engleski

Expression of nestin in human foetal testis

Nestin is an intermediate filament expressed mostly in nerve cells. It seems that this filament plays certain role in the radial growth of the axon. During the early stages of development, nestin is expressed in dividing cells in the central nervous system, peripheral nervous system and in muscular and other tissues [1]. Upon differentiation, nestin becomes downregulated and is replaced by tissue-specific intermediate filament proteins. In the adult normal human testis, nestin is expressed in some vascular endothelial cells, in a subset of peritubular spindle-shaped cells and some Leydig cells. In normal Leydig cells, nestin has been distributed in the perinuclear cytoplasm. Interestingly, this filament was also found accumulated in the crystalloids of Reinke [2]. In the developing testis of rat and mouse, the reaction for nestin is weak in the gonadal ridge, whereas the cells of the mesonephric mesenchyme show a prominent reaction for this filament. Later on, nestin has been found in the Sertoli cells. In the interstitial cells, nestin is expressed together with vimentin and desmin, and is most prominent in the differentiating myoid cells. After birth, nestin gradually disappears from the testicular cells and in the rat at puberty has been found only in the endothelial cells of some blood vessels [3]. Since there is a lack of data on the presence of nestin during the human foetal development, the aim of the current study was to investigate the expression of this intermediate filament in human foetal testis. A total of 39 human foetal testicles form 15th to 36th week of gestation were used in the study. The tissue samples were obtained during the routine paedopathological section of miscarried children during year 1994 (approved by the ethical committee).The samples were fixed in Bouin’s fluid, dehydrated and embedded in paraffin. Paraffin blocks were cut extensively in order to provide sections for hematoxylin & eosin (H.E.) and nestin immunohistochemical staining (IHC). H.E. stained sections demonstrated the existence of sex cords that had 40-50 μm in diameter and were composed of pre-spermatogonia and foetal Sertoli cells. The future lamina propria consisted of several gentle layers of peritubular cells. In general, sex cords and associated blood vessels in the interstitium grew progressively from 15th to 36th week of gestation achieving rather tortuous structures. Strong expression of nestin was noted in the cytoplasm of foetal Sertoli cells and some peritubular cells. Pre-spermatogonia seemed to be negative. No positive reaction could be noted in foetal Leydig cells. However, some fibroblast-like cells were positive, especially within the future tunica albuginea. The strong expression has been also found in interstitial blood vessels. The results obtained suggest the role of nestin in the development of human foetal Sertoli cells, some peritubular cells, blood vessels and fibroblast-like interstitial cells. Cells of blood vessels could generate future nestin-positive Leydig cells, as noted in the rat and mouse models.

foetal testis; nestin

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