RT - Journal Article T1 - The Relation between Intracellular Calcium Concentration and Reactive Oxygen Species Production in Fresh and Cryopreserved-Thawed Human Spermatozoa JF - yums-armaghan YR - 2021 JO - yums-armaghan VO - 26 IS - 5 UR - http://armaghanj.yums.ac.ir/article-1-3137-en.html SP - 729 EP - 743 K1 - Human spermatozoa K1 - Cryopreservation K1 - Intracellular calcium K1 - Reactive oxygen species K1 - Cryoinjury AB - Background & aim: Storing frozen sperm in liquid nitrogen is a widely used method of preserving them for a long time. Many of these sperms are not damaged or survive after thawing, and many lose their motility. These injuries are caused by damage to the sperm membrane and changes in permeability to ions due to changes in osmotic pressure, the formation of ice crystals, and increased production of oxygen free radicals. The aim of the present study was to determine the relationship between intracellular calcium concentration and the production of oxygen free radicals in fresh and frozen human-thawed spermatozoa. Methods: In this quasi-experimental study conducted in 2013, 35 samples of fertile human cement were randomly selected and divided into two groups: fresh and frozen-thawed. The sperm of the frozen-thawed group were preserved under liquid nitrogen for one month. The effect of 10 µM calcium ionophore A23187 was evaluated on fresh and thawed sperm motility, viability, and acrosome reaction. Oxygen free radical production and intracellular calcium content were evaluated using luminol and Flou-3/AM staining by chemiluminescence and flowcytometric method, respectively. Data were compared using the Mann–Whitney test. P<0.05 was considered statistically significant. Results: The percentage of alive, motile and progressive sperm and the percentage of sperm with intact acrosome decreased significantly after the freezing-thawing process. The addition of A23187 to the medium increased intracellular calcium in live sperm but decreased the percentage of live and motile sperm in both groups. The production of free radicals increased per live cell in both groups, but this increase was significantly higher in the frozen-thawed group than in the fresh group. The results indicated a significant positive relationship between intracellular calcium and the production of oxygen free radicals. Conclusion: Calcium ions were required for normal sperm function, but increased calcium entry by A23187 into fresh or frozen-thawed sperm causes more damage and reduced motility and survival. The amount of oxygen free radicals had a direct and significant relationship with intracellular calcium. Freezing damage was exacerbated by higher levels of intracellular calcium, which may be due to increased production of oxygen free radicals. LA eng UL http://armaghanj.yums.ac.ir/article-1-3137-en.html M3 10.52547/armaghanj.26.5.729 ER -