Efficiency of using inositol in cryoprotective media for freezing tissues of postembryonic gonads of female Gallus gallus domecticus

Purpose : The aim of the study was to determine the efficiency of the freezing protocol for day-old chick ovaries depending on the composition of the cryoprotective medium. Materials and Methods . Russian Snow White chickens (n=30) were used to obtain the ovaries of day-old chicks. Freezing was performed using a simple two-stage vitrification method, using DPBS-based cryoprotective media containing dimethyl sulfoxide, ethylene glycol, and sucrose as cryoprotectants in the control (medium A) and the addition of inositol (0.5 M) (medium B) in an experimental modification of the cryoprotective medium. The effectiveness was assessed after in vitro storage at -196°C for 30 days, based on the condition of primary follicles in histological samples. Results . Data were obtained based on the results of evaluating histological samples for the integrity of oogonia in the cortex of thawed ovaries: when using cryoprotective medium A, the number of morphologically intact oogonia was 1,4 pcs. per field of view (magnification x400), which was 5,4 % of the indicator for native samples; when using medium B — 9,0 pcs. oogonia (34,5 % of native). Conclusion. The creation of a long-term cryobank for the storage of female gametes of the avian class (Aves) is a relevant strategic solution to the problem of preserving the genetic diversity of breeds and species. The efficiency of gonadal tissue freezing depends on the chosen donor age and the cryopreservation protocol, taking into account the composition of the cryoprotective media. The presented data prove the effectiveness of the protocol for freezing the ovaries of day-old chicks using a cryoprotective medium containing inositol (medium B) allows preserving a significant percentage of morphologically intact ovarian tissue structures and, directly, the oogonia in it.