Histological and immunohistochemical study of albino rat filum terminale at different postnatal ages

ABSTRACT

It is difficult to find accurate data on the normal histology of the filum terminale because the previous studies dealing with its structures are insufficient. The present work aimed to study the histological structure of the filum terminale of the albino rat at different postnatal ages. Thirty six albino rats at different ages were divided into six groups; full term, two weeks, one month, adult [three months], six months and one year. The filum terminale was cut in situ at the level of the iliac crest, excised from its attachment to the coccyx and fixed. The specimens were processed for light and immunohistochemical Study. All sections were examined by light microscope. Filum terminale of the albino rat consisted of ependymal canal surrounded by central and marginal zones. The canal was variable in site, shape and lining ependymal cells according to age. The central and marginal zones contained neuron and glial [oligodendrocyte, microglia and astrocyte] cells immersed in neuropil fibers which changed with the advance of age. Negative Glial-Fibrillary-Acidic Protein [GFAP] reaction in the full term filum terminale group. In two weeks group; there was positive reaction. In one month group there was strong reaction which persisted with gradual decline in three and six month groups. In one year, GFAP reaction was scanty positive or even negative. The albino rat filum terminale contains neurons, glial cells, GFAP-positive glial fibers and neuropil fibers. Structural changes occur in these constituents with age