Identification and isolation of sprmatogonial stem cells from beluga ( Huso huso) testicular tissue

Spermatogonial stem cells (SSCs) are unique cells and able to transmit genetic information to the next generation, therefore, they play an important role in chimeric fish production and preservation of rare species. This study was performed for the first time with the aim of examining morphology of spermatogonial cells through histological method and then isolating them through enzymatic digestion method from beluga (Huso huso) testicular tissue. Histological examination of testicular tissue of one- to three-year-old beluga showed there are two general types of spermatogonial cells, undifferentiated spermatogonia (SSCs) and differentiated spermatogonia. SSCs were often identified by their large size, irregular nuclear envelope, distinct nuclear components and one to two nuclei. Moreover, in one-year-old fish the frequency of SSCs was significantly higher than 2 and 3-year-old beluga (P<0.05). Isolation of testicular tissue cells of one-year-old beluga through enzymatic digestion was indicated that using 0.1% trypsin enzyme with phosphate buffer for 2 to 3 hours at 16-20°C has higher efficiency based on frequency and viability of beluga spermatogonial cells (P<0.05). This study has provided basic information for isolation beluga SSCs for transplantation to produce chimeric fish.