Inhibin-A and Inhibin-B in stallions: Seasonal changes and changes after down-regulation of the hypothalamic-pituitary-gonadal axis

Oral vaccination with inhibin DNA vaccine for promoting spermatogenesis in rats

The objective of the present study was to evaluate the effects of a novel Inhibin (INH) DNA vaccine (C500/pVAX-asd-IS) on the immune response, reproductive hormone levels, and spermatogenesis of rats. Forty healthy male rats were divided into four groups, and respectively immunized (thrice, 14 d apart) with 1×108, 1×109, and 1×1010 CFU of the recombinant inhibin vaccine (group C500/pVAX-asd-IS-L, C500/pVAX-asd-IS-M, and C500/pVAX-asd-IS-H) or 1×1010 CFU C500. P/N values increased after vaccination and differed (p <0.05) at 7 d, and sharply increased at 14 d following the booster vaccination (p <0.01); The weight and volume of testes in C500/pVAX-asd-IS groups were increased (p < 0.05) at decapitation, respectively; Histological evaluation showed that the number of spermatogenic cells in the lumen was increased, and the cytoplasmic remnants of sperms were allergy increased significantly compared with the control group. Oral vaccination with INH DNA reduced (P < 0.05) serum concentrations of INH B, enhanced serum concentrations of testosterone (T) and FSH. Furthermore, mRNA expressions of VIM and SMAD4 in the testes were increased in C500/pVAX-asd-IS-M and C500/pVAX-asd-IS-H groups (p < 0.05 or p < 0.01). The mRNA amount of INHβ-B in C500/pVAX-asd-IS-M group was greater than control group (p < 0.05).These results suggested that neutralization of endogenous INH through oral vaccination with INH DNA delivered by C500 strain successfully elicited a humoral immune response. INH gene immunization may have a positive effect on spermatogenesis and reproductive efficiency in male rats.

A Prepubertal Mice Model to Study the Growth Pattern of Early Ovarian Follicles

Early folliculogenesis begins with the activation of the follicle and ends with the formation of the follicular antrum, which takes up most of the time of folliculogenesis. In this long process, follicles complete a series of developmental events, including but not limited to granulosa cell (GC) proliferation, theca folliculi formation, and antrum formation. However, the logical or temporal sequence of these events is not entirely clear. This study demonstrated in a mouse model that completion of early folliculogenesis required a minimum of two weeks. The oocyte reached its largest size in the Type 4-5 stage, which was therefore considered as the optimum period for studying oogenesis. Postnatal days (PD) 10-12 were regarded as the crucial stage of theca folliculi formation, as Lhcgr sharply increased during this stage. PD13-15 was the rapid growth period of early follicles, which was characterized by rapid cell proliferation, the sudden emergence of the antrum, and increased Fshr expression. The ovarian morphology remained stable during PD15-21, but antrum follicles accumulated gradually. Atresia occurred at all stages, with the lowest rate in Type 3 follicles and no differences among early Type 4-6 follicles. The earliest vaginal opening was observed at PD24, almost immediately after the first growing follicular wave. Therefore, the period of PD22-23 could be considered as a suitable period for studying puberty initiation. This study objectively revealed the pattern of early folliculogenesis and provided time windows for the study of biological events in this process.

Equine granulosa cell tumours among other ovarian conditions: Diagnostic challenges

BACKGROUND

Granulosa cell tumours (GCT) are the most common ovarian tumours in mares. While the classical presentation may not represent diagnostic challenges, diagnosis is not easy in the early stages.

OBJECTIVES

Illustrate the variability in the presentation and serum biomarkers associated with ovarian abnormalities in the mare.

STUDY DESIGN

Retrospective case series.

METHODS

Nonclassical cases of GCTs and other ovarian conditions were identified and behaviour, GCT endocrine results, palpation and ultrasonographic findings are described and the diagnostic value of each is discussed.

RESULTS

Mares in this case series with GCTs had been presenting clinical signs ranging from no behavioural changes to behaviours including aggression, stallion-like and inability to work under saddle. Hormonal profiles of endocrinologically functional GCTs can be erratic and unpredictable. The clinical form and ultrasonographic appearance may also vary with time from an initially enlarged/anovulatory follicular structure that later develops a multicystic 'honeycomb' appearance. Mares with GCTs can also present with persistent anovulatory follicles or apparent luteal tissue that are unresponsive to treatment. If both ovaries are of relatively normal size and symmetry, but hormonal biomarkers are markedly increased (AMH >10 ng/mL, inhibin B and/or testosterone >100 pg/mL; 0.37 nmol/L), it is likely that a functional GCT is present. Still, it can be a challenge to decide which ovary to remove. Post-surgical endocrine testing can be helpful, especially if histopathology is not performed or a GCT is not found.

MAIN LIMITATIONS

Cases limited to 14.

CONCLUSIONS

Granulosa cell tumours present with a wide variety of clinical signs that do not fit what is commonly described as 'classic'. Only if AMH, testosterone and inhibin B concentrations are markedly increased, and there is an abnormally enlarged ovary, the diagnosis of a GCT is more confident. In the presence of normal size ovaries, normal hormonal biomarkers and abnormal behaviour, it is more likely that the ovaries are not involved.

Semen quality and freezability analysis during breeding and non-breeding seasons in heavy draft stallions in southern Chile

The aim of this study was to evaluate seasonal changes in basic parameters of sperm quality and freezability behaviour of ejaculates from 10 fertile heavy draft stallions. A total of 140 ejaculates were collected, processed and evaluated during both the breeding (September-November) and non-breeding seasons (April-June). Fresh semen was evaluated for volume, concentration, total spermatozoa per ejaculate, plasma membrane integrity and total sperm motility. Cryopreserved samples were evaluated for plasma membrane integrity and sperm motility by the CASA system, and for the freezability index (FI), which was defined as the decreased ratio of viability after freezing-thawing. In fresh ejaculates, only viability showed significantly higher values in the breeding than in the non-breeding season (64.0% ± 15.0% vs. 58.6% ± 12.0%, respectively; p < .05). The sperm post-thawing analysis of viability and total motility parameters showed no significant changes linked to the season. However, the FI analysis showed that the ejaculates collected in the non-breeding season had higher cryoresistance characteristics than those collected in the breeding season. Results suggest that the presence of some cryoprotective factor/s in heavy draft horse ejaculates could be modulated by seasonality, with higher protective effects in the non-breeding season.