Teste de toxicidade e criopreservação de folículos pré-antrais ovinos isolados utilizando Glicerol, Etilenoglicol, Dimetilsulfóxido e Propanodiol / Toxicity test and cryopreservation of sheep isolated preantral follicles using glycerol, ethylen glycol, dimethil sulfoxyde and propanediol

O objetivo deste estudo foi avaliar foliculos pré-antrais (FOPA) ovinos isolados após sua exposição e criopreservação utilizando glicerol (GLI), etilenoglicol (EG), propanodiol (PROH) ou dimetilsulfóxido (DMSO) a 1,5 e 3,0 M. Cada par ovariano de 5 ovelhas sem raça definida foi coletado em abatedouro local e submetido ao isolamento folicular. Da suspensão obtida, uma aliquota foi imediatamente destinada à análise da viabilidade folicular com o auxílio do corante vital azul de trypan. O restante da suspensão foi dividida em 16 aliquotas de 0,9 mL, suspensas (v/v) em MEM+ com EG, DMSO, GLI ou PROH a 1,5 ou 3,0 M, para teste de toxicidade e criopreservação. Após o término de cada tratamento, a viabilidade folicular foi analisada e os FOPA considerados viáveis se não corados ou não viáveis, quando corados. A análise dos dados mostrou que após o teste de toxicidade e criopreservação, em todos os crioprotetores e em ambas as concentrações, a percentagem de FOPA viáveis foi significativamente reduzida quando comparada ao controle. No teste de toxicidade, quando os crioprotetores foram comparados entre si nas mesmas concentrações, foram observadas percentagens signifIcativamente menores de FOPA viáveis no PROH 3,0 M (38,9%), apresentando-se, portanto, mais tóxico quando comparado aos demais crioprotetores. Após criopreservação, obteve-se percentagens significativamente maiores de foliculos pré-antrais viáveis quando o EG e o DMSO foram utilizados. Em conclusão, FOPA ovinos isolados podem ser criopreservados com sucesso utilizando-se D MSO e EG a 1,5 e 3,0 M.

The aim of this study was to evaluate isolated sheep preantral follicles (PF) after exposure and cryopreservation using glycerol (GLI), ethylene glycol (EG), propanediol (PROH) or dimethyl sulfoxide (DMSO) at 1.5 and 3.0 M. Each ovarian pair from 5 mixed breed adult sheeps was obtained at a local slaughterhouse and submited to follicular isolation. From the obtained suspension, one aliquot was immediately analysed with trypan blue. The remaining suspension was divided in 16 aliquots of 0.9 mL, suspended in (v /v) in MEM+with EG, DMSO, GLI or PROH at 1.5 or 3.0 M to the toxicity test and cryopreservation. After the end of each treatment, the follicular viability was analysed and the PF were classified as viable if not dyed or not viable if dyed with trypan blue. The analysis of the results showed that after the toxicity test and cryopreservation, using all cryoprotectants and at both concentrations, the percentage of viable PF was significandy reduced when compared to the control. At the toxicity test, when the cryoprotectants were compared at the same concentrations, the lowest percentage of viable preantral follicles was obtained when 3.0 M PRO H (38,9%) was used, being, more toxic when compared to the others cryoprotectants. After cryopreservation, significantly higher percentual of viable PF was observed when the EG and DMSO were used. In conclusion, sheep PF can be cryopreserved successfully using DMSO and EG at 1.5 and 3.0 M.

Degeneration rate of goat primordial follicles maintained in TCM 199 or PBS at different temperatures and incubation times

The present work has investigated the degeneration rate of goat primordial follicles in situ after preservation in PBS or TCM 199 at different temperatures and incubation times. For each animal the ovarian pair was divided into 19 fragments. One ovarian fragment was taken randomly and immediately fixed (control). The other 18 ovarian fragments were randomly distributed in tubes containing PBS or TCM 199 and stored at 4º, 20º or 39ºC for 4, 12 or 24h. The storage of ovarian fragments in PBS or TCM 199 at 20ºC for 12h and 24h or at 39ºC, in all incubation times tested, increased significantly the percentage of degenerated primordial follicles (P<0.05). In contrast, for both media tested the degeneration rate of primordial follicles preserved at 4ºC for up to 24h and at 20ºC for 4h was similar to control values (P>0.05). In conclusion, this study shows that PBS was as efficient as TCM 199 in the preservation of goat primordial follicles in situ, being the best results observed at 4ºC

Preservation of goat preantral follicles in saline or coconut water solution

The present study investigated the efficiency of saline solution and coconut water solution in the preservation of goat preantral follicles enclosed in ovarian tissue, at different temperatures and for different incubation periods. At the slaughterhouse, the ovarian pair was divided into 19 fragments; one ovarian fragment was immediately fixed for histology (control-time zero). The other 18 ovarian fragments were preserved in both solutions at 4ºC, 20ºC or 39ºC for 4 h, 12 h or 24 h. The histological analysis showed that the storage of ovarian fragments in both solutions at 4ºC for up to 24 h kept the percentage of normal preantral follicles similar to the control values. In contrast, preservation at 20°C or 39ºC, in either solution, reduced significantly the percentage of normal preantral follicles compared to the control values, except in saline solution at 20ºC for 4 h or in coconut water solution at 20ºC for 4 h and 12 h. In conclusion, this study shows that both solutions can be used with the same efficiency to preserve goat preantral follicles at 4°C, irrespective of the incubation time. However, to preserve goat preantral follicles at higher temperatures, coconut water solution is recommended

Effect of 0.9 percent saline solution and phosphate buffer saline at different temperatures and incubation times on the morphology of goat preantral follicles

The present work investigated the efficiency of 0.9 percent saline solution and Phosphate Buffered Saline (PBS) in the preservation of goat preantral follicles in situ at different temperatures and incubation times. The ovarian pair of each animal was divided into 19 fragments. One ovarian fragment was taken randomly and fixed (control). The other 18 fragments were randomly distributed in tubes containing 0.9 percent saline solution or PBS at 4, 20 or 39 ºC for 4, 12 or 24 h. A total of 5,921 preantral follicles were examined. The quality of preantral follicles was evaluated by classical histology. The storage of ovarian fragments in 0.9 percent saline solution or PBS at 4 ºC did not reduce significantly the percentage of morphologically normal follicles when compared with the control, except after preservation in 0.9 percent saline solution for 24 h. The storage of ovarian fragments at 20 or 39°C reduced the percentage of normal preantral follicles when compared to the control, except after preservation in PBS at 20°C for 4 h. In conclusion, this study showed for the first time that goat preantral follicles can be stored in situ successfully at 4 ºC in 0.9 percent saline solution for 12 h and in PBS for 24 h, and at 20 ºC in PBS for 4 h