Sperm Invitro Research Articles

Bicarbonate and BSA increase the capacitation pattern and acrosomal exocytosis in boar sperm after 120 min of incubation.

Sperm capacitation is a crucial step towards the acquisition of fertilizing capacity. Despite the attempts to mimic the invivo situation, there is still a lack of standardization invitro techniques. Bicarbonate and serum albumin (BSA) are routinely used, although controversial results are reported regarding the optimal concentration of each compound. In addition, whether caffeine is needed on invitro capacitation media in boar sperm remains to be elucidated. Here, 18 boar commercial artificial insemination doses were used to test different concentrations of bicarbonate (19, 37 or 56 mM) in experiment 1, BSA (1.5, 3, 4.5 mg/mL) in experiment 2 and the presence or absence of caffeine (5.15 mM) experiment 3. We analysed at 0, 30 and 120 min of incubation at 38.5°C, 5% CO2 : Total motility (TMOT), membrane integrity (VIAB), acrosomal exocytosis (rAcro; H33342/PI/PNA), capacitation status (chlortetracycline staining CTC) and mitochondrial membrane potential (JC-1). The higher concentrations of bicarbonate (37 and 56 mM) decreased TM and VIAB (p < .01) but increased rAcro (p < .01) after 120 min of incubation compared to the fresh control. In contrast, only the BSA concentration of 3 mg/mL reduced the VIAB at 120 min, but all the concentrations tested increased the average of JC-1 and decreased TM (p < .01) throughout incubation compared to the fresh control. Finally, in experiment 3, when boar sperm were incubated in the capacitating media with bicarbonate, BSA and with or without caffeine, the capacitated pattern measured by the CTC technique and rAcro increased after 120 min of incubation (p < .01) compared to fresh control, either in the presence or in the absence of caffeine. In summary, our results suggested that the combination of capacitating components, like bicarbonate and BSA, contributed to increasing the proportion of capacitated boar spermatozoa, mitochondrial membrane potential as well as acrosomal exocytosis. However, caffeine did not significantly influence invitro sperm capacitation in this species.

A Study On the Effect of Citrulline Concentrations On In-Vitro Sperm Motility in Diabetic Infertile Male

A Study On the Effect of Citrulline Concentrations On In-Vitro Sperm Motility in Diabetic Infertile Male

103 Characterization of the receptors of the endocannabinoid system in equine sperm: Possible role of anandamide in sperm function

Conventional IVF in horses remains challenging. In particular, stallion sperm fails to penetrate the zona pellucida, possibly due to incomplete invitro sperm capacitation. Therefore, there is a need to elucidate, in horses, molecules with a proven role during capacitation in other mammals. Our laboratory has described the relevance of the endocannabinoid system in capacitation of bovine and murine sperm. We reported that anandamide (AEA), an endocannabinoid present in follicular and oviducal fluids, induced capacitation-associated events. The aims of this work were to characterise the localization of cannabinoid receptors in equine sperm and to evaluate the effects of AEA on levels of tyrosine-phosphorylated proteins (pY) and substrates phosphorylated by protein kinase A (pPKA). Both cannabinoid receptors (CB1, CB2, TRPV1) and pPKA and pY were localised in sperm by indirect immunofluorescence. Sperm (15×106mL−1) were incubated, at 38.5°C in air, in modified Tyrode’s-albumin-lactate-pyruvate (TALP) with 25mM NaHCO3, 5mM dextrose and 1mgmL−1 polyvinyl alcohol (PVA; TALP-Bic-PVA) or TALP-Bic-PVA supplemented with AEA (0.1, 1, 10, 100nM, and 1µM) for 4h. After incubation, Western blot was used to determine levels of pY and pPKA in 4.5×106 sperm. Cryopreserved sperm samples from three stallions were evaluated. The normality of data distributions and homoscedasticity were verified with the Shapiro-Wilk and Levene tests, respectively. Data were analysed by one-way ANOVA and Bonferroni post hoc test, with P&amp;lt;0.05 considered significant. Based on immunofluorescence, CB1 was mainly localised in the post-acrosomal region and flagellum (93.4%±5.5, mean±s.d.), CB2 in the post-acrosomal region and middle piece (89.9%±28.3), and TRPV1 in the post-acrosomal region and flagellum (89.3%±9). Sperm positive for pPKA had fluorescence in the middle piece and principal piece of the flagellum. Incubation with 1nM AEA for 4h induced a 61% increase in pPKA levels compared with TALP-Bic-PVA medium alone, with no induction of pY levels in any treatment. In conclusion, cannabinoid receptors were present in equine sperm, and incubation with AEA induced an increase in PKA activity, an essential event associated with sperm capacitation. To our knowledge, this was the first report describing the presence of receptors of the endocannabinoid system in equine sperm and the potential role of AEA in the acquisition of sperm fertilizing ability.

A competitive environment influences sperm production, but not testes tissue composition, in house mice.

