The aim of this study was to determine the effect of butylated hydroxytoluene (BHT) supplemented cryopreservation medium on sperm parameters during the freeze-thaw process. In addition, sperm lipid peroxidation, DNA damage, and the amount of reactive oxygen species (ROS) were determined. Semen samples were obtained from 75 donors. Fifteen semen samples were used for optimizing BHT concentration and incubation time and 60 samples were used for the final experiments. After the determination of basic parameters, groups of three sample with similar parameters were pooled and processed by Pure Sperm gradient centrifugation. The semen samples were then diluted with normal freezing medium (control) or a medium containing 0.5 mM BHT (test) for 5 minute and stored in liquid nitrogen. Frozen cryovials were thawed individually for 20 seconds in a water bath (37°C) for evaluation. Freezing extenders supplemented with 0.5 mM BHT led to higher sperm motility and viability compared with control samples (p < 0.001). Furthermore, the addition of BHT decreased malondialdehyde (MDA) formation, DNA fragmentation, and ROS content compared with controls (p < 0.001). Our results showed that the addition of BHT to the freezing medium could be of advantage in reducing ROS and preventing the detrimental effect of ROS on the human sperm function.

Background: Ammonia, urea, uric acid, and creatinine are the major non-protein nitrogenous compounds (NPNs). It is reported that the concentration of NPNs in the seminal plasma of normal and infertile individuals is different and sperm is affected by NPNs. Objectives: The aim of this study was to determine the quantities of ammonia, urea, uric acid, and creatinine in seminal plasma and the correlation of these compounds with the fertilization rate after an intracytoplasmic sperm injection (ICSI). Methods: The levels of ammonia, urea, uric acid, and creatinine were determined in seminal plasma collected from 50 men. The ammonia and urea were determined by L-glutamate dehydrogenase and diacetyl monoxime method, respectively. Uric acid and creatinine were detected by enzymatic method and Jaffe reaction, respectively. The fertilization was evaluated around 16–18 hours post-ICSI on the appearance of 2 pronuclei and 2 polar bodies. The fertilization rate was calculated by the number of fertilized oocytes per the number of oocytes injected. Results: There was a significant negative correlation between seminal ammonia and sperm motility (P<0.05). Urea and creatinine had a negative correlation with respect to the sperm count (P<0.05). In addition, there was an inverse correlation between urea and uric acid of seminal plasma and sperm morphology (P<0.05). A significant negative correlation was found between seminal uric acid and urea with respect to the percentage of the fertilization rate (P<0.05). Conclusions: The findings of the present study showed that urea and uric acid in seminal plasma have a negative impact on the fertilization rate.

This study reports the isolation of two mucoid strains of H. pylori with confluent growth under aerobic and microaerobic conditions. It appears that production of exopolysaccharide (EXP) could serve as a physical barrier to reduce oxygen diffusion into the bacterial cell and uptake of antibiotics. EXP protected the mucoid H. pylori isolates against stressful conditions, the result of which could be persistence of bacterial infection in the stomach.