Fig. 4

Cytokine receptors expression by isolated ependymal cells. Gene expression for the cytokine receptors IL-1β (IL-1βR1) and TNFα (TNFαR1) was quantified in pure ependymocytes by qPCR, relative to the expression of the housekeeping gene GAPDH. The expression of genes specific of ciliated cells (FOXJ1 and IIIG9) was also measured to confirm the identity of ependymocytes isolates. As a reference to compare with, the expression of the same genes was measured as well in choroid plexus (obtained from the lateral ventricles) and in brain parenchyma. Bars are the mean + s.d. of n = 4–7 cell isolates/tissues obtained from different rats. The high expression of IIIG9 and FOXJ1 in ependymal cells compared to the brain parenchyma indicates the enrichment of these samples in this cell type. Choroid plexus cells shared with ependymocytes the high expression of the FOXJ1, but not that of IIIG9, which was exclusively expressed by ependymal cells. The expression of the cytokine receptors IL-1βR1 and TNFαR1 was significantly higher in ependymal cells and choroid plexus, compared with the expression in the brain parenchyma. Ependymal cells expressed both receptors at a higher level than choroid plexus cells. Kruskal–Wallis test revealed differences (P < 0.005) between the means of the groups; pairwise comparisons were then carried out with Mann–Whitney U test. Letters a, b, c, d and e above bars indicate the absence (if the same letter appears) or presence (if different letters appear) of a statistical difference (P < 0.05). Data points have been omitted in those bars that are extremely small