Resumo

LENIS SANIN, Yasser Yohan; RESTREPO BETANCUR, Luis Fernando; OLIVERA ANGEL, Martha  e  TARAZONA MORALES, Ariel Marcel. Osmolarity effect on the diameter and the quality of in vitro matured bovine oocytes. Rev. Lasallista Investig. [online]. 2009, vol.6, n.1, pp.58-66. ISSN 1794-4449.

Ooocytes are susceptible to osmolar changes, and show some phenomena that affect the plasma membrane. Objective. To evaluate the effect of hypo and hyperosmolarity from the culture's environment on the diameter and the quality of in vitro matured oocytes. Materials and methods. 75 oocytes of excellent and good quality were use in the study. As a control the M 199 was used, suplemented with 10 % of FCS, 30 μg of FSH and 30 μg of LH (290 mOsm/l T2). The oocytes were evaluated under two osmolar concentrations: Hyperosmotic media, 497mOsm/L (T1), and hyposmotic media 150mOsm/L (T3). The diameter and the quality were measured at 0 hours and after 24 hours. Results. The oocyte diameter at 24 hours was bigger in the T3 (148,7±9.7) and smaller in the T1 (134,6±1.2). Regarding the control (147.9±11.5) (p <0.05.), no difference was found between the percentage of excellent and good quality oocytes after 24 hours of treatment T1 in comparison to the control (56 % and 60 %) (p> 0.05.), but the quality in the T3 was lower (36 %). Conclusions. It was demonstrated that the hyperosmotic media had a bigger detrimental effect on the oocytes than the hyposmotic media. It is possible that the oocytes show more mechanisms to avoid the water flow into the cytoplasm than to avoid the exit of solutes and water flow towards the outside. The necessity to adopt rigorous measurements in the quality control of osmolarity for the culture mediums used in the processes of in vitro maturation for oocytes, is evident.

Palavras-chave : Cell membrane; solutes; hypertonic; hypotonic.

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