No abstract

This study was conducted to explore the effect of energy substrates in the culture medium during in vitro maturation of bovine oocytes. A modified TCM199 medium (M-7528) was used to mature bovine oocytes in vitro. Oocytes were supplemented with different pyruvate (0.1, 0.2, 0.4 mM) and glucose (1.5, 5.6, 20.0 mM) concentrations for 48 hours at 38.5 °C under 5% CO2 atmosphere with 95% humidity. Their maturity was checked at 24 and 48 hours. After 48 hours, the denuded oocytes were stained with fluorescent dye JC-1 and avidin-FITC. Fluorescent dye JC-1 is a membrane permeable to the cell and would indicates membrane activity or its organization. Fluorescence intensity of avidin-FITC determination using corrected total cell fluorescence (CTCF) expressed oxidative stress level. There is a significant contribution of energy substrates towards oocyte maturation. Pyruvate at 0.2 mM produced mature oocytes with a diameter of ≥ 120 μm, promoted oocytes maturation to metaphase II (MII) stage faster and reduced cell’s oxidative stress levels. In comparison, 5.6 mM glucose is the optimum concentration for glucose to reduce cell stress level. Unfortunately, this concentration only produced mature oocytes with a small diameter of up to 116 μm. All changes were significant at the level of p < 0.05. As a conclusion, pyruvate at 0.2 mM is the optimum concentration for in vitro maturation after taking cell’s stress level into consideration.

There is no solid conclusion on the conventional sperm parameters in association with alcohol consumption, evaluation of sperm DNA integrity thus become a more reliable parameter. Hereby, this literature search was performed to summarize alcohol consumption on the sperm DNA integrity. A computerized database search was done through MEDLINE via Ovid (since 1946 until August 2017) and Cochrane was used. The following set of keywords: 'alcohol consumption OR alcohol intake OR alcohol diet OR drinking alcohol OR ethanol diet' AND 'sperm DNA OR sperm chromatin OR sperm genome OR sperm histone OR sperm protamine' were utilised. 24 articles were retrieved where only five studies conform to the inclusion criteria All studies demonstrated a negative effect of alcohol consumption on sperm DNA integrity, regardless of various range of alcohol doses and duration of alcohol consumption. Out of five studies reviewed, four studies were using a different approach to measure the sperm DNA damage. Hereby, this review identified a need to use a single approach of DNA damage test by having various method of alcohol administration and/or vice versa so that the extension of sperm DNA damage to alcohol consumption will have a better conclusion. On the same note, a few studies have reported the reversibility on conventional semen parameters, none has been done on the sperm DNA damage upon alcohol withdrawal. Therefore, the role of alcohol withdrawal on the reversibility of sperm DNA damage needs to be as well investigated further.