CHANGES IN THE FREQUENCY OF SPLENIC IMMUNOCOMPETENT CELLS IN RATS EXPOSED TO CARBON-MONOXIDE DURING GESTATION

The aim of the present study was to evaluate whether prenatal exposure to relatively low concentrations of carbon monoxide (CO) may alter th e frequency of splenic cells either: in young (15 - 21 days) or in age d rats (18 months). Wistar female rats were exposed to 75 and 150 ppm of CO from day 0 to day 20 of pregnancy, respectively. The results sho w that prenatal exposure to 150 ppm of CO significantly decreases the number of leucocyte common antigen (LCA+) cells in 21 day old male rat s, whereas other cellular populations, such as macrophages, Major Hist ocompatibility (MHC) II cells, T and B lymphocytes display only a tren d towards a reduction without achieving statistical significance. The alterations in LCA+ cell frequency produced by gestational exposure to CO were reversible. These data further extend previous findings showi ng that rats prenatally exposed to moderate concentrations of CO exhib it subtle immunological changes in the absence of overt signs of toxic ity.