Localization and quantitative expression of the calcium-sensing receptor protein in human oocytes
Part of this work was presented at the 3rd Annual Congress of the Mediterranean Society for Reproductive Medicine (MRSM), Limassol, Cyprus, 25–27 March 2004 and at the 20th Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE), Berlin, Germany, 27–30 June 2004.
Received 30 June 2005; received in revised form 3 November 2005; accepted 3 November 2005.
Objective
To investigate the expression of the calcium-sensing receptor (CaSR) protein in human oocytes at the germinal vesicle (GV) and metaphase I (MI) and II (MII) stages.
Design
Prospective study.
Setting
Academic basic research laboratory and hospital-based fertility center.
Patient(s)
Immature and supernumerary mature oocytes (n = 118) excluded from intracytoplasmic sperm injection treatment.
Intervention(s)
Immunofluorescence and Western blot with a primary antibody against human CaSR. Confocal laser scanning microscopy (CLSM) together with quantitative image analysis used to measure the fluorescence intensity variations in oocytes at GV, MI, and MII stages.
Main Outcome Measure(s)
The CaSR expression pattern as evaluated by immunostaining in denuded oocytes and cumulus cells, CLSM, and three-dimensional image reconstructions; quantitative analysis at the equatorial plane of the oocyte.
Result(s)
We identified CaSR in human oocytes and cumulus cells. The fluorescence intensity within the oocyte varied with the developmental stage, with the greatest increase at the MI stage.
Conclusion(s)
The present study demonstrates for the first time the expression and localization of CaSR protein in human oocytes. Increased CaSR protein expression in the MI stage suggests that it may be involved in the regulation of human oocyte development and maturation.
aDepartment of Animal Production, University of Bari, Bari, Italy
bDepartment of General and Enviromental Physiology, University of Bari, Bari, Italy
cAssisted Procreation Unit, Casa di Cura Santa Maria, Bari, Bari, Italy
dDepartment of Biomedical Sciences and Biotechnologies, University of Brescia, Brescia, Italy
Reprint requests: Maria Elena Dell’Aquila, Ph.D., Department of Animal Production, Faculty of Biotechnological Sciences, University of Bari, 70124, Italy (FAX: +39-080-4679883).
Financial support by Centro di Eccellenza in Genomica Comparata, Università degli Studi di Bari (CEGBA) and MIUR COFIN PRIN 2003.
ABSTRACT