The Effect of Vitamin E and Poly Ethylene Glycol (PEG) Association on Chilled Rabbit Sperm: Impact on Sperm Motility and Oxidative Stress Status.

BACKGROUND: Vitamin E is the major lipid-soluble antioxidant, however, its potent effect is limited by its poor solubility. OBJECTIVE: The present study aimed to investigate whether polyethylene glycol 6000 (PEG) can enhance Vitamin E solubility and help protect sperm motility and against oxidative status. MATERIALS AND METHODS: Sperm groups consisted of the control aliquot diluted with Tris buffer and aliquots treated with Tris buffer containing polyethylene glycol (PEG), vitamin E (Vit E) or vitamin E- PEG complex (PEG/Vit E). Sperm motility was measured using a Computer Aided Semen Analysis at 0, 1, 3, 6 hours of cooling at 4°C. The oxidative stress status was measured at 4 hours using ABTS radical scavenging capacity. RESULTS: Sperm motility and oxidative status were significantly protected when using PEG and Vit E individually; however the most potent effects were observed in PEG/Vit E treatment. CONCLUSION: The present study demonstrated that treating rabbit semen with vitamin E complexed to PEG 6000 (PEG/Vit E) is effective in protecting sperm cells during chilling at 4°C.

Association of pregnancy per artificial insemination with gonadotropin-releasing hormone and human chorionic gonadotropin administered during the luteal phase after artificial insemination in dairy cows: A meta-analysis.

One strategy for improving fertility in cattle is administration of GnRH or human chorionic gonadotropin (hCG) during the luteal phase, which increases progesterone (P4) secretion and delays luteolysis. To provide an overview of how GnRH or hCG treatment between 4 and 15 d after artificial insemination (AI) improves pregnancy per AI (P/AI) in cows, a meta-analysis was performed on 107 different trials from 52 publications. Data from 18,082 treated cows and 18,385 untreated controls were meta-analyzed. The meta-analysis explained the relative risk for P/AI with GnRH or hCG treatment under various circumstances. The results did not show any difference in P/AI between cows treated with hCG and cows treated with GnRH. Compared with no treatment, treatment with GnRH or hCG improved the chances of P/AI in cows with very poor (<30%) and poor (30.1 to 45%) fertility, whereas treatment did not benefit cows with very good fertility (>60.1%). Moreover, treatment with GnRH and hCG improved the chances of P/AI in primiparous cows. The improvement was much better in primiparous cows with very low fertility. Treatment with buserelin at a dose above 10 µg and with hCG at a dose above 2,500 IU was associated with increased chances of P/AI compared with lower doses. Treatment with GnRH 10 d after AI was also associated with increased chances of P/AI compared with earlier treatment. The present meta-analysis showed that the use of GnRH and hCG after AI should be focused on cows expected to have low or moderate fertility. Day and dose of treatment have to be considered as well.

Effect of equilibration time on the motility and functional integrity of canine spermatozoa frozen in three different extenders.

The present work aimed to assess the effect of equilibration time on post-thaw motility parameters of canine sperm frozen in three extenders: 6% low-density lipoproteins (LDL), 6% liposomes (LIPO), and 40% egg yolk plasma (EYP). A second experiment is aimed at evaluating the functional integrity of canine spermatozoa frozen in the three extenders at the best equilibration time found in the experiment one. In the first experiment, 20 ejaculates harvested from 7 dogs, were frozen in three extenders (LDL, LIPO, and EYP) after four equilibration times (30min, 1h, 3h, and 6h). The semen was evaluated after thawing using an image analyser (HT-IVOS 14.0). The 6h equilibration time gave better results of motility and progressive motility in the three studied extenders. (LDL: 58.9% vs. 42.7%; LIPO: 54.4% vs. 31.9%; EYP: 55.4% vs 40.5% for motility 6 vs. 1h). In the second experiment, 10 ejaculates taken from 6 dogs were frozen under the same conditions as the previous experiment, after 6h equilibration time. The integrity parameters of the spermatozoal membrane (hypo-osmotic swelling test, and SYBR14/propidium Iodide staining), acrosome (FITC-Pisium sativum Aglutinin staining), and DNA (acridine orange staining) were evaluated at three different stages: post-dilution (T0), post-equilibration, and post-thawing. Post-thaw results were as follows: membrane integrity (HOSt: 62;6% vs 58% vs 64.4%; SYBR14/IP: 63.6% vs 57.9% vs 64.8%); acrosome integrity (FITC-PSA: 79.4% vs 74% vs 76.2%) and DNA integrity (Acridine-orange: 98.9% vs 98.5% vs 98.7%) respectively for LDL vs. LIPO vs. EYP. No significant difference existed between the extenders tested; thus 6%LIPO and 40%EYP could be good candidates for replacement of 6%LDL in the protection of canine sperm during the freeze-thaw process without altering motility and integrity parameters.

In-house preparation and evaluation of (125)I-histamine progesterone tracer for radioimmunoassay of progesterone.

The progesterone tracer for the development of in-house radioimmunoassay was prepared in two steps clearly described. First, activation of 11α-hemisuccinate progesterone (progesterone-11 α HS) and labeling of histamine with (125)I, and second, conjugation of activated 11α-HS progesterone with iodinated histamine. The purification of the tracer was carried out by gel filtration on Sephadex G-25. The radiochemical purity of purified the tracer was 95%. The maximum binding using solid phase (coated tubes) reached 41% and the non specific binding didn't exceed 5%. The tracer stored at different temperatures 10°C and -6°C was stable during 12 weeks. The skim milk provided assay better sensitivity (0.22 ng/mL) than serum (0.28 ng/mL).