Quantification of connexin43 gap junctions in porcine myometrium by confocal microscopy and stereology.

The aim of this study was to quantify the number and size of connexin43 (Cx43) gap junctions in the circular and longitudinal layers of myometrium of the non-pregnant pig. We developed a novel approach to measure the mean surface area (s), numerical density (N(v)) and surface density (S(v)) of gap junctions using confocal microscopy and stereological analysis. Immunolabelled Cx43 gap junctions were measured in the subendometrial and deep regions of the circular layer and in the longitudinal layer of the myometrium of pre-pubertal pig and mature pig at pre-ovulatory and secretory stages of the oestrous cycle. In the circular subendometrial region, all investigated stereological parameters of Cx43 gap junctions (s, N(v) and S(v)) were significantly higher (p<0.05) than those of the circular deep region and the longitudinal layer in all three groups of animals. These results indicate the large-scale heterogeneity of the number and size of Cx43 gap junctions across the myometrium in non-pregnant pig and emphasize the existence of functional diversity among myometrial cells.