en Original Article Original Article <strong>Background:</strong> The mitogen-activated protein kinase (MAPK) pathway is one of the major signaling pathways that transmit intracellular signals initiated by extracellular stimuli to the nucleus. The stress-activated protein kinase (SAPK)/c-Jun NH2-terminal kinase is a subfamily of MAP kinases implicated in cytokine and stress responses.<br> <strong>Objective:</strong> In this study, we have examined total and phosphorylated c-Jun in the mural and cumulus granulosa cells, and investigated also whether c-Jun can be responsible for the difference in the expression of apoptosis between mural and cumulus regions.<br> <strong>Materials and Methods:</strong> A total of 14 consecutive couples participating in IVF program were investigated. Aspirated follicular fluid was transferred into tissue culture dishes and oocyte-cumulus cells complexes were isolated. The cells were centrifuge and fixed with Bouin&rsquo;s solution and then were put on a glass slide. After fixation, the slides were stained by immunocytochemistry method. The incidence of apoptotic granulosa cells was examined by a fluorescence microscope.<br> <strong>Results:</strong> The incidence of apoptotic granulosa cells was 1.27 &plusmn; 0.12 in the mural region and 0.38 &plusmn; 0.07 in the cumulus regions. All mural and cumulus cells expressed total c-Jun in 7 patients while phosphorylated c-Jun was also expressed in all cells of the other 7 patients. There was no difference between apoptotic and nonapoptotic cells in the expression of total and phosphorylated c-Jun.<br> <strong>Conclusion:</strong> C-Jun may not be responsible for apoptotic effect on mural and cumulus cells. Apoptosis, C-Jun, Granulosa cells, In vitro fertilization, Human 175 180 http://ijrm.ir/browse.php?a_code=A-10-549-260&slc_lang=en&sid=1 Hassan Hassani Bafrani hasanhasani@yahoo.com Yes Department of Anatomy and Embryology, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran Hidekazu Saito No Department of Obstetrics and Gynecology, School of Medicine, Yamagata University of Medical Sciences, Yamagata, Japan