Epidermal growth factor and fibroblast growth factor 2 cause proliferation of ependymal precursor cells in the adult rat spinal cord in vivo

Abstract

We investigated the mitogenic effect of continuous intrathecal infusion of epidermal growth factor (EGF) or fibroblast growth factor 2 (FGF2) on ependymal precursor cells of the adult rat spinal cord in vivo. Either EGF, FGF2, EGF plus FGF2, or artificial cerebrospinal fluid (aCSF) was infused at a flow rate of 0.5 μl/h (15 ng/h of EGF or FGF2) for 3 or 14 days into the intrathecal space at T1 through a catheter attached to an osmotic minipump. To assess proliferation, the bromodeoxyuridine (BrdU) labeling index (LI) in the ependyma at T1 was calculated at 3 or 14 days. At 3 days there was no statistical difference in LI between these groups, but at 14 days the LI was significantly higher in the EGF plus FGF2 group (27.2% ± 16.0%) than in the aCSF group (5.4% ± 4.7%; p < 0.05). With EGF alone or FGF2 alone, the LI increases were not significantly different from the aCSF group. With EGF plus FGF2 for 14 days, some BrdU-positive cells in the ependyma also expressed nestin. These results suggest that the intrathecal infusion of EGF plus FGF2 has a mitogenic effect on precursor cells in the ependyma of the adult rat spinal cord.