Immuno-histological mapping and functional association of seminal proteins in testis and excurrent ducts with sperm function in buffalo.

The region-specific expression of seminal proteins in testis and excurrent duct system determines the quality and function of the spermatozoa. In the present study, localization and expression of some of the seminal proteins such as insulin-like growth factor receptor 1ß (IGF-1Rß), phosphatidylethanolamine-binding protein 4 (PEBP4), α-tubulin and tissue factor pathway inhibitor 2 (TFPI2) were carried out in testis, excurrent duct system and spermatozoa of buffalo. IGF-1Rß was localized in the cells of the seminiferous tubules of the testis, except in primary spermatocytes. The PEBP4 was localized only in the elongated spermatid, whereas α-tubulin and TFPI2 proteins were localized in all cells of the seminiferous tubule including spermatocyte. In the buffalo spermatozoa, IGF-1Rß, PEBP4, α-tubulin and TFPI2 were localized in the acrosome region, the post-acrosomal region till the tail end, post-acrosome to the entire tail region and the equatorial region, respectively. The study indicates that IGF-1R, α-tubulin and PEBP4 proteins regulate spermatogenesis, whereas TFPI2 may be involved during the zona binding process of the buffalo spermatozoa.

Isolation and enrichment of putative spermatogonial stem cells from ram (Ovis aries) testis.

The present study aimed to isolate and enrich putative SSCs from ram testes, which are positive for promyelocytic leukaemia zinc-finger protein (PLZF). The putative SSCs were isolated using a combination of enzymes with different concentrations, collagenase (1 and 2 mg/ml), hyaluronidase (1 mg/ml) and trypsin (0.25 and 0.5 mg/ml). The isolated SSCs were purified using an extracellular matrix such as laminin (20 µg/ml), DSA-lectin (5 µg/ml) and gelatin (0.2%) in combination with BSA (0.5 mg/ml). The number of putative SSCs/ tubule was significantly (p < 0.05) higher in prepubertal (3.1 ±â€¯0.51) and adult (3.45 ±â€¯0.58) than the number of gonocytes/tubule in neonatal (0.59 ±â€¯0.03) testis. Optimum enzyme combinations required for isolation of putative SSCs from prepubertal testis (collagenase; 2 mg/ml and trypsin; 0.5 mg/ml) were different from adult testis (collagenase; 1 mg/ml, trypsin; 0.25 mg/ml and hyaluronidase; 1 mg/ml). Though the number of putative SSCs/tubule was comparable in prepubertal and adult animals, a significantly (p < 0.05) higher percentage of putative SSCs (7.33 Vs 0.47%) were isolated from prepubertal testis than the adult. Differential plating using laminin along with BSA resulted in a significantly (p < 0.05) higher number of putative SSCs. The enzyme combinations suitable for isolation of putative SSCs from prepubertal testis are different from adult ram testis and the laminin has been found to be effective for purification of putative SSCs from testicular cells isolates.

Current status of sperm functional genomics and its diagnostic potential of fertility in bovine (Bos taurus).

