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Evaluación de dos métodos de criopreservación de embriones sobre las tasas de sobrevivencia in vitro y preñez en llamas
| Content Provider | Semantic Scholar |
|---|---|
| Author | Eslava, Vásquez Elizabeth, Martha |
| Copyright Year | 2008 |
| Abstract | The aim of the present study was to evaluate the effect of two cryopreservation methods on the llama embryo in Vivo and in vitro survival. Seventy three hatched blastocysts were collected non-surgically at day 6.5 after mating from llamas treated with 1000 IU eCG, and were randomly allocated to each one of three experimental groups: Control (n=14), Vitrification (n=30) and slow freezing (n=29). Vitrification: Embryos were exposed to vitrification solution (20 % glycerol (GLY) + 20% ethylene glycol (EG) + 0.5M sucrose + 10 % Fetal Calf Serum (FCS) + 50 μg/ ml gentamicin sulfate) in two steps, and after loading into 0.25 ml straws, were plunged into liquid nitrogen. Straws were thawed in a 37 oC waterbath for 1min and automatically mixed with 0.5 M and 0.2 M sucrose solutions. Slow freezing: Embryos were exposed to PBS 1.5 M EG + 10 % FCS + 50 μg/ ml gentamicin sulfate, loaded in 0,25 ml straws and cooled 3 hours inside refrigerator, at 0,13 °C/min cooling rate from 26 °C until 5°C. Then straws were transfer into nitrogen tank, where it was followed temperature decrease at 5°C /min, from 5°C until 20°C, for 5 min, finally were plunged into liquid nitrogen. After thawing cryoprotectant was removed using dilution solutions, 0.25 M and 0.12 M sucrose. All embryos from control group and 50% from both cryopreservation groups were evaluated in Vivo: they were directly transferred into previously synchronized recipients; but cryopreservated embryos were first cultured in PBS+ 20% FCS for 2 h in PBS+ 20% FCS, inside of oven at 35°C. Pregnancy rate was 30.77 % (4/13), 16.67 % (2/12) y 0 % (0/11) to recipients which received control, vitrified and freezing embryos, respectively; diagnosed between 20 and 30 days of pregnancy, by transrectal ultrasound, it was not observed significant statistic difference (p<0.05). In Vitro evaluation cryopreservated embryos were cultured in PBS + 20 % FCS under 5 % CO2, 20 % O2 , 75% N2 at 39°C for 1 h., then morphology and reexpansion were recorded. Reexpansion of vitrified and freezing embryos was 75 % (9/12) and 57.14 % (4/7), respectively; which were not significantly different (p<0.05). It was observed that both cryopreservation methods decreased embryo quality post thawing, being higher in freezing embryos, by determining morphology characteristics and abnormal changes appearance on in Vivo and in Vitro evaluated embryos. Control group were not In vitro evaluated. Data were analyzed using Chi-square, Exact Fisher and one way-ANOVA to in Vivo evaluation and Exact Fisher and T-Student test to in Vitro evaluation, respectively. Results permit to conclude that vitrification could be the suitable method to llama embryo cryopreservation. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://cybertesis.unmsm.edu.pe/bitstream/handle/cybertesis/1248/Vasquez_em.pdf;jsessionid=31DDDA7DA89821E9E03006AFC26A4268?sequence=1 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
