Follicular Size is Associated with the Levels of Transcripts and Proteins of Selected Molecules Responsible for the Fertilization Ability of Oocytes of Puberal Gilts

Abstract

Abstract. The maturation and developmental competence of the oocyte is acquired during folliculogenesis. It is still unclear whether follicle size is associated with the levels of transcript and protein encoding molecules contributing to the fertilization ability of the porcine oocyte. Follicles were dissected from porcine ovaries after slaughter and classified as small (< 3 mm), medium (3-5 mm) or large (>5 mm), aspirated cumulus-oocyte complexes were cultured in standard porcine IVM culture medium (TCM 199) for 44 h. In developmentally competent oocytes, assessed by determining the activity of glucose-6-phosphate dehydrogenase (G6PDH) using a brilliant cresyl blue (BCB) test, real-time quantitative PCR reaction methods, western-blot and confocal microscopy analysis were applied to determine the transcript levels of porcine zona pellucida glycoproteins pZP1, pZP2, pZP3, pZP3 alpha and integrins beta 1 and beta 2, as well as the levels of pZP3 and integrin beta 2 proteins. We observed significantly higher levels of pZP1, pZP3 and integrin beta1 and beta2 transcripts in oocytes collected from medium follicles as compared with small follicles (P<0.001). Moreover, we found an increased content of all investigated mRNAs in oocytes isolated from large follicles as compared with small follicles (P<0.001). Western-blot analysis demonstrated a higher level of pZP3 protein in oocytes isolated from large and medium follicles as compared with small follicles (P<0.001). Our results suggest that the levels of transcripts and proteins for selected molecules contributing to the fertilization ability of oocytes are associated with follicular size in puberal gilts. Key words: Follicular size, Integrins, Oocyte, Pig, ZPs glycoproteins (J. Reprod. Dev. 55: [588][589][590][591][592][593] 2009) ocyte quality has a significant influence on early embryonic development and survival, establishment and maintenance of pregnancy, fetal development and even the health of offspring in postnatal life [1][2][3][4][5]. The developmental competence of an oocyte may be affected by follicle size [6][7][8]. The growth of the oocyte within the follicle is accompanied by expression of a series of genes [9][10][11]. Some of these genes are involved in cell cycle control and meiotic progression, resulting in full meiotic competence of the oocyte [12,13]. Several other proteins are involved in cellular progress as characterized by complete developmental competence of the gamete prior to fertilization [14,15]. During the growth phase, several messenger RNA (mRNA) and their respective proteins are accumulated and stored long-term to be used after fertilization and subsequent proper embryo development [1,16]. The abilities of fertilization and embryo development are acquired by an oocyte only after a long period of growth and development. Specific follicular growth and somatic follicular cell-oocyte interactions lead to the acquisition of high developmental potential for the oocyte.The porcine zona pellucida is composed of four major glycoproteins: ZP1...

Prediction of oocyte developmental competence in ovine using glucose-6-phosphate dehydrogenase (G6PDH) activity determined at retrieval time

“…One association, evidenced in a variety of species, is the inverse relationship between G6PDH-activity and oocyte diameter [13,21,23,28,30] as observed in our study. Moreover, either oocyte volume [7], or size of originating follicle [31], associated with G6PDH-activity. In this study COCs were isolated from antral follicles by slicing methods.…”

Differences in Cytoplasmic Maturation Between the BCB+ and Control Porcine Oocytes Do Not Justify Application of the BCB Test for a Standard IVM Protocol

“…Although large amounts of data have been published on RA in oocytes and embryos of domestic animals, appropriate evidence concerning oocytes selected by the BCB test is still scarce. The only data published to date on pig oocytes, concern the RA of genes related to the properties of the zona pellucida [33, 34]. According to these studies, BCB+ oocytes contained more transcripts of genes regulating sperm-oocyte interaction compared with control oocytes.…”

The morphology of porcine oocytes is associated with zona pellucida glycoprotein 3 and integrin beta 2 protein levels--

“…However, Stankiewicz et al (2009) found several differences in the viability and size of oocytes isolated from the same polyovular follicles, indicating that even the same follicle can contain a highly heterogeneous group of oocytes. On the other hand, Antosik et al (2009) demonstrated that porcine follicular size is highly associated with the expression of genes encoding proteins responsible for the fertilization ability of oocytes. They concluded that the follicular size may be one of the most important factors determining the process of successful fertilization.…”

“…The ovaries and reproductive tract were recovered and transported to the laboratory within 10 min at 38°C in 0.9% NaCl. The oocytes were isolated from follicles of 3 to 5 mm in size, as well as from follicles greater than 5 mm in diameter if such were found, according to the procedures published by Antosik et al (2009). The recovered oocytes were randomly divided into two groups; a group of oocytes used in the present study and a second group of oocytes that were used in the recent paper by Jackowska et al (2009), described in that study.…”