Effect of different vitrification protocols on post thaw viability and gene expression of ovine preantral follicles.

The aim of the present study was to establish a vitrification protocol for ovine preantral follicles, which can retain viability after thawing and to evaluate the impact of different vitrification treatments on apoptosis and development-related gene expression. Preantral follicles were isolated from cortical slices of ovaries by the mechanical method of isolation. The isolated preantral follicles (200-300 µm) were randomly assigned into four groups. Group1 - Control Fresh preantral follicles (256 follicles); Group 2- Vitrification treatment A (259 follicles) (Vitrification solution 1 (VS1) - Fetal bovine serum (FBS)10%, Ethylene glycol (EG):1.8 M, Dimethyl sulfoxide (DMSO): 1.4 M, Sucrose-0.3 M for 4 min; VS2- FBS10%, EG:4.5 M, DMSO: 3.5 M, Sucrose:0.3 M for 45 s), Group 3 - Vitr. treatment B (235 follicles) (VS1-FBS 20%, EG:1.3 M, DMSO1.05 M for 15 min, VS2- FBS 20%, EG:2.7 M, DMSO:2.1 M for 5 min) and Group 4-Vitrification treatment C (248 follicles) (VS1-Glycerol(Gly):1.2 M for 3 min, VS2- Gly:1.2 M, EG:3.6 M for 3 min, VS3- Gly3M, EG: 4.5 M for 1 min). Preantral follicles were placed in corresponding vitrification treatments and later plunged immediately into liquid nitrogen (-196 °C). After a week, the follicles were thawed and analyzed for follicular viability by trypan blue dye exclusion method as well as for gene expression. The results showed that the low concentration of cryoprotectants (vitrification treatment B) negatively affected the viability of preantral follicles in comparison with control follicles. There was no significant difference in the viability rates among the Control (87%), Treatment A (79%) and Treatment C (75%). The percentage of viable preantral follicles (73%) derived from Treatment B was significantly decreased (P<0.05%) in comparison to that of control. The expression of apoptotic gene BAK was higher in the vitrification treatment B group. Expressions of the other apoptosis-related genes i.e. Bcl2L1, BAD, BAX, Caspase 3, and Annexin showed no significant difference among the groups. The expression pattern of development competence genes GDF-9 and BMP-15 were higher (P < 0.05) in vitrification treatment A and C, respectively. Expression of NOBOX gene was significantly increased in preantral follicles with Vitrification treatment B compared to the control group. We conclude that both the Vitrification treatment A and Treatment C were the efficient vitrification treatment methods for the vitrification of ovine preantral follicles.

Effect of retinol as antioxidant on the post-thaw viability and the expression of apoptosis and developmental competence-related genes of vitrified preantral follicles in buffalo (Bubalus bubalis).

The present study evaluated the effect of supplementation of retinol in the vitrification solution on the viability, apoptosis and development-related gene expression in vitrified buffalo preantral follicles. Preantral follicles isolated from cortical slices of ovaries were randomly assigned into three groups: Group1-Control fresh preantral follicles; Group 2-Vitrification treatment (Vitrification solution 1 (VS1) -TCM-199 + 25 mM HEPES + Foetal bovine serum (FBS) 10%, Ethylene glycol (EG): 10%, Dimethyl sulphoxide (DMSO): 10%, Sucrose-0.3 M for 4 min; VS2- TCM-199 + 25 mM HEPES + FBS10%, EG:25%, DMSO: 25%, Sucrose:0.3 M for 45 s); Group3-vitrification treatment +5 µM of Retinol. Preantral follicles were placed in corresponding vitrification medium and plunged into liquid nitrogen (-196°C). After a week, the follicles were thawed and analysed for follicular viability and gene expression. There was no significant difference in the viability rates among the Group 1(Fresh preantral follicles) (91.46 ± 2.39%), Group 2 (89.59 ± 2.46%) and Group 3 (87.19 ± 4.05%). There was a significantly (p < .05) higher mRNA expression of BCL2L1, GDF-9 and BMP-15 in the vitrification + retinol group compared with the control group. There was a significantly (p < .05) higher expression of Caspase-3 and Annexin-5 in the vitrification group and Vitrification + retinol group compared with control group of follicles. It is concluded that the supplementation of 5 µM of Retinol in Vitrification solution was an efficient vitrification procedure for the vitrification of buffalo preantral follicles.

Disturbed spermatogenic signaling in pituitary adenylate cyclase activating polypeptide-deficient mice.

PACAP is a neuropeptide with diverse functions in various organs, including reproductive system. It is present in the testis in high concentrations, and in addition to the stage-specific expression within the seminiferous tubules, PACAP affects spermatogenesis and the functions of Leydig and Sertoli cells. Mice lacking endogenous PACAP show reduced fertility, but the possibility of abnormalities in spermatogenic signaling has not yet been investigated. Therefore, we performed a detailed morphological analysis of spermatozoa, sperm motility and investigated signaling pathways that play a role during spermatogenesis in knockout mice. No significant alterations were found in testicular morphology or motility of sperm in homozygous and heterozygous PACAP-deficient mice in spite of the moderately increased number of severely damaged sperms. However, we found robust changes in mRNA and/or protein expression of several factors that play an important role in spermatogenesis. Protein kinase A expression was markedly reduced, while downstream phospho-ERK and p38 were elevated in knockout animals. Expression of major transcription factors, such as Sox9 and phospho-Sox9, was decreased, while that of Sox10, as a redundant factor, was increased in PACAP-deficient mice. The reduced phospho-Sox9 expression was partly due to increased expression and activity of phosphatase PP2A in knockout mice. Targets of Sox transcription factors, such as collagen type IV, were reduced in knockout mice. In summary, our results show that lack of PACAP leads to disturbed signaling in spermatogenesis, which could be a factor responsible for reduced fertility in PACAP knockout mice, and further support the role of PACAP in reproduction.