بررسي اثر استرس گرمايي بر پارامترهاي اسپرمي و نسبت جنسي اسپرم هاي حاوي كروموزوم X يا Y پس از انجماد – ذوب سيمن بز

The effect of heat stress on sperm parameters and sex ratio of Y or X- bearing spermatozoa after goat semen cryopreservation

اﻧﺘﺨﺎب ﺟﻨﺴﯿﺖ ﻗﺒﻞ از ﻟﻘﺎح ﻓﺮآﯾﻨﺪي اﺳﺖ ﮐﻪ ﻃﯽ آن از اﺳﭙﺮﻣﻬﺎي ﺗﻌﯿﯿﻦ ﺟﻨﺴﯿﺖ ﺷﺪه ﺣﺎوي ﮐﺮوﻣﻮزوم X ﯾﺎ Y اﺳﺘﻔﺎده ﻣﯿﺸﻮد ﺗﺎ ﺟﻨﺴﯿﺖ دﻟﺨﻮاه در زاده ﻫﺎ ﺗﻮﻟﯿﺪ ﺷﻮد. اﻋﺘﻘﺎد ﺑﺮ اﯾﻦ اﺳﺖ ﮐﻪ اﺳﭙﺮم ﻫﺎي ﺣﺎوي ﮐﺮوﻣﻮزوم X در ﻣﻘﺎﯾﺴﻪ ﺑﺎ اﺳﭙﺮم ﻫﺎي ﺣﺎوي Y داراي ﻃﻮل ﻋﻤﺮ ﺑﯿﺸﺘﺮ ﺑﻮده و در ﺷﺮاﯾﻂ اﺳﯿﺪي، ﺗﻐﯿﯿﺮات دﻣﺎﯾﯽ و ﺣﺘﯽ اﺳﺘﺮس اﮐﺴﯿﺪاﺗﯿﻮ ﻣﻘﺎوم ﺗﺮ ﻣﯽ ﺑﺎﺷﻨﺪ. ﻫﺪف از اﻧﺠﺎم ﺗﺤﻘﯿﻖ ﺣﺎﺿﺮ ﺑﺮرﺳﯽ اﺛﺮ اﺳﺘﺮس ﮔﺮﻣﺎﯾﯽ ﺑﺮ ﭘﺎراﻣﺘﺮﻫﺎي اﺳﭙﺮﻣﯽ و ﻧﺴﺒﺖ ﺟﻨﺴﯽ اﺳﭙﺮم ﻫﺎي ﺣﺎوي ﮐﺮوﻣﻮزوم X ﯾﺎ Y ﭘﺲ از اﻧﺠﻤﺎد – ذوب ﺳﯿﻤﻦ ﺑﺰ ﺑﻮد. ﺳﯿﻤﻦ رﻗﯿﻖ ﺷﺪه ﮔﺮوه اﺳﺘﺮس ﮔﺮﻣﺎﯾﯽ، اﺑﺘﺪا ﺑﻪ ﻣﺪت 30 دﻗﯿﻘﻪ در دﻣﺎيC43 ﻗﺮار داده ﺷﺪ و ﺳﭙﺲ ﻫﻤﺎﻧﻨﺪ ﮔﺮوه ﮐﻨﺘﺮل ﻣﻨﺠﻤﺪ-ذوب ﺷﺪﻧﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ اﺳﺘﺮس ﮔﺮﻣﺎﯾﯽ ﻣﻨﺠﺮ ﺑﻪ ﮐﺎﻫﺶ ﻣﻌﻨﯽ دار ﭘﺎراﻣﺘﺮ ﺗﺤﺮك ﮐﻠﯽ اﺳﭙﺮم، زﻧﺪه ﻣﺎﻧﯽ و ﯾﮑﭙﺎرﭼﮕﯽ ﻏﺸﺎ ﺳﻠﻮﻟﯽ اﺳﭙﺮم در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﮔﺮوه ﮐﻨﺘﺮل ﺷﺪ. ﻫﻤﺠﻨﯿﻦ در ﮔﺮوه اﺳﺘﺮس ﮔﺮﻣﺎﯾﯽ ﻣﯿﺎﻧﮕﯿﻦ ﻧﺴﺒﺖ Y ﺑﻪ X ﺑﻪ ﻣﯿﺰان 94/4 درﺻﺪ ﺑﻮد ﮐﻪ در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﻣﯿﺎﻧﮕﯿﻦ Y ﺑﻪ X ﺑﻪ ﻣﯿﺰان 1 ﻣﻮرد اﻧﺘﻈﺎر، ﺗﻔﺎوت ﻣﻌﻨﯽ داري )001/p< ( ﻧﺸﺎن داد. اﻋﻤﺎل اﺳﺘﺮس ﮔﺮﻣﺎﯾﯽ ﺑﻪ اﺳﭙﺮم در ﺷﺮاﯾﻂ آزﻣﺎﯾﺸﮕﺎﻫﯽ ﻣﯽ ﺗﻮاﻧﺪ ﻣﻨﺠﺮ ﺑﻪ ﮐﺎﻫﺶ ﻣﻌﻨﯽ دار ﭘﺎراﻣﺘﺮﻫﺎي اﺳﭙﺮﻣﯽ ﺷﻮد ﺑﻪ ﻋﻼوه ﮐﺎﻫﺶ ﺗﻌﺪاد اﺳﭙﺮم ﻫﺎي ﺣﺎوي ﮐﺮوﻣﻮزوم Y در ﻣﻘﺎﯾﺴﻪ ﺑﺎ X در ﺟﻤﻌﯿﺖ زﻧﺪه ﻣﺎﻧﺪه ﭘﺲ از اﻧﺠﻤﺎد-ذوب، ﻣﯽ ﺗﻮاﻧﺪ ﻧﺸﺎن دﻫﻨﺪه ﺣﺴﺎس ﺗﺮ و ﺷﮑﻨﻨﺪه ﺗﺮ ﺑﻮدن اﺳﭙﺮم ﻫﺎي ﺣﺎوي ﮐﺮوﻣﻮزوم Y در ﻣﻘﺎﯾﺴﻪ ﺑﺎ اﺳﭙﺮم ﻫﺎي ﺣﺎوي X در ﮔﻮﻧﻪ ﺑﺰ ﺑﺎﺷﻨﺪ.

Pre-sex selection is the process by which Y or X-bearing spermatozoa are used to produce the desired sex in the offspring. X-bearing spermatozoa are believed to have a longer lifespan, and are more resistant to acidic conditions, temperature changes, and even oxidative stress compared to Y-bearing. Methods : The present study was aimed to investigate the effect of heat stress on sperm parameters and sex ratio of sperm containing X or Y chromosome after freezing-thawing of goat semen. The diluted semen of the heat stress group was first placed at 43 ° C for 30 minutes and then frozen-thawed as in the control group. Results : The results showed that heat stress led to a significant reduction in the overall sperm motility, viability and sperm cell membrane integrity compared to the control group. Also, in the heat stress group, the mean Y to X ratio was 94.4%, which showed a significant difference (p <001) compared to the expected Y to X ratio of 1. Conclusion : Applying heat stress to sperm in vitro can lead to a significant reduction in sperm parameters. In addition, the decrease in the number of Y-bearing spermatozoa in the survived population post thawing, may indicate that the Y-bearing spermatozoa are more sensitive and fragile compared to X-bearing spermatozoa in goat species.