Effects of lipopolysaccharide on the expression of proinflammatory cytokines and chemokines and influx of leukocytes in the hen ovary.

The aim of this study was to determine whether the expression of proinflammatory cytokines and chemokines in ovarian cells was changed to recruit heterophils and T cells in response to lipopolysaccharide (LPS), a gram-negative bacterial component. White Leghorn laying hens were intravenously injected with LPS or saline and their ovarian follicles and stroma were collected. Changes in the mRNA expression of IL-1β, IL-6, and CXCLi2 in the theca and granulosa layers and ovarian stroma were analyzed by quantitative reverse transcriptase PCR, whereas proteins of IL-1β and IL-6 were also identified by Western blot analysis. Localization of heterophil-like cells and CD4(+) and CD8(+) T cells was examined by general histology and immunohistochemistry. The expressions of IL-1β, IL-6, and CXCLi2 were significantly increased in the granulosa layer, theca layer, and stroma tissues by 3 to 6 h after LPS injection. Increase of IL-1β and IL-6 proteins in those tissues was also identified 12 h after LPS injection. The LPS stimulation resulted in the increased influx of heterophil-like cells and CD4(+) T cells, but not CD8(+) cells, in the theca layers of follicles. Saline injection affected neither expression of examined proinflammatory cytokines and chemokines nor frequencies of immunocompetent cells. These results suggest that ovarian follicular cells and stromal cells have the ability to express proinflammatory cytokines and chemokines, and their expression is upregulated by LPS in association with the recruitment of heterophil-like cells and T cells. These responses may play roles in local host defense in ovarian follicles.