With artificial insemination (AI) and other precision dependent assisted reproductive technologies (ART) being followed in large scale in human and animal reproduction, assessing semen quality and fertilizability is under continuous scrutiny. Various tests have been developed to predict semen quality, but so far no single, highly reliable test is available. In this regard, transcriptomic profiling of spermatozoa assumes significance as it carries the information about spermatogenesis, sperm function, and paternal roles in post-fertilization events. Human spermatozoal transcriptome profiling has been carried out on a large number of individuals to predict the semen quality. A study in human indicated that the outcome of some idiopathic couples seeking reproductive care could be helped using transcriptomic profiling of spermatozoa. Such studies have a direct impact on the bovine dairy industry, wherein AI is practiced. Limited studies in bovine spermatozoal transcriptome profiling have revealed that the spermatozoa contain various classes of RNA, like in human. Approximately 13,000 bovine genes yield a series of spermatozoal transcripts, of which most are fragmented in nature. Their abundance is indicative of the timing of events associated with spermatogenesis, e.g., PRM1, IGF1, BMP2; sperm function, TSSK6, CRISP, HSFY2; fertility, UBE2D3, Integrin-ß, LDC-1; and embryonic development, miR34c-5p, BCL2L11, BRCA1. The most abundant translated bovine transcripts are BSP3 and SPATA18, and are involved in regulation of germ cell development and the maintenance of chromatin integrity during spermatogenesis respectively. The presence of transcripts associated with placental development, e.g., placental associated glycoproteins (PAGs) have suggested their possible influence beyond early embryonic development. Changes in transcript levels like RPL31 and PRKCE that increase, and PRM1 that decreases, during cryopreservation need to be defined in order to optimize cryopreservation and fertility yield. Spermatozoal transcriptome profiling with validation studies are warranted in large numbers of animals to elucidate their significance for selecting fertile bulls for the breeding program. Abbreviations: AI: artificial insemination; BSE: breeding soundness evaluation; cfs-mRNA: cell-free seminal mRNA; piRNA: PIWI-interacting RNA; tRNA: transfer RNA; fg: femtogram; TPM: transcripts per million reads; RPKM: reads per kilobase million; rRNA: ribosomal RNA; mt-RNA: mitochondrial RNA; lncRNA: long non-coding RNA; sncRNA: small noncoding RNA; snoRNA: small nucleolar RNA; snRNA: small nuclear RNA; miRNA: microRNA; snaR: small NF90-associated RNAs; SINES: short interspersed nuclear elements; LINES: long interspersed nuclear elements; MER: medium reiterated sequence; F1 offspring: filial 1 offspring; PAGs: placental associated glycoproteins; TCP: Transcription factor T complex protein; BSP3: bovine seminal plasma protein 3; SCNT: somatic cell nuclear transfer; qPCR: quantitative (real-time) polymerase chain reaction; SSH: suppression subtractive hybridization; SNP: single nucleotide polymorphism; 2-DE: 2 dimensional gel electrophoresis; LC-MS/MS: liquid chromatography-tandem mass spectrometry.

Cryoprotective role of organic Zn and Cu supplementation in goats (Capra hircus) diet.

The current study focused on cryopreservation and assessment of characters of post-thaw semen of indigenous Osmanabadi bucks maintained with standard diet, supplemented with different concentrations of organic zinc (Zn), copper (Cu) or in combination, for a period of 180 days. The different doses of organic Zn and Cu were fed per kg DM basis, Zn groups (low: Zn20, medium: Zn40 and high: Zn60), Cu groups: (low: Cu12.5, medium: Cu25 and high: Cu37.5) and combination of Zn + Cu groups (low: Zn20 + Cu12.5, medium: Zn40 + Cu25 and high: Zn60 + Cu37.5) respectively. The control group bucks were maintained mainly on the basal diet without any additional mineral supplementation. Two hundred and forty (240) semen samples were collected from 40 bucks aged 11 months, through electro ejaculator method, processed and analysed for sperm quality parameters both at pre freeze and post-thaw stage. The semen samples were diluted in Tris egg yolk extender, cooled and equilibrated for 4 h at 5 °C, cryopreserved using programmable freezer (PLANER Kryo 360-1.7) and stored at -196 °C. The organic trace minerals (Zn, Cu and Zn + Cu) protected the spermatozoa against the cryoinjury and maintained higher post-thaw semen parameters except in high Zn group. Additional feeding of organic Cu and Zn to bucks had a protective role and resulted in higher sperm liveability, plasma membrane and acrosome integrities, motility and velocity and reduced oxidative stress in supplemented goats (P < 0.05).

Novel insights into the role of cell-free seminal mRNAs on semen quality and cryotolerance of spermatozoa in bulls (Bos taurus).

