Lobe Identity in the Mongolian Gerbil Prostatic Complex: A New Rodent Model for Prostate Study

Abstract

Knowledge of structural and physiological differences among the prostatic lobes (PL) is the basis for development of experimental studies in traditional laboratory rodents. Although Mongolian gerbil reproductive organs have been increasingly investigated, its prostate structure is far from being properly known, and investigations of this organ focused on the ventral lobe (VL). Thus, the present study provides a thorough morphological description of prostatic complex in the male adult gerbil on the basis of topographic, histological, and ultrastructural analysis and ductal branching. Like other rodents, four pairs of PL were observed. However, in contrast to the rat and mouse, the VL is the least voluminous component and the dorsolateral lobe (DLL) is the most prominent and spatially isolated from remaining PL. The occurrence of a dorsal lobe (DL), hidden between bladder and insertion of seminal vesicles, has not been mentioned in previous reports with Mongolian gerbil. Collagenase digestion followed by microdissection revealed that, except for DL, which has a tubularacinar organization, all PL exhibit tubular organization and variable ductal branching. Distinct histological and ultrastructural features such as secretory epithelium, aspect of luminal secretion and stromal organization are reported for each PL and are confirmed by morphometric and stereological methods. Histological sections showed at least three intralobar segments in VL and DL. Ultrastructural analysis evidenced that, although luminal epithelial cells of PL share typical features of exocrine secretory cells, there are striking lobe phenotypical variations. Both merocrine and apocrine pathways are observed in variable rates in all PL, with the predominance of the former in the DLL and the latter in the CG. The morphological observations presented herein point to distinct structural identities for each PL, which probably reflects specific functional compromise of seminal fluid secretion. These data also point to the gerbil as a good model for investigations concerning the regulation of prostate development and homeostasis, mainly with regard to the dorsal and dorsolateral PL.

Neonatal Gonocyte Differentiation in Mongolian GerbilMeriones unguiculatusInvolves Asynchronous Maturation of Seminiferous Cords and Rapid Formation of Transitional Cell Stage

“…This gerbil has proved to be a useful animal model for investigations of both the male prostate complex (Rochel et al, 2007) and female prostate (Santos et al, 2008). In the Mongolian gerbil, spermatogenesis begins at Week 2 of life and sexual maturity occurs at Week 10 (Ninomiya and Nakamura et al, 1987).…”

Differentiation of Leydig cells in the Mongolian gerbil

“…Additionally, hormonal variations on estrous cycle indicate peculiarities in the control of reproductive functions in gerbil (Fochi et al, 2008). Analysis of male prostatic complex in this specie revealed that the most voluminous component is the dorsolateral lobe whereas in rat and mouse is the ventral one (Rochel et al, 2007). Whereas some aspects of reproductive biology of gerbil have been well exploited in literature, others remain unknown, such as the ones concerning postnatal testicular development.…”

“…The Mongolian gerbil Meriones unguiculatus has been widely used in several areas of biomedical research (Cao et al, 2005;Ter-Mikaelian et al, 2007;Wiedemann et al, 2009) with an increasing interest on morphophysiology of genital system (Fochi et al, 2008;Rochel et al, 2007;dos Santos et al, 2003;Segatelli et al, 2004). The gerbil has been adopted in our laboratory as an excellent rodent model for studies on female prostate gland due the high incidence of this organ in comparison with other rodents (dos Santos et al, 2003).…”

Modulação androgênica e estrogênica na próstata: uma abordagem em modelos experimentais de roedores com enfoque na biologia estrutural

“…Além disso, as análises iniciais indicavam que os lobos prostáticos do gerbilo apresentavam maior proximidade, sugerindo maior grau de semelhança com a próstata humana (8). Em adição, a análise dos tecidos associados à uretra de fêmeas revelou a existência de glân-dulas parauretrais (à semelhança das glândulas de Skene em humanos), que após estudos estruturais, bioquímicos e ultraestruturais nos levaram a concluir que se tratava de um complexo prostático feminino, mais volumoso em comparação com outros roedores de laboratório (9).…”

“…Além disso, tal organização anatômica diferia da descrita para a maioria dos roedores, em que o LL também era observado. Visando a melhor entendimento da organização estrutural do complexo prostático do gerbilo e suas possíveis implicações funcionais, bem como a comparações com modelos clássicos de roedores para o estudo da próstata, realizou-se uma ampla descrição desse complexo (8). Para isso, além de se empregar os métodos morfológicos e ultraestruturais de alto padrão, foram implementados métodos de microdissecção, aliados à digestão enzimática.…”