Assesment of GLUT expression via p38 MAPK in preimplantation mouse embryo development

Approximately one-week period between fertilization and implantation is defined as preimplantation development. Apperance of any aberration in the cascade of this sequential events may affect the developmental potential and/or the survival of the embryo. Although glucose is not used in the preimplantation embryos before 8-cell stage, after compaction occurs it is the major energy source to support embryonic improvement. Glucose transport in the embryos is achieved by GLUT proteins known as facilitative glucose transporters. GLUT proteins provide adaptation capability of the the preimplantation embryos to the variable enviromental conditions and metabolic demands. p38 MAPK (mitogen-activated protein kinase) signaling pathway plays a role in many important cellular activities. It has been showed that inhibition of p38 MAPK activity by using the Cytokine Suppressive Anti-Inflammatory Drugs (CSAIDs) which is a pharmacological inhibitor of p38 MAPK resulted in decreasing the preimplantation development. In the studies conducted recently, presence of relation between p38 MAPK signalling and GLUT expression has been revealed in different somatic cell lines. These findings thought that p38 MAPK pathway may be associated with the mechanism of glucose metabolism inpreimplantation embryo. In this study, inhibition of p38 MAPK signaling pathway by using SB203580 (CSAIDTM) molecule was taken place in vitro development of 8-cell, morula and blastocyst stages at which time development is glucose-dependent in mouse (BalbC) embryos. Three groups such as the experiment group (inhibitor-treated group), the vehicle group (inhibitor-solvent treated) and the control group were formed. GLUT1 and GLUT4 expression levels were determined in the 8-cell, morula and blastocyst embryos which had been obtained from those three groups. Qualitative expression of GLUT1 and GLUT4 proteins with immunofluorescence technique and mRNA levels of these genes have been determined with qRT-PCR (quantitative real time PCR) technique. According to our results, the activity of p38 MAPK signalling pathway appears to be one of the mechanisms necessary for the continuation of preimlantation development. In case of the suppression of the activity of p38 MAPK signal inside the cell, GLUT1 protein expression in morula and blastocyst stage embryos; GLUT4 protein expression in blastocyst stage embryos was significantly decreased. In addition, in the precense of p38 MAPK inhibition, increased level of Glut1 and Glut4 mRNA expression was observed in blastocysts, but this increased was not statistically significant. As a result, p38 MAPK signalling pathway in preimplantation embryos plays a role in the regulation of GLUT1 and GLUT4 protein expression. Our study may contibute to the understanding the intracellular mechanisms that regulate preimplantation development.