The Effects Of Prenatal Social Stress On Cellular Immunity In Adult Rats

Exposure to prenatal stress can impair the development of endocrine, nervous systems and future behavior of mammals. However, the impact on their immune system is poorly investigated and little is known about whether prenatal social stress actually affects immune functions of adult offspring of both sexes.The aim of the present study was to determine the effects of prenatal social stress on cellular immunity in adult rats of both sexes, by using a social defeat model in pregnant SD (Sprague-Dawley) rats. Pregnant rats were exposed to social defeat stressor, twice daily from gestational day14(G14) to day20(G20). Experiments were performed on male and female offspring aged70-80days.We found that prenatal social stress increased the relative numbers of lymphocytes and decreased the relative and absolute numbers of monocytes in female rats, but the changes were not statistically significant in males. Prenatal social stress decreased proliferation of splenic lymphocytes to LPS in male rats, while the decrease was not significant in females. Prenatal stress decreased proliferation of splenic lymphocytes to ConA of both sexes, but the changes were not significant. The proliferation of blood lymphocytes in response to ConA and LPS was lower in male and higher in female PS groups compared with their controls, while the changes were not statistically significant. These data indicated the gender differences of cellular immunity in response to prenatal social stress. Furthermore, some basal gender differences of immune parameters we tested were also observed, and some of them could be changed by prenatal stress. On the one hand, the gender differences of some parameters that were not significant in control group became statistically significant in PS group. For example, prenatal stressed females had higher lymphocyte percentage and lower red blood cells than PS males, while the differences in control group were not significant. On the other hand, the gender differences of some parameters, such as CD4+and B lymphocytes percentage, were statistically significant in control group, while the differences became not significant in PS group.In conclusion, our results demonstrated that social defeats of pregnant SD rats from G14to G20, could induce a long-term alteration in cellular immune functions of adult offspring, and these alterations discriminated between different genders, thereby possibly making them more vulnerable to some diseases.