i.e. 80 min. of housing into the chamber). All animals were daily treated for 13 days. The number of delivering females, weight and number of pups at birht were recorded. Ethological analysis of early development was carried on by daily recording the following behaviors of pups: righting, geotaxis and cliff avoidance relfexes and rooting behaviors (see Fox. 1965). Postnatal physical maturation (e.g. growth, eye and ear opening) was also recorded. RESULTS: Oxygen treatment reduced the proportion (50% vs 100% of controls) of females delivering (p= 0.03 Fisher's exact probability test). HT did not affect postnatal body growth of pups but strongly influenced all the reflexes (p<0.0001 ANOVA) depending on pups' age. HT delayed fur appearance, ear and eye opening. In general, in comparison to air, oxygen treatment resulted in more marked effects for virtually all the behavioral and developmental recorded measures. CONCLUSIONS: Clinical HT of pregnant mice can induce abortion and affects motor development and physical maturation of pups, thus suggesting a toxic effect on neuroanatomical substrates during uterine life. Consequently further ethoexperimental analysis (i.e. ultrasound production, learning and social behavior) of prenatally HT exposed young and adult mice can be used to evaluate the possible brain damage and impairment of neurological functions.