Male reproductive cycle in a population of the endemic butterfly lizard, Leiolepis ocellata Peters, 1971 (Squamata: Agamidae) from northern Thailand

Background

Fundamental knowledge on the seasonal reproductive microanatomy and endocrinology of reptiles has been collected from several studies of various species. The present study was to determine annual changes in hormonal profiles, and detailed histomorphometric and histochemical characteristics of the entire male reproductive system of the tropical agamid lizard, Leiolepis ocellata.

Results

Male L. ocellata individuals (n = 75) collected from the territory of two provinces (Lampang and Tak) in northern Thailand exhibited annual variation in sex hormonal, histomorphometric, and histochemical characteristics of the male reproductive system. The reproductive cycle was subdivided into eight reproductive periods (early first active, first active, resting, second recrudescent, second active, regressive, quiescent, and first recrudescent), thus displaying a bimodal pattern with two actively reproductive periods. Circulating sex hormones (testosterone, estradiol, and progesterone) peaked in the first active (February) and the second active (June–July) periods. Likewise, gonadosomatic index (GSI) and histomorphometric variables of the testes and of the genital ducts (rete testis, ductuli efferentes, ductus epididymis, and ductus deferens) revealed their highest values in the first active period. Marked increase in protein and carbohydrate production was detectable in the ductuli efferentes during the active periods.

Conclusions

The male reproductive cycle of L. ocellata showed a biannual pattern of the hormonal profile, and detailed histomorphometric and histochemical characteristics of the entire reproductive system. Hence, the present study provides improved basic knowledge on the reptilian reproductive biology with comparative viewpoints to other reptiles.

Ontogeny of the testicular excurrent duct system of male Japanese quail (Coturnix japonica): A histological, ultrastructural, and histometric study

The testicular excurrent duct system undergoes several physiological and morphological changes during the reproductive stage or breeding season in mammals, birds, and reptiles. Studies on normal age-related histomorphological changes in the excurrent duct system of Japanese quails (Coturnix japonica) remain unreported, despite the extensive use of this bird as an avian model in research studies. The current study investigated the histological, ultrastructural, and histometric changes in the testicular excurrent duct system of the Japanese quail during three reproductive stages, namely prepubertal, pubertal, and adult. Simple squamous to low cuboidal cells formed the epithelia of the rete testis in prepubertal and pubertal birds, while in adult birds the lining was low cuboidal to cuboidal. In pubertal and adult birds, the nonciliated Type I epithelial cells of the proximal efferent duct displayed a subapical endocytotic apparatus comprising coated pits, coated apical tubules, and endosomes. There was a significant increase (p ≤ .001) in epithelial heights of all ducts of the excurrent duct system in the mature, sexually active, adult birds when compared to the other age groups. The luminal and tubular diameters, and the cross-sectional areas of efferent ducts and the epididymal duct unit increased significantly (p ≤ .001) with age. It is concluded that the morphology and morphometry of the excurrent ducts of the testis of the Japanese quail change as birds mature.

Gross and microanatomy of the male reproductive duct system of the saltwater crocodile Crocodylus porosus

Information on the morphology and histology of the male reproductive system of the Crocodylia species is necessary to determine the role of these tissues in the production of functional spermatozoa. Accordingly, in this study we examined the gross morphology and microanatomy of the testis and the male excurrent duct system through which spermatozoa pass before ejaculation. The data demonstrate that the reproductive system in male saltwater crocodiles comprises paired testes, which convey spermatozoa distally via the rete testis into an excurrent duct system comprising ductuli efferentes, ductuli epididymides, ductus epididymidis and ductus deferens. The epithelium delineating the male tract was dominated by non-ciliated and ciliated cells structured into a simple columnar lining of the ductuli efferentes and ductuli epididymides, through to the high pseudostratified columnar epithelium of the ductus epididymidis and ductus deferens. The morphology and histochemical staining of these ducts suggest their involvement in seminal fluid production and/or its modification, which likely contributes to the nourishment, protection and/or storage of crocodile spermatozoa. As a reflection of their common Archosaurs ancestry, the overall structural characteristics we describe for the crocodile male excurrent duct system share closer similarities to those of the Aves than other clades within the Reptilia class or Mammalia.

