Assessment of the cryoprotective effects of fetal bovine serum (FBS) and trehalose on the viability rate of caprine spermatogonial stem cells (SSCs)

Spermatogonial stem cells (SSCs) are the foundation of spermatogenesis, because they have the capacity of self-renewal, and differentiation into spermatozoa. Freezing is the most common long-term preservation approach for SSCs. The present study aimed to investigate the cryoprotective impacts of FBS (Fetal Bovine Serum) and trehalose on caprine SSCs.

SSCs were isolated from prepubertal goat testis by enzymatic digestion and differential plating. Cells were divided into 9 groups. The control group included SSCs without cryoprotective agents. In the treatment groups 1, 2, 3 and 4, concentration of 10% FBS, and various concentrations of trehalose (0, 50, 100 and 200 mM), and in the treatment groups 5, 6, 7, and 8, concentration of 20% FBS and various concentrations of trehalose (0, 50, 100 and 200 mM) were used respectively. The viability rate of the cells was assessed immediately after isolation, following addition of cryoprotectant agents and after thawing. Identification of cells was confirmed by immunocytochemical staining against PGP9.5 antigen. Data were analyzed using one-way ANOVA test.

The viability rate of SSCs in various treatments following addition of FBS and trehalose were similar to viable cells immediately after isolation. Furthermore, higher viability rates of SSCs after thawing were observed in freezing medium containing 10% FBS and 200 mM trehalose (P<0.05).

The results revealed that freezing in 10% FBS with 200 mM trehalose acts as efficient method for the cryopreservation of caprine SSCs.