Spatial expression of chemokines and cytokines mRNA in the largest preovulatory follicle of chicken

In the present experiment, we studied the spatial expression profiles of chemokines and cytokines mRNA in the granulosa (F1Gr) and theca (F1Th) layers of the largest preovulatory follicle in chicken using semi-quantitative PCR. The mRNAs of IL-1β, IL-6, GM-CSF, chCXCLi2, chCCLi2, chCCLi4, chCCLi7, IFN-γ, IL-4, IL-13, IL-10 and TGF-β2 were expressed in the granulosa (F1Gr) and theca (F1Th) layers of the largest preovulatory follicle. However, the transcripts of IL-2 were not detected in any of the samples tested. Significantly higher levels of IL-6 and GM-CSF mRNA expression were noticed in F1Gr when compared to F1Th layer. Expression of chCXCLi2, a CXC chemokine, was almost similar in F1Gr and F1Th layers. However, the expression of CCL chemokines i.e. chCCLi2, chCCLi4, chCCLi7 mRNAs were almost 2 folds higher in F1Th layer in comparison to F1Gr layer. The expression of Th2 cytokines (IL-4 and IL-13) mRNA was noticed in F1Gr and F1Th layers with higher levels in the former. Expression of IFN-γ mRNA was noticed in F1Gr and F1Th layers. Significantly higher level of TGF-β2 expression was observed in F1Th in comparison to F1Gr layer. It was concluded from the present study that the mRNA expression of cytokines and chemokines are differentially regulated in the granulosa and theca layers of the largest preovulatory follicle in chicken.