Experimental inoculation of male mice with murine cytomegalovirus and effect on offspring

BACKGROUND: Murine cytomegalovirus (MCMV) was used to examine aspects of vi ral infection in male mice, and its possible transmission to their offsprin g. METHODS AND RESULTS: FVB/N mice inoculated intratesticularly with 5 X 10 (5) plaque forming units (PFU) of MCMV, developed peritoneal haemorrhagic e xudates, spleen hypertrophy and acute local infection. Infectiousness was d etected until 15 days post-inoculation (D15 PI) in the genital organs, and virus DNA up to D35 PI. Testicular endothelial and Leydig cells were infect ed, and peritubular cells severely damaged. Spermatogenesis was affected, b ut neither germ cells nor Sertoli cells were infected. No virus was found i n the epididymal epithelial cells. Viral DNA was detected in cells extracte d from vas deferens samples until D15 PI. Neither infectious virus nor vira l DNA were found in spermatozoa recovered from uterine fluid, fertilized oo cytes, blastocysts, fetal tissues or newborn animals following the mating o f infected males with uninfected females. CONCLUSIONS: MCMV harboured in th e male genital organs was not transmitted to their offspring, even when mat ing occurred during the acute phase of CMV disease. Although the infection may have had an impact on spermatogenesis, fertility was not affected. Thes e results do not support the hypothesis of conceptus MCMV infection by the fertilizing spermatozoon in natural conception.