The Mycoplasma is considered cosmopolitan and can be disseminated through international trade of animals, industrialized semen and embryo transfer products. The expansion of cumulus cells is used as a parameter for evaluating cattle oocytes cultivated in vitro, and their morphological changes are representative. The aim of the present study was to evaluate the interaction of Mycoplasma bovigenitalium with primary-culture cumulus cells, after the in vitro maturation period. Cumulus complex oocytes (COCs) obtained through follicular puncture of ovaries from a cattle slaughterhouse were divided into two groups to be matured for 24 hours in the maturation medium (TCM 199 + hormones) in a climate controlled chamber at 38º C, 5% CO2, and 95% humidity. Subsequently, the oocytes were removed from the plates, which remained with only the cumulus cells attached. With the monostratum cell formed, one group was infected with 30 ºL (5 x 10(6) cells/mL) M. bovigenitalium, replicated in modified Hayflick medium at 37º C in a mycroaerofilic chamber, while the other was kept as a control. The results showed that with 24 hours of exposure to the pathogen, the cultures showed a small number of rounded and grainy cells, when compared to the controls. This effect persisted until the 7th day, when a process of cell detachment began. It can be concluded that a mycoplasma contamination may be imperceptible to the manipulations of FIV, because cells infected by this group of bacteria present no cloudiness in the culture field, and when they do not lyse the host cell, they make it more susceptible to environment and other infectious agents.
Mycoplasma bovigenitalium; cumulus complex oocytes (COCs); primary culture; in vitro fertilization (IVF)