Morphology and biometry of the reproductive organs of adult males of Trachemys scripta elegans reared in São Paulo state, Brazil

ABSTRACT: Trachemys scripta elegans is an American underwater chelonian illegally marketed in Brazilian pet shops. When abandoned in nature, it compromises native species, threatening local biodiversity. However, little is known about the body development and structure of its reproductive tract. The objective of the present study was to investigate the morphology and biometry of testis, epididymis and penis, as well as the biometry of the body and secondary sexual characters in this species. Twenty-seven adult males were used aiming to contribute to preservation actions in captivity, population control, and scientific research, as well as to interspecific comparisons. Sex identification by the third claw length was effective, and the specimens presented harmonious and positive body development between mass, carapace, plastron, and height, with unimodal tendency and higher frequency of maximum carapace length at 15cm. The testes and epididymides presented biometric similarity between the antimeres and anatomical and histological structure similar to that of other species of chelonians and mammals, except for the type of epithelium. The findings suggest that there is conserved morphology between slider turtles and homology in relation to mammals. Histological similarity to the reproductive organs of other amniotes, including humans, may give rise to scientific and comparative studies, essential for the establishment of conservation strategies in reptiles.

Ultrastructure of epididymal epithelium and its interaction with the sperm in the soft-shelled turtle Pelodiscus sinensis

The epididymis of the soft-shelled turtle Pelodiscus sinensis was examined under light and transmission electron microscopes to determine the morphological characteristics, as well as their changes at different phases of the seasonal reproductive cycle. Three distinct regions, viz., cranial, middle and caudal were identified in the epididymis based on anatomical characteristics. The epididymal epithelium consists of five different cell types: principal, narrow, apical, clear and basal cells. Principal cells, which are the most abundant, together with basal cells are present along the entire length. Ultrastructural evidence suggests that all of the principal cells in each of the regions function in both absorption and secretion. Narrow cells and apical cells are rare and only confined to the cranial region. The clear cells, for the first time reported in the turtle epididymis, are confined to middle and caudal regions; these cells showed strong PAS-positive granulation in apical position, and secretory activity by a holocrine process, especially in the middle region. There was a significant difference in the epithelium height of all the regions between the reproductive season and the non-reproductive season. Sperm are stored in the epididymis throughout the year. Apart from the mature spermatozoa, immature spermatozoa with normal morphology are also observed. Under TEM, the immature spermatozoa showed a large amount of cytoplasm located eccentrically on the midpiece wrapped by plasma membrane, with some cytoplasm extended to the posterior of the head. Furthermore, the interactions of sperm with the epididymal epithelium were observed. Some sperm are associated with the secretory material in the lumen; other sperm are inserted into the intercellular space between the epithelial cells.

Green Brazilian propolis effects on sperm count and epididymis morphology and oxidative stress

Basal generation of reactive oxygen species (ROS) is essential for male reproductive function, whereas high ROS levels may be linked to low quality of sperm and male infertility. The number of antioxidants known to inflict damage is growing, and it will be of interest to study natural products, which may have this activity. Since the epididymis is known to play an important role in providing the microenvironment for sperm maturation and storage of sperm, this study was undertaken to evaluate the morphometric-stereological and functional alterations in the epididymis after chronic treatment with low doses of Brazilian green propolis, which is known for its antioxidant properties. For this purpose, forty-eight adult male Wistar rats were treated with 3, 6 and 10 mg/kg/day of aqueous extract of Brazilian green propolis during 56 days and morphological parameters, sperm production and number of sperm in rat epididymis and oxidative stress levels were analyzed. The results showed higher sperm production and greater epithelium height of the epididymis initial segment and no induction of oxidative stress in treated animals. Further studies are needed to fully understand the effects of propolis on the reproductive system but our results showed that it could alter male reproductive function.