Résumé
Background: Sericin, because of its ability to remove free radicals and its antioxidant properties, has been used to successfully cryopreserve various mammalian cell types. However, the effects of sericin on cryopreservation of mouse sperm has not been reported
Objective: The current study intended to determine the protective role of different concentrations of sericin [0, 0.25, 0.5, and 0.75%] on mouse spermatozoa during cryopreservation, in addition to its effect on in vitro fertilization and subsequent embryo development
Materials and Methods: Mouse sperm from epididymides were frozen in cryoprotective agent with 18% raffinose, 3% skim milk, and different concentrations of sericin [0, 0.25, 0.5, 0.75%]. Thawed sperm were used for in vitro fertilization. The obtained embryos were cultured in Ksom medium for 6 days. The post-thawed motility, viability, fertilizing ability, and subsequent development to the 2-cell embryo and blastocyst stages were evaluated
Results: Our findings show that frozen-thawed sperm cells with 5% sericin indicate significantly [p = 0.0001] percentages of survivability and motility, the best fertilizing ability, as well as 2-cell embryo and blastocyst development compared to the other treated groups. There was no significant difference in survivability [p=0.8781], fertilizing ability [p=0.2458] and development of 2-cell [p=0.5136] and blastocysts embryos [p=0.0896] between 0.75% sericin and control groups
Conclusion: Supplementation by 0.5% sericin in cryoprotective agent improved frozen-thawed mouse epididymal sperm cell quality and resulted in increased embryo development
Résumé
Previous studies reported many discrepancies about the effects of corpus luteum [CL] and ovarian follicle size on the developmental competence of oocytes. The aim of this study was to investigate the effects of CL and different size of follicle on the developmental potential of bovine oocytes. After ovarian classification based on presence or absence of CL, sample follicles were placed in three groups according to their diameter; small [S; 3-6 mm], medium [M; 6-9 mm], and large [L; 10-20 mm]. Collected oocytes in each group were subjected to the in vitro embryo production processes. Results showed that, the percentages of blastocyst obtained from oocytes originating from small and medium follicles of ovaries bearing a CL [CL+S-oocytes and CL+M-oocytes, respectively] were lower [p<0.001] than those of small and medium follicles of ovaries not bearing a CL [CL-S-oocytes and CL-M-oocytes? Respectively] [30.8% and 33.6% vs. 36.9% and 38.7% respectively]. Although, the percentages of blastocyst obtained from CL-M-oocytes and CL-L-oocytes were greater[p< 0.001] than those of CL+S-oocytes and CL+M-oocytes. There were no significant differences in the percentages of blastocyst formation between controls [C-oocytes], CL-S-oocytes and CL+L-oocytes. According to the results of this study, the negative effect of CL on the developmental competence of bovine oocyte depends on the follicle size. Therefore, oocytes originating from large grown follicles were not influenced by negative effects of CL as much as those originating from small and medium follicles did