Effect of Spermine-NONOate on acrosome reaction and associated protein tyrosine phosphorylation in Murrah buffalo (Bubalus bubalis) spermatozoa

Acute exposure to organophosphorus pesticide metabolites compromises buffalo sperm function and impairs fertility

Agrichemicals such as organophosphorus pesticides' metabolites (OPPMs) are more hazardous and pervasive than their parent pesticides. Parental germline exposure to such xenobiotics leads to an elevated susceptibility towards reproductive failures e.g. sub- or in-fertility. This study sought to examine the effects of low-dose, acute OPPM exposure on mammalian sperm function using buffalo as the model organism. The buffalo spermatozoa were briefly (2 h) exposed to metabolites of the three most prevalent organophosphorus pesticides (OPPs) viz. Omethoate (from Dimethoate), paraoxon-methyl (from methyl/ethyl parathion) and 3, 5, 6-trichloro-2-pyridinol (from chlorpyrifos). Exposure to OPPMs resulted in compromised structural and functional integrity (dose-dependent) of the buffalo spermatozoa typified by elevated membrane damage, increased lipid peroxidation, precocious capacitation and tyrosine phosphorylation, perturbed mitochondrial activity and function and (P < 0.05). This led to a decline in the in vitro fertilizing ability (P < 0.01) of the exposed spermatozoa, as indicated by reduced cleavage and blastocyst formation rates. Preliminary data indicate that acute exposure to OPPMs, akin to their parent pesticides, induces biomolecular and physiological changes in spermatozoa that compromise their health and function ultimately affecting their fertility. This is the first study demonstrating the in vitro spermatotoxic effects of multiple OPPMs on male gamete functional integrity.

A systematic review and meta-analysis of spermatozoa cryopreservation, in vitro and in vivo fertility practices in water buffalo

We explored different aspects of buffalo spermatozoa during cryopreservation. The meta-data comprised of 285 studies, published from January 2008 to March 2020. A free web tool CADIMA as well as PRISMA 2009 Flow Diagram were used for carrying out this study. The inter-reviewer agreement among studies allocated was satisfactory for criteria A (selection bias), B (performance bias), C (detection bias) and D (attrition bias), respectively. India led the percent (%) research ladder with 34.4, followed by Pakistan (29.5), Egypt (12.3), Iran (7.7), Italy (5.6), Indonesia (3.2), China (2.1), Brazil (1.4), Thailand (1.1), Philippines and Bulgaria (0.7 each), Saudi Arabia, Turkey, Vietnam, and USA (0.4 each). Among four categories of studies, Group-1 evaluated only supplements/additives/media in the freezing semen extender (n = 191/285; 67.02%); Group-2 conducted in vivo fertilization (n = 62/285; 21.75%) and Group-3 conducted in vitro fertilization/ cleavage rate/penetration rate/ blastocyst yields (n = 28/285; 9.82%) with their specific cryodiluents/media, respectively. Group-4 conducted different experimental supplements/additives/media and carried out both in vitro and in vivo fertilization simultaneously (n = 4/285; 1.40%). Conventional spermatozoa cryopreservation was reported by 51.9% studies followed by programmable fast freezing by 20.7% studies. A few leading extender types included BioXcell (3.9%); Soyamilk-skim (3.5%); and Andromed (2.1%). The study also describes French straws for semen filling, cooling temperatures, extension time, equilibration time, cryopreservation stages, thawing temperatures, seasons, thawing time, and stains used during semen evaluation assays. The study concludes that the research on spermatozoa cryopreservation of buffalo is largely conducted at quality level and a need of applying these findings for evaluation of fertility potential (in vivo and in vitro) is indispensable for effective genetic improvement.

Silk protein sericin pretreatment enhances osmotic tolerance and post-thaw sperm quality but reduces the ability of sperm cells to undergo in vitro induced acrosome reaction in rabbit

Effect of sericin pretreatment of sperm cells on the osmotic tolerance, ability to undergo acrosome reaction induced by calcium ionophore (CI), heparin (H) or lysophosphatidylcholine (LPC), post-thaw sperm quality and in vivo fertility was evaluated in four successive experiments in rabbit. In experiment 1, fresh semen was pretreated with sericin (0, 0.1% or 0.5% w/v) before exposing to fructose solutions adjusted to either 50, 100, 290, 500 or 1000 mOsm/L. Sericin pretreatment increased sperm livability in addition to live-membrane intact and total membrane intact sperm rates (P < 0.05) in 50 and 290 mOsm/L groups. In experiment 2, sperm samples were pretreated by either 0.1 or 0.5% sericin after removal of the semen plasma. CI, H or LPC were used to induce acrosome reaction in pretreated sperm samples. Sericin pretreatment, reduced the ability of sperm cells to undergo acrosome reaction (P < 0.05) in vitro. In experiment 3, ejaculates were frozen with or without sericin pretreatment in DMSO-sucrose extender. In post-thaw samples sericin pretreatment improved total and progressive motility, livability, membrane and acrosome integrity in a dose dependent manner (P < 0.05). In vivo fertility trials by artificial inseminations revealed contradictory results in experiment 4. Although 0.5% sericin pretreatment totally inhibited fertility, 0.1% sericin provided high pregnancy rates. In conclusion; sericin pretreatment enhances osmotic tolerance and post-thaw sperm quality, but reduces the ability of rabbit sperm cells to undergo in vitro induced acrosome reaction, but this effect is restored in vivo by dose dependent manner.

Regulation of boar sperm functionality by the nitric oxide synthase/nitric oxide system

Purpose

Nitric oxide (NO) is a free radical synthesized mainly by nitric oxide synthases (NOSs). NO regulates many aspects in sperm physiology in different species. However, in vitro studies investigating NOS distribution, and how NO influences sperm capacitation and fertilization (IVF) in porcine, have been lacking. Therefore, our study aimed to clarify these aspects.

Methods

Two main experiments were conducted: (i) boar spermatozoa were capacitated in the presence/absence of S-nitrosoglutathione (GSNO), a NO donor, and two NOS inhibitors, N^G-nitro-L-arginine methyl ester hydrochloride (L-NAME) and aminoguanidine hemisulfate salt (AG), and (ii) IVF was performed in the presence or not of these supplements, but neither the oocytes nor the sperm were previously incubated in the supplemented media.

Results

Our results suggest that NOS distribution could be connected to pathways which lead to capacitation. Treatments showed significant differences after 30 min of incubation, compared to time zero in almost all motility parameters (P < 0.05). When NOSs were inhibited, three protein kinase A (PKA) substrates (~ 75, ~ 55, and ~50 kDa) showed lower phosphorylation levels between treatments (P < 0.05). No differences were observed in total tyrosine phosphorylation levels evaluated by Western blotting nor in situ. The percentage of acrosome-reacted sperm and phosphatidylserine translocation was significantly lower with L-NAME. Both inhibitors reduced sperm intracellular calcium concentration and IVF parameters, but L-NAME impaired sperm ability to penetrate denuded oocytes.

Conclusions

These findings point out to the importance of both sperm and cumulus-oocyte-derived NO in the IVF outcome in porcine.

Electronic supplementary material

The online version of this article (10.1007/s10815-019-01526-6) contains supplementary material, which is available to authorized users.