The aim of the present study was to ascertain the effectiveness of seminal plasma mRNAs as markers to assess the reproductive performance of bulls. Semen samples (33 ejaculates) from 11 bulls were evaluated for sperm kinematic and functional parameters. Total RNA was isolated from cell-free seminal (cfs) using TRIzol LS reagent and the concentration of cfs-RNA was 24.4±2.3µgmL-1 seminal plasma. The cfs-RNA was fragmented to a size of 25-500bp. Of the cfs-mRNAs screened using real time PCR, expression of protamine 1 (PRM1) was positively (P<0.05) associated with the mitochondrial membrane potential of raw semen, whereas expression of Fas Ligand (FASLG) was negatively (P<0.05) associated with sperm velocity, membrane integrity and chromatin distribution in post-thaw semen samples. The percentage of Type A spermatozoa (amplitude of lateral movement of head >2.5µm and straightness >85%) in raw semen was positively (P<0.05) associated with bone morphogenetic protein 2 (BMP2), ubiquitin conjugating enzyme E2D3 (UBE2D3), tumour-associated necrotic factor-associated death domain (TRADD) and caspase-3 (CASP3) expression. Nerve growth factor (NGF) expression was positively (P<0.05) associated with the maintenance of post-thaw functional membrane integrity in spermatozoa and could be used to assess the cryotolerance of bull semen. In conclusion, the expression of cfs mRNAs can be used to assess the reproductive performance of males and to predict the sensitivity of spermatozoa to cryoinjury.

Occurrence and functional significance of the transcriptome in bovine (Bos taurus) spermatozoa.

Mammalian spermatozoa deliver various classes of RNAs to the oocyte during fertilization, and many of them may regulate fertility. The objective of the present study was to determine the composition and abundance of spermatozoal transcripts in fresh bull semen. The entire transcriptome of the spermatozoa from bulls (n = 3) was sequenced using two different platforms (Ion Proton and Illumina) to identify the maximum number of genes present in the spermatozoa. The bovine spermatozoa contained transcripts for 13,833 genes (transcripts per million, TPM > 10). Both intact and fragmented transcripts were found. These spermatozoal transcripts were associated with various stages of spermatogenesis, spermatozoal function, fertilization, and embryo development. The presence of intact transcripts of pregnancy-associated glycoproteins (PAGs) in the spermatozoa suggest a possible influence of sperm transcripts beyond early embryonic development. The specific regions (exon, intron, and exon-intron) of the particular spermatozoal transcripts might help regulate fertilization. This study demonstrates that the use of two different RNA-seq platforms provides a comprehensive profile of bovine spermatozoal RNA. Spermatozoal RNA profiling may be useful as a non-invasive method to delineate possible causes of male infertility and to predict fertility in a manner that is more effective than the conventional methods.

IGF1 stabilizes sperm membrane proteins to reduce cryoinjury and maintain post-thaw sperm motility in buffalo (Bubalus bubalis) spermatozoa.

Insulin like growth factor 1 (IGF1) in the seminal plasma is reported to improve sperm motility by reducing oxidative stress. The present study was conducted to assess the effect of addition of IGF1 on sperm function and protein composition during cryopreservation process. Semen samples were collected from six Murrah buffaloes (2 ejaculates from each animal) and diluted (80 million/ml) in tris egg yolk extender and divided into control, T1, T2 and T3, groups supplemented with 0, 50, 100 and 150 ng of IGF1/mL, respectively. The semen was filled in straws (250 µL) and straws from each group were divided into two batches. One batch was processed for freezing and another batch was incubated at 4 °C for 4 h. The sperm kinematic and functional parameters were studied in both the batches. A significant (P < 0.05) positive effect of IGF1 was observed on functional membrane integrity (%) during incubation at 4 °C for 4 h in T3 as compared to control group. The spermatozoa (%) positive for structural membrane integrity, mitochondrial membrane potential and the metabolic activity in post-thaw semen were significantly (P < 0.05) high in T3 than the control group. The acrosomal integrity was significantly (P < 0.05) higher in T2 group as compared to control. The proteins (kDa) of 17.3 with pI 4.2 (calmodulin), 11.3 with pI 6.5 (dermcidin) and 18.1 with pI 5.5 (sperm acrosome membrane associated protein3) were protected in IGF1 group. The study suggests that IGF1 can be added to the extender for improving cryosurvial of buffalo spermatozoa.