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Conjugated linoleic acid improves oocyte cryosurvival through modulation of the cryoprotectants influx rate.

Matos JE, Marques CC, Moura TF, Baptista MC, Horta AE, Soveral G, Pereira RM - Reprod. Biol. Endocrinol. (2015)

Bottom Line: The data were analyzed using the MIXED procedure and Student's T-test.CLA supplementation improves the developmental competence of vitrified/warmed and cryoprotectants exposed oocytes (p < 0.01) and reduces their membrane permeability to water (37 %, p < 0.001) and to cryoprotectants (42 %, p < 0.001).By slowing the fluxes of water and of permeant cryoprotectants, CLA contributed to improved oocyte cryosurvival and post-thawed viability.

View Article: PubMed Central - PubMed

Affiliation: Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, Universidade de Lisboa, 1649-003, Lisbon, Portugal. matos.je@gmail.com.

ABSTRACT

Background: In cryopreservation, oocytes are subjected to extreme hyperosmotic conditions, inducing large volume changes that, along with an abrupt temperature drop, interfere with their developmental competence. Our objectives in this work were to find conditions enabling an increase in oocyte cryosurvival and subsequent development.

Methods: Abattoir-derived bovine oocytes were cultured without (Control group) or with trans-10,cis-12 conjugated linoleic acid isomer (CLA group). Comparative observations were made for 1) the oocyte developmental competence after exposure to cryoprotectants followed or not by vitrification/warming, 2) the oocyte membrane permeability to water (using the non-permeant cryoprotectant sucrose) and 3) the oocyte membrane permeability to two cryoprotectants (ethylene glycol, EG, and dimethyl sulfoxide, DMSO). Mature oocytes cultured with or without CLA and vitrified/warmed or only exposed to cryoprotectants without vitrification were subjected to in vitro fertilization; embryo culture proceeded until the blastocyst stage. The oocyte membrane permeabilities to water and cryoprotectants were estimated using mature oocytes subjected to hyperosmotic challenges. For water permeability, 200 mM sucrose was used, whereas for the cryoprotectant permeability, a 10 % solution of both EG and DMSO was used. The data were analyzed using the MIXED procedure and Student's T-test.

Results: CLA supplementation improves the developmental competence of vitrified/warmed and cryoprotectants exposed oocytes (p < 0.01) and reduces their membrane permeability to water (37 %, p < 0.001) and to cryoprotectants (42 %, p < 0.001).

Conclusions: By slowing the fluxes of water and of permeant cryoprotectants, CLA contributed to improved oocyte cryosurvival and post-thawed viability. This isomer supplementation to the maturation media should be considered when designing new protocols for oocyte cryopreservation.

No MeSH data available.


Related in: MedlinePlus

Oocyte volumes during permeability assays. Representative illustration of oocyte with initial equilibrium volume Vo (left panel) and final equilibrium volume V∞ (right panel) after an osmotic challenge with sucrose to evaluate the membrane permeability to water
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Fig2: Oocyte volumes during permeability assays. Representative illustration of oocyte with initial equilibrium volume Vo (left panel) and final equilibrium volume V∞ (right panel) after an osmotic challenge with sucrose to evaluate the membrane permeability to water

Mentions: For evaluation of the osmotic water permeability coefficient Pf, Control and CLA mature oocytes were subjected to a hyperosmotic gradient of 200 mM of the non-permeant cryoprotectant sucrose. Typical volume changes can be observed from the pictures of oocytes before (initial volume Vo) and after the hyperosmotic shock when oocytes have reached their new final equilibrium volume V∞ (Fig. 2). As expected, in both groups of oocytes, a decrease in volume due to water outflow could be detected. However, observing the respective traces of relative volume change (V/Vo) (Fig. 3a), the rate at which the oocyte shrinks is visibly different (p < 0.001) between the Control and CLA oocytes, where the estimated Pf (x10−3 cm s−1, mean ± SEM) values are 14.35 ± 0.55 (n = 10) for the Control and 9.13 ± 0.62 (n = 10) for the CLA group.Fig. 2


Conjugated linoleic acid improves oocyte cryosurvival through modulation of the cryoprotectants influx rate.

