ABSTRACT
Expression of progesterone receptor (PR) localization on spermatozoa was determined in men with normal and abnormal spermiograms. Studies were also carried out to evaluate the potential of PR as a marker of sperm function. Progesterone receptor expression on spermatozoa from men with normozoospermia (n = 8), oligozoospermia (n = 7), asthenozoospermia (n = 8), oligoasthenozoospermia (n = 7), and teratozoospermia (n = 11) was analyzed using an immunocytochemical method with monoclonal antibodies against PR, and flow cytometry using a cell-impermeable fluorescein-tagged progesterone coupled to BSA complex (P-FITC-BSA). Both methods revealed significantly fewer (P < 0.05) PR-positive spermatozoa in men with oligozoospermia, asthenozoospermia, oligoasthenozoospermia, and teratozoospermia compared with men with normozoospermia, thereby suggesting that down-regulation of PR expression in spermatozoa may be one of the causes of male infertility. Spermatozoa from men with normozoospermia (n = 12), oligozoospermia (n = 12), asthenozoospermia (n = 12), oligoasthenozoospermia (n = 9), and teratozoospermia (n = 10) were exposed to low osmotic conditions in the hypoosmotic swelling (HOS) test and then analyzed for PR expression using P-FITC-BSA complex. A significantly higher percentage (P < 0.05) of spermatozoa with physiologically active plasma membrane (HOS+) lacked PR expression (HOS+PR-) in all categories of men with infertility, thereby suggesting that compared to the HOS test, PR expression is a better indicator of sperm function. Furthermore, PR expression in spermatozoa showed a strong (P < 0.05) positive correlation with their ability to undergo an in vitro acrosome reaction. This was observed in all study groups (i.e., normozoospermia, r = 0.8545; oligozoospermia, r = 0.8711; asthenozoospermia, r = 0.7645; oligoasthenozoospermia, r = 0.9003; and teratozoospermia, r = 0.8676). This suggests a potential role for PR in the events leading to the acrosome reaction in sperm.
Subject(s)
Fluorescein-5-isothiocyanate/analogs & derivatives , Infertility, Male/metabolism , Receptors, Progesterone/analysis , Spermatozoa/chemistry , Spermatozoa/physiology , Acrosome/chemistry , Acrosome Reaction , Antibodies, Monoclonal , Cell Membrane/physiology , Cell Size , Flow Cytometry , Fluorescent Dyes , Humans , Hypotonic Solutions , Immunohistochemistry , Male , Osmolar Concentration , Receptors, Progesterone/physiology , Serum Albumin, Bovine , Spermatozoa/ultrastructureABSTRACT
The present study, to our knowledge, is the first to demonstrate presence of progesterone receptor (PR) transcript in human spermatozoa. The study shows the presence of low copy number PR mRNA in mature human spermatozoa. The PR transcript in spermatozoa was detected by reverse transcriptase-polymerase chain reaction using primers specific for the hormone binding domain and the DNA binding domain of the conventional uterine PR. Further, the cDNA sequence of the partial PR transcript from spermatozoa was found to be identical to the region spanning nucleotides 2694 to 3230 of the conventional PR full-length cDNA sequence. This study also indirectly suggests that the PR protein indeed is an intrinsic sperm protein and is not acquired through proteinaceous secretions of accessory reproductive organs.
