Abstract:
The cellular composition of the testicular capsule, seminiferous peritubular tissue, the epithelia as well
as periductal muscle cell layers of the excurrent ducts was studied, in sexually mature and active Masked
Weaver (Ploceus velatus) birds of the passerine family, Ploceidae. Ultrastructure of the contractile cells
in the testicular capsule, peritubular and periductal tissues showed that these cells were smooth muscles
of typical morphological characteristics. Variability in the immunohistochemical co-expression of
microfilaments and intermediate filaments in the different tissues was evident. Actin and desmin proteins
were co-expressed immunohistochemically in the testicular capsule and seminiferous peritubular
smooth muscle layer. Actin was singly and very weakly expressed in the rete testis epithelium while
cytokeratins and desmin were co-expressed in the epithelium of the excurrent ducts. The periductal
muscle layer of all ducts of the epididymis, the ductus deferens as well as the seminal glomus, strongly
co-expressed actin and desmin. Vimentin was absent in all cells and tissue types studied. There is clear
evidence that the tissues of the male gonad and its excurrent ducts in the Masked Weaver, as has been
reported for members of the Galloanserae and Ratitae, contain well-formed contractile tissues whose
function would include the transportation of luminal through-flow from the testis into, and through, its
excurrent ducts. The microtubule helix in the head and of the mid-piece, of elongating spermatids, as
well as of the mature spermatozoa in the various excurrent ducts, including some spermatozoa in the
seminal glomus, also co-expressed these three proteins.
