MORPHOLOGICAL OBSERVATIONS ON THE TESTES ... - Unesp

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OLIVEIRA, c.; ZANETONI, C. & ZIERI, R. Morphological observatioos 00 the testes of Phvsalael11l1s ellvieri (Amphibia, Ao"ra). ReI'. Chil. Anat., 20(3):263-268, 2002.them typical shapes. The Sertoli cells, when associated withthe spermatogonia lI, present a nucleus with more elongatedshape, still semilunar or falciform.Spermatocytes - they are the result from the spermatogoniaII ditferentiation, the spermatocytes I are cells just smallerthan the spermatogonia I. In its nucleus, the chromatin isslightly condensed. The spermatocytes II are haploid cells andquite smaller than the previous, and they are originated in thefirst meiotic division. Generally, the spermatocytes areobserved in different phases of the first meiotic division,presenting different degrees of compactation of the nuclearmaterial. In this stage, the Sertoli cells are more voluminous,the nuclei are less condensed and present the tendency toassume intermediate shape, between elongated and ovoid.Spermatids - whenthe spermatocytesII pass throughthesecond meiotic division, they form the spermatids. These, inthe primary stage or as round spermatids I, are differentiatedfrom the cysts of the spermatocytes II when some cells showthemselves slightly elongated. The spermatids II or elongatedare cells with compacted and elongated nuclei, whose cysticarrangement is altered to be organized in bundles sustainedby the Sertoli cells. In this moment, the nucleus of the Sertolicells finds itself as oval or rounded, with chromatin looselydistributed, besides the evident and central nucleolus.Spermatozoa - they are characterized by a extraordinary nuclearcompactation and a cytoplasmic reduction. Thespermatozoon head, represented mainly by the nucleus, isslender; and, in general, it turns to the nucleus of the Sertolicell, in opposition, the tail has a filamentous appearance andis slightly stain, and, generally, turns to the luminar area of theseminiferous locule. The spermatozoa in development arearranged in bundles very well organized, due to the associationwith the Sertoli cells. When they reach maturity, they arereleased from the bundle and reach the locular lumen and theetferent ductule.DISCUSSIONThe unusual dark brown pigmentation of the testes ofPhysalaemus cuvieri is a peculiarity, which occur due to apresence of numerous pigmented cells (melano-macrophagesor typical melanocytes?) randomly distributed in the testicularcapsule and interstitium. This unusual characteristic, atesticular pigmentation, rarely is observed in others species,as described in Physalaemus fuscomaculatus (Aoki et aI.,1969) and Bombina bombina (Gollmann et aI., 1993). In theanuran Xenopus laevis, and other lower vertebrates, thepigment cells can be found in the different organs, constitutingan extracutaneous pigmentary system of unknown function(Zuasti et ai., 1998).Concerning the general histological architectureobserved in Physalaemus cuvieri, it was verified a greatsimilarity to the descriptions of the other species of samefamily, like Physalaemus fuscomaculatus (Aoki et aI.) andCaudiverbera caudiverbera (Hermosilla et aI., 1983); and alsowith species of the Hylidae family - Hyla ranki (Taboga &Dolder, 1991), Hyla japonica (Lee & Kwon, 1992); Hylapulchella andina (Montero & Pisanó, 1992); and Scinaxfuscovarius (Oliveira & Vicentini, 1998; Oliveira et al.). Inthe species that show a continuous spermatogenesis for ali thereproductive period, differerH cellular types may be identifiedin only one seminiferous locule, that is, ali the cells of thegerm lineage occupy the same locule and differentiatethemselves simultaneously.To Leptodactylids, Telmatobius laticeps andTelmatobius pisanoi (Montero & Pisanó, 1990), the histologicalarrangement is similar, however a potentially continuous cycleoccurs, considering that there is a well-defined phase of theintense spermatogenetic activity and other of rest, as it wasalso described to the hylidae: Hyla pulchella andina (Montero& Pisanó, 1992). In anurans like Nectophrynoides occidentalis(Zuber- Vogeli & Xavier, 1966), a temperate area bufonidae,the cycle is discontinuous, it influence even more in the gonadalactivity and consequently in the dynamic of spermatogenesis.For the neotropical area species, occurs preferentially acontinuous reproduction, in which ali the cellular types arepresent for whole year.With the cystic arrangement, the spermatogeneticlineage cells together with the Sertoli cells form delimitedgroups by a membranous capsule, which is denominated germcyst or spermatocyst. We stress the fact that independently ofthe reproductive cycle type of the species, the cysticarrangement of the germ cells is confirmed as an importantcharacteristic of the anuran amphibians, as well as to otheranamniotes vertebrates (Lofts; Grier et aI., 1980; Grier, 1992).In a similar way to what was obtained for Bufo woodhouse(Atherton, 1974), Caudiverbera caudiverbera (Hermosilla etai.) and Scinaxfuscovarius (Oliveira & Vicentini), we also donot observe any specific area of the testis where predominatecertain cellular kinds. It is corroborated by the apparentlyrandom distribution of the spermatocysts in the seminiferousstructures.Concerning the spermatogenetic lineage cells, the primordialspermatogonia are the biggest cells and rest on theadjacencies of the basallamina of the seminiferous structures,associated with the follicular cells (Lofts). As to the266