Matos JE, Marques CC, Moura TF, Baptista MC, Horta AE, Soveral G, Pereira RM - Reprod. Biol. Endocrinol. (2015)

Oocyte volumes during permeability assays. Representative illustration of oocyte with initial equilibrium volume Vo (left panel) and final equilibrium volume V∞ (right panel) after an osmotic challenge with sucrose to evaluate the membrane permeability to water
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4465151&req=5

Fig2: Oocyte volumes during permeability assays. Representative illustration of oocyte with initial equilibrium volume Vo (left panel) and final equilibrium volume V∞ (right panel) after an osmotic challenge with sucrose to evaluate the membrane permeability to water
Mentions: For evaluation of the osmotic water permeability coefficient Pf, Control and CLA mature oocytes were subjected to a hyperosmotic gradient of 200 mM of the non-permeant cryoprotectant sucrose. Typical volume changes can be observed from the pictures of oocytes before (initial volume Vo) and after the hyperosmotic shock when oocytes have reached their new final equilibrium volume V∞ (Fig. 2). As expected, in both groups of oocytes, a decrease in volume due to water outflow could be detected. However, observing the respective traces of relative volume change (V/Vo) (Fig. 3a), the rate at which the oocyte shrinks is visibly different (p < 0.001) between the Control and CLA oocytes, where the estimated Pf (x10−3 cm s−1, mean ± SEM) values are 14.35 ± 0.55 (n = 10) for the Control and 9.13 ± 0.62 (n = 10) for the CLA group.Fig. 2

Bottom Line: The data were analyzed using the MIXED procedure and Student's T-test.CLA supplementation improves the developmental competence of vitrified/warmed and cryoprotectants exposed oocytes (p < 0.01) and reduces their membrane permeability to water (37 %, p < 0.001) and to cryoprotectants (42 %, p < 0.001).By slowing the fluxes of water and of permeant cryoprotectants, CLA contributed to improved oocyte cryosurvival and post-thawed viability.

View Article: PubMed Central - PubMed

Affiliation: Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, Universidade de Lisboa, 1649-003, Lisbon, Portugal. matos.je@gmail.com.

ABSTRACT

Background: In cryopreservation, oocytes are subjected to extreme hyperosmotic conditions, inducing large volume changes that, along with an abrupt temperature drop, interfere with their developmental competence. Our objectives in this work were to find conditions enabling an increase in oocyte cryosurvival and subsequent development.

Methods: Abattoir-derived bovine oocytes were cultured without (Control group) or with trans-10,cis-12 conjugated linoleic acid isomer (CLA group). Comparative observations were made for 1) the oocyte developmental competence after exposure to cryoprotectants followed or not by vitrification/warming, 2) the oocyte membrane permeability to water (using the non-permeant cryoprotectant sucrose) and 3) the oocyte membrane permeability to two cryoprotectants (ethylene glycol, EG, and dimethyl sulfoxide, DMSO). Mature oocytes cultured with or without CLA and vitrified/warmed or only exposed to cryoprotectants without vitrification were subjected to in vitro fertilization; embryo culture proceeded until the blastocyst stage. The oocyte membrane permeabilities to water and cryoprotectants were estimated using mature oocytes subjected to hyperosmotic challenges. For water permeability, 200 mM sucrose was used, whereas for the cryoprotectant permeability, a 10 % solution of both EG and DMSO was used. The data were analyzed using the MIXED procedure and Student's T-test.

Results: CLA supplementation improves the developmental competence of vitrified/warmed and cryoprotectants exposed oocytes (p < 0.01) and reduces their membrane permeability to water (37 %, p < 0.001) and to cryoprotectants (42 %, p < 0.001).

Conclusions: By slowing the fluxes of water and of permeant cryoprotectants, CLA contributed to improved oocyte cryosurvival and post-thawed viability. This isomer supplementation to the maturation media should be considered when designing new protocols for oocyte cryopreservation.

No MeSH data available.


Related in: MedlinePlus