[Effects of hyperbaric environment on the course of experimental lymphocytic choriomeningitis (LCM) in the mouse (author's transl)].

During a week, adult Swiss mice inoculated with LCM virus were exposed to hyperbaric environment (51 ATA) in He-O2 mixture. This exposure delayed the mortality by virus infection for 5-6 days and/or lowered or abolished the specific cerebral pathology. However, at the moment of death, the infectious titer of virus in the brain of exposed mice was not significantly decreased. Some physico-chemical factors involved in hyperbaric environment were investigated in order to determine their possible role in inducing the delayed mortality. Temperature has no effect on the course of experimental LCM in the mouse while He-O2 mixture at atmospheric pressure aggravate the viral disease. Pure O2 applied at 2 ATA intermittently has some beneficial effect but only on specific cerebral alterations. Thus, it seems likely that "per se" hydrostatic pressure and/or an hyperabaric helium specific effect is responsible for the delay of mortality after hyperbaric exposure. Possible mechanisms leading to this delay, i.e. a transient abolition of immunologic response of mice to LCM virus, are briefly discussed.