OLIVEIRA, C.; ZANETONI, C. & ZIERI, R. Morphological observations on the testes of Physalaemus cllvieri (Amphibia, Anura). Rev. Chi!o Allal., 20(3):263-268. 2002.spermatogonial types, similar observations to the Bufoarenarun (Cavicchia & Moviglia, 1983), Hyla ranki (Taboga& Dolder) and to the Scinaxfuscovarius (Oliveira et ai.) werealso verified in the species of this research.The spermatocytes generally are observed in theprophase of the first meiotic division, with different levels ofchromatinic and chromosomal condensation. Thespermatocytes l are commonly bigger than the spermatogoniaII (Lofts; Rastogi et ai. and Oliveira et ai.). With thespermatocytes l division, smaller cells are originated, thespermatocytes lI, which present half the diameter of the origincells, as we observed in the Physalaemus cuvieri.ln Caudiverbera caudiverbera (Hermosilla et ai.),Odontophrynus cultripes (Báo et ai., 1991), Scinaxfuscovarius(Oliveira et ai.) and in our analysis, the spermatids l, in a firststage, show a spherical nucleus and thin granulation, after thenuclei become oval and the granular chromatin is distributedhomogeneously. The following stages are characterized by acellular and nuclear elongation, which occur simultaneouslywith the chromatinic condensation, culminating with thespermatids II formation.At the end of the spermatogenesis, the spermatozoaremain united in the bundles, they are still sustained by theSertoli cells, however with their liberation to the lumen of theseminiferous locule, the arrangement is dissolved and theseremain in the spermatic path until the liberation.Although the architecture of the germ epithelium ofali mentioned species represents a general and typical modelfor the anurans, the final germ cell- the spermatozoon - showsa great heterogeneity in the species. This can be related tophylogenetic aspects (Kwon & Lee, 1995) and to reproductivestrategies of the anurans (Duellman & Trueb).ACKNOWLEDGMENTS : We are grateful to the CNPq forthe award of Scientific lnitiation Fellowship (PIBlC-CNPq96 to 98), to Cristiani Zanetoni, to Umberto Jorge Alves deAndrade for schematizing in translucent tracer paper, toRoberta Faria Femandes and Prof. Dr. Álvaro Luiz Hattnherfor the translation into English, to Profa. Dra. Rosa Maria daSilva and Dra. Roxana Guadalupe Herrera Álvarez fortranslation into castellano, and to Prof. Dr. Sebastião RobertoTaboga for the suggestions to the manuscript.OLIVEIRA, c.; ZANETONI, C. & ZIERI, R. Estudio morfológico de los testículos de Physalaemus cuvieri (Amphibia, Anura). Rev.Chi!oAnat., 20(3):263-268, 2002.RESUMEN: Generalmente, los testículos de anuros constituyen órganos ovoides, pares, formados por masa de estructurasseminíferas, envueltas en una capa de tejido conjuntivo fibroso, que contiene un epitelio germinativo provisto de tipos celulares característicos.En este trabajo se describe Ia anatomía y Ia arquitectura histológica de los testículos, así como también Ia organización ymorfología de Ias células germinativas. Se utilizaron cinco ejemplares machos de Ia especie Physalaemus cuvieri (Leptodactylidae),provenientes de Ia zona de Botucatu (São Paulo, Brasil). Tras el análisis macroscópico y Ia obtención de los fragmentos testiculares, elmaterial se sometió a Ias técnicas histológicas rutinarias para su inclusión en parafina y coloración con hematoxilina/eosina. Se constatócomo rara peculiaridad Ia presencia de numerosas células con pigmento distribuidas de forma aleatoria en Ia túnica albugínea e intersticiotesticular, Ias cuales otorgan ai testículo una coloración marrón oscura. En el tejido germinativo Ias espermatogonias I son Ias mayorescélulas espermatogenéticas. En Ia secuencia de Ia diferenciación y proliferación ce]ulares, se siguen ]os demás tipos de células(espermatogonias lI, espermatocitos I y lI, espermátidas I y lI, y espermatozoides) que presentan una organización cística, es decir,grupos de cé]ulas se asocian a ]as célu]as de Sertoli, formando ]os cistos espermatogenéticos o espermatocistos. Se diferenciaron eidentificaron Ias células dellinaje espermatogenético, según ]a morfología de ]as células y dei propio cisto.PALABRAS CLAVE: 1.Anura; 2. Leptodactylidae; 3. Physalaemus cuvieri, 4. Testículo; 5. Espermatogénesis.REFERENCESAoki, A.; Vitale-Calpe, R. & Pisano, A. The testicularinterstitial tissue of the amphibian Physalaemusfuscumaculatus. Z. Zellforsch. Mikrosk. Anat., 98:9-16, 1969.Atherton, R. W. A gradient analysis of spennatogenesis inthe toad Bufo woodhousei Girard (1854). Herpetologica,30:240-4, 1974.Báo, S. N.; Dalton, G. C. & Oliveira, S. F. Spermiogenesis inOdontophrynus cultripes (Amphibia, Anura, Leptodactylidae):ultrastructural and cytochemical studies ofproteins using E-PTA. 1. Morphol., 207:303-14, 1991.Cavicchia, 1. C. & Moviglia, G. A. The blood-testis barrier inthe toad (Bufo arenarum, HenseI): a freeze-fracture andlanthanum tracer study. Anat. Rec., 205:387-96, 1983.267
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Page 3: Figure 2. Detail 01'the histologica

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