The ABCA1 blocking agent probucol decreases capacitation in ejaculated dog spermatozoa

Molecular Biomarkers of Canine Reproductive Functions

The aim of the current study is to review potential molecular biomarker substances selected so far as useful for assessing the quality of dog semen. Proteins, lipids, carbohydrates, and ions can serve as molecular biomarkers of reproductive functions (BRFs) for evaluating male reproductive health and identifying potential risk factors for infertility or reproductive disorders. Evaluation of BRF levels in semen samples or reproductive tissues may provide insights into the underlying causes of infertility, such as impaired sperm function, abnormal sperm-egg interaction, or dysfunction of the male reproductive tract. Molecular biomarker proteins may be divided into two groups: proteins that are well-studied, such as A-kinase anchoring proteins (AKAPs), albumins (ALBs), alkaline phosphatase (ALPL), clusterin (CLU), canine prostate-specific esterase (CPSE), cysteine-rich secretory protein 2 (CRISP2), lactotransferrin (LTF), metalloproteinases (MMPs), and osteopontin (OPN) and proteins that are not well-studied. Non-protein markers include lipid-based substances (fatty acids, phosphatidylcholine), carbohydrates (glycosaminoglycans), and ions (zinc, calcium). Assessing the levels of BRFs in semen samples may provide valuable information for breeding management and reproductive assessments in dogs. This review systematizes current knowledge that could serve as a starting point for developing practical tests with the use of biomarkers of canine reproductive functions and their predictive value for assisted reproductive technique outcomes and semen preservation.

First study on molecular epidemiology of caseous lymphadenitis in slaughtered sheep and goats in Duhok Province, Iraq

Background

Caseous lymphadenitis (CLA) is a chronic suppurative bacterial infection caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis) affecting superficial and internal lymph nodes and internal organs of small ruminants.

Aims

Through the use of molecular methods, this study aimed to estimate the prevalence of CLA and its contributing factors as well as the degree of genetic diversity and epidemiological relationships among C. pseudotuberculosis isolates from slaughtered sheep and goats in various districts of Duhok Province, Iraq.

Methods

A total of 18,836 carcasses (15,775 sheep and 3,061 goats) were inspected by veterinarians at slaughterhouses [Duhok-Sumel (2,453 sheep + 627 goats), Zakho (6,000 sheep), Bardarash (1,117 sheep + 379 goats), Amedi (413 sheep + 178 goats) and Akre (5,792 sheep + 1,877 goats)] in Duhok Province for detection the prevalence rate of CLA using molecular techniques.

Results

The prevalence of the disease was 0.94% and 1.93% in sheep and goats, respectively. Sheep in Duhok-Sumel and goats in Amedi were at a higher risk of infection than the animals in another location, with a prevalence rate of 4.31% and 6.18%, respectively. Sheep and goats of older age were more susceptible. Females were more susceptible than males in all districts except Duhok-Sumel where the reverse was true. ERIC-PCR analysis grouped the bacterial isolates into 11 different genotypes. The maximum likelihood phylogenetic tree of partial sequences of the 16S rRNA gene sequences of C. pseudotuberculosis revealed no divergent sequences discovered in this study.

Conclusion

A strict control program needs to be applied to reduce the entrance of pathogen from neighboring countries.

Inhibition of the cholesterol transporter ABCA1 by probucol decreases capacitation and tyrosine phosphorylation of dog spermatozoa, and is dose dependent

The ATP binding cassette (ABC) transporter molecule ABCA1 participates in the cholesterol transport within and through cell membranes. We recently demonstrated that in dog spermatozoa, capacitation could be decreased with probucol (PRO), an ABCA1 specific antagonist. In this study, a dose-effect relationship of PRO on dog sperm capacitation, tyrosine phosphorylation and cholesterol efflux from the sperm plasma membrane was investigated. A total of 16 ejaculates from dogs of different breeds, aged 2-4 years were used. Sperm motility and membrane integrity in the main fraction was determined by CASA. Samples were stained with a boron dipyrromethene difluoride (BODIPY) fluorophore (P9672, Sigma- Aldrich, A) diluted in DMSO at a final concentration of 0.4 μM. All samples were divided into 5 aliquots, with 0, 100, 250, 500 and 1000 μM of PRO. After incubation at 37 °C for 2 h, PI was added and flow cytometry performed. All aliquots were examined for capacitation and acrosome reaction by using the CTC assay and tyrosine phosphorylation (TP). Membrane integrity was measured in all aliquots to investigate the effect of PRO on cell membranes. Membrane integrity did not differ between controls (0 μM), and 100, 250 and 500 μM PRO, but decreased with 1000 μM PRO (p < 0.05). Increasing PRO concentration decreased the percentage alive cells with cholesterol efflux per PRO group (0 μM: 77.8 ± 10.6%, 100 μM: 63.7 ± 11.7%, 250 μM: 52.1 ± 12.9%, 500 μM: 37.7 ± 11.6%, 1000 μM: 33.1 ± 14.4%; p < 0.05), decreased head and entire tail phosphorylated cells (0 μM: 34.6%, 1000 μM: 5.1% p < 0.05); and decreased the percentage capacitated cells (maximum with PRO 500 μM: capacitated vs. control: 54.2 ± 17% vs 25 ± 7.7%, p < 0.05). Conclusion: PRO decreased the cholesterol efflux, and decreased tyrosine phosphorylation and capacitation in a dose-dependent manner. This suggests a strong involvement of the ABCA1 transporter in different functional aspects of sperm capacitation in dogs.

Using egg yolk in a TRIS-Equex STM paste extender for freezing of dog semen is superior to egg yolk plasma, also after addition of lecithin and catalase

We compared the results of using egg yolk plasma (EYP) instead of egg yolk (EY) in a TRIS-based Equex STM Paste freezing extender system for dog semen [25]. We also tested whether the addition of lecithin and catalase to the EYP extenders would improve results. Fractionated semen collection was done in 17 stud dogs and the sperm rich fraction diluted with different extenders in 2 steps: (I) TRIS-fructose-citric acid extender (TRIS) containing 20% egg yolk (EY) and 3% glycerol [25], (II) TRIS containing 20% egg yolk plasma (EYP) and 3% glycerol, and (III) TRIS containing 20% EYP and 0.8% lecithin (EYP-L) and 3% glycerol. After equilibration the second dilution step was done: samples with (I) were diluted with TRIS-EY with 7% glycerol and 1% Equex STM paste [25]; samples with (II) and (III) were divided in 2 aliquots each, and one part diluted with TRIS-EYP or TRIS-EYP-L, both containing 7% glycerol and 1% Equex STM paste, and the other one part with the same extenders containing additionally 300 I.U./mL catalase. After freezing and thawing, samples were analyzed by CASA and sperm chromatin structure assay (SCSA); reactive oxygen species (ROS), degree of apoptosis and zona binding ability were determined. Semen samples with TRIS-EY with a final concentration of 5% glycerol and 0.5% Equex STM paste [25] showed best post thaw progressive motility (P), most intact cells, lowest percentage of ROS, acrosome damages, dead and apoptotic cells. Curvilinear velocity (VCL), DNA fragmentation, morphological abnormalities and zona binding ability did not differ between groups. Replacement of egg yolk by EYP increased the ROS and late apoptotic cells. Addition of lecithin and catalase to EYP containing extenders decreased motility and increased complete apoptosis. We conclude that egg yolk is superior to EYP in the here investigated extenders. The TRIS-based extender [25] with EYP could not be improved by addition of lecithin and catalase; however, in-vivo fertilization capacity of the here examined extenders remains to be investigated.