Viability of vitrified bovine preantral follicles in plastic straws

Abstract

This study aimed to verify the viability of pre-antral follicles after vitrification in plastic straw. The ovaries were collected in a slaughterhouse and transported to the laboratory where they were isolated. The liquid containing the isolated follicles were divided into three groups: control group (G1), analyzed immediately, without vitrification, group toxicity (G2), only exposed to the cryoprotectants; group vitrified (G3), filled in plastic straws (0.25 mL) and imersed in liquid nitrogen. The cryoprotectants used to test for toxicity and the vitrification was a solution composed of ethylene glycol by 20 % and 20 % of dimethylsulfoxide in 0.5 M sucrose. In devitrification follicles were transferred to a solution of sucrose at 0.25 M, and then to a solution of sucrose at 0.15 M. The preantral follicles were classified as nonviable/viable when they were stained/not stained with trypan blue, respectively. The G1 (261/280, 93.2 %) showed significant differences with G2 and G3 (p<0.05) and the G2 (141/221; 66,3 %) showed difference (p<0.05) with the G3 (76/300, 25.3 %). The results indicate that support the plastic used was not efficient in preservation of pre-antral follicles cattle in the process of vitrification. Keywords: Vitrification, preantral follicles, ovarie, cattle.