Avicenna J Med Biotech arij002 Avicenna Journal of Medical Biotechnology 2008-2835 2008-4625 Avicenna Research Institute ajmb10382 Sericin Ameliorates the Capacitation State and Chromatin Integrity of Frozen-Thawed Stallion Spermatozoa by Reducing Oxidative Stress Heidari NasirabadiMahboobehShiraziAbolfazlReproductive Biotechnology Research Center, Avicenna Research Institute, ACECR , Tehran, IranKadivarAliMonoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, IranShams-EsfandabadiNaserMohebbiAbdolnaser AhmadiEbrahim 11 3 245 252 13 7 2018 9 8 2018

<p>Background: In the process of sperm cryopreservation, apart from cryoinjury, the production of Reactive Oxygen Species (ROS) can adversely affect the integrity of chromatin and cellular membranes. Addition of natural antioxidants to freezing me-dium is an approach to reduce the destructive effects of ROS on sperm.&nbsp;<br /> Methods: In this study, during 60 <em>min</em> of cooling process, the ejaculates of five stallions were diluted in the following media: INRA 82 medium as Control (C), INRA 82 medium supplemented with 0.25% Sericin (S), INRA 82 medium supplemented with 1.5 <em>mM</em> Glutathione (G), and INRA 82 medium supplemented with 0.25% Sericin+1.5 <em>mM</em> Glutathione (S+G).<br /> Results: In the frozen/thawed sericin supplemented group, while the integrity of DNA and the activity of catalase and Glutathione Peroxidase (GPx) were increased, the lipid peroxidation and midpieceab normality decreased, compared with other groups (p&lt;0.05). The proportions of sperms with abnormal head in group S and the sperm with distal droplet in G and S+G groups decreased, compared with group C (p&lt;0.05). In CTC assay, the percentage of capacitated spermatozoa in treatment groups was lower than control (p&lt;0.01).&nbsp;<br /> Conclusion: In conclusion, the presence of sericin in freezing medium of stallion semen could improve sperm DNA integrity and its resistance to ROS and lipid peroxidation.</p>