Isolamento e criopreservação de folículos ovarianos pré-antrais de marrãs pré-púberes

Abstract

The aim of this study it was to isolate mechanically and cryopreserve ovarian follicles from pre pubertal gilts; with glycerol on the concentrations of 1,5 M and 3 M. Eighteen ovaries from pre pubertal gilts were used (n = 18) sectioned using tissue chopper in sections with interval of 250 e 500 μm. The follicular quantifying was performed in neubauer chamber and the viability analysis in microscope. In the section of 250 μm the mean number of isolated follicles was 168.889 ± 69.017, while on the section of 500 μm the mean number was 180.000 ± 92.800, being in both sections the mean number of preantral follicles were statistically similar. The rate of follicular viability was 76,50% and 74,08% in the sections of 250 and 500 μm, respectively, not showing significant difference. In the second study were used twelve (n=12) ovaries from pre pubertal gilts processed mechanically in tissue chopper, making sections of 250 μm. Designed to the toxicity test, glycerol was added on the final concentration of 1,5 e 3 M. The rate of viability of preantral follicles on the control group without glycerol 72,72 %, after exposition to glycerol 1,5 M (tox- 1,5) and 3 M (tox-3) was 62,15% and 12,07%, respectively, being that there was no statistical difference between the control without glycerol and the tox-1,5 and there was between control without glycerol and tox-3 and between tox-1,5 and tox-3. After the cryopreservation/thawing procedure the number of viable preantral follicles was 18,88% on the glycerol group 1,5 M (cryo-1,5) and 2,81% on the group glycerol 3M (cryo-3) did not show statistical difference. At cryo-1,5 and cryo-3 the rates of viability in relation to the control group without glycerol (72,72%) showed significantly different and low, and between cryo-1,5 and cryo-3 were not significant. The analysis of viability from the test of toxicity and cryopreservation/thawing with glycerol, on the concentration of 1,5 M (tox-1,5 and cryo1,5) was significantly lower in cryo 1,5, while at the same analysis on the concentration of 3 M (tox-3 and cryo-3) there was no difference. In conclusion, both interval of section (250 and 500 μm) can be used on the isolation of ovarian follicles from pre pubertal gilts with the same efficiency and after the exposition to glycerol 1,5 M showed the best viability rate, however in both concentrations 1,5 e 3 M the cryopreservation was not satisfactory.