Due to the physiological cost of sperm production, males are expected to be prudent in their expenditure and adjust their investment according to current social conditions. Strategic adjustments in sperm expenditure during development can be made via changes in testes size, sperm production rates or testes tissue composition. Here, using house mice, we test the hypothesis that elevated sperm production is driven by a plastic response in the spatial organization of the testes. We reared males under different social conditions (competitive vs. noncompetitive) and quantified sperm number and the proportion of sperm-producing tissue within the testes. Further, because sperm quality is a critical determinant of competitive fertilization success, we used computer-assisted sperm analysis to quantify six sperm motility traits. Our investigation revealed that males reared in an environment with a perceived risk of reproductive competition produced more sperm in the absence of changes in testes morphology. We discuss this result in relation to fixed and flexible phenotypically plastic responses to future competitive conditions, and conclude that adaptive adjustments in sperm number in response to the social environment are likely attributable to variation in sperm production rate. Further, we found no difference in invitro sperm motility parameters among males from the different social environment regimes. Overall, this investigation improves our understanding of the mechanisms of male plasticresponses to reproductive competition experienced during sexual development.

Effects of supplementation of iodixanol to semen extender on quality and fertilization ability of frozen-thawed Thai native bull sperm.

This study investigates the effects of iodixanol supplementation in varied concentrations to Tris egg yolk (TEY) extender on the quality and fertilization ability of frozen-thawed sperm of Thai native bulls. Each ejaculate was divided into four different groups, as follows: sperm were treated with TEY extender (control group) and TEY extender supplemented with three different concentrations of iodixanol (1.25%, 2.50% and 5.00%). Semen straws were frozen in liquid nitrogen vapor. After thawing, sperm motility characteristics, viability, plasma membrane integrity and acrosome integrity were determined. Also, frozen-thawed spermatozoa from all groups were used for invitro fertilization and artificial insemination (AI) in natural estrus Thai native cows. The results showed that the post-thaw quality of the 2.50% iodixanol group was superior to the other iodixanol groups (P<0.05). However, iodixanol had no beneficial effect on post-thaw sperm invitro fertilization ability and pregnancy rate after AI (P>0.05). It can be concluded that the supplementation of 2.50% iodixanol extender significantly improves the progressive motility, viability, plasma membrane integrity and acrosome integrity of cryopreserved semen from Thai native bulls, but it has no beneficial effect on invitro fertilization ability and pregnancy rate after AI.

A Review of New Technologies that may Become Useful for in vitro Production of Boar Sperm.

Making sperm cells outside the original testicular environment in a culture dish has been considered for a long time as impossible due to the very complicated process of spermatogenesis and sperm maturation, which altogether, encompasses a 2-month period. However, new approaches in complex three-dimensional co-cell cultures, micro-perfusion and micro-fluidics technologies, new knowledge in the functioning, culturing and differentiation of spermatogonial stem cells (SSC) and their precursor cells have revolutionized this field. Furthermore, the use of better molecular markers as well as stimulatory factors has led to successful invitro culture of stem cells either derived from germ line stem cells, from induced pluripotent stem cells (iPSC) or from embryonic stem cells (ESC). These stem cells when placed into small seminiferous tubule fragments are able to become SSC. The SSC beyond self-renewal can also be induced into haploid sperm-like cells under invitro conditions. In mouse, this invitro produced sperm can be injected into a mature oocyte and allow post-fertilization development into an early embryo invitro. After transferring such obtained embryos into the uterus of a recipient mouse, they can further develop into healthy offspring. Recently, a similar approach has been performed with combining selected cells from testicular cell suspensions followed by a complete invitro culture of seminiferous cords producing sperm-like cells. However, most of the techniques developed are laborious, time-consuming and have low efficiency, placing questionable that it will become useful used for setting up an efficient invitro sperm production system for the boar. The benefits and drawbacks as well as the likeliness of invitro pig sperm production to become applied in assisted technologies for swine reproduction are critically discussed. In this contribution, also the process of sperm production in the testis and sperm maturation is reviewed.

Improvement in sperm motility viability and normality after treatment with prednisolone antisperm antibody separation and in invitro sperm activaition in immunologyically infertile men

improvement in sperm motility viability and normality after treatment with prednisolone antisperm antibody separation and in invitro sperm activaition in immunologyically infertile men

Human cervical mucus: Research update

Evaluation of cervical mucus is a standard for determining the fertile period in natural family planning. Cervical mucus accepts, filters, prepares, and releases sperm for successful transport to the egg and fertilization. Recent scientific advances provide answers to how the mucus regulates fertility as its physical properties change during the menstrual cycle. Transmission electron microscopy reveals small interstices between mucus macromolecules relative to a sperm head. Thus advancing sperm must push aside or cut through the microstructure. The interstices are largest in the periovulatory phase of the cycle. Small magnetic spheres, comparable with the size of a sperm head, are now being used to study the physical properties of the mucus on the scale of individual sperm.