| Both subsets of MCs including MCTC (tryptase-positive, chymase-positive) and
MC
T (tryptase-positive, chymase-negative) are present in the testis and epididymis.
Increased number of MCs, higher levels of MC-released tryptase in testis and seminal
plasma of males with fertility problems, and promoting sperm motility in individuals
with oligozoospermia after using MC blockers provide evidence that MCs may play a
role in male infertility/subfertility disturbances. MC-released tryptase and histamine
contribute to the fibrosis and may disrupt spermatogenesis. MCs not only influence
the process of spermatogenesis but also have effects on the function of other testisresiding cells. MC-derived histamine may influence the steroidogenesis of Leydig
cells by acting through H1R and H2R receptors. Additionally, the interaction between
MC-released ATP and P2X receptors expressed on the peritubular cells may induce
the production of the pro-inflammatory mediators by peritubular cells. Further investigations showed that MCs may be involved in the pathology of female infertility
during implantation, pregnancy, and abortion. In the uterus, MCT subtype is abundant in myometrium and adjacent basal layer while MCTC subtype is distributed in all
layers. MCs in response to hormones mainly estradiol and progesterone become activated and release a wide range of mediators including histamine, VEGF, proteases,
and metalloproteinases (MMPs) that have a role in different stages of pregnancy. An
increasing influx of MCs to the cervix during the pregnancy occurs that helps to the
physiologic cervical ripening. While MMPs degrade the extracellular matrix (ECM),
VEGF modulates neovascularization and histamine influences the embryo implantation. MC-derived histamine may have a positive effect during implantation due to
its participation in tissue remodeling. MC proteases including tryptase and chymase
activate the precursors of MMP2 and MMP9 to mediate ECM degradation during
the physiologic menstrual cycle. There is a line of evidence that MCs have a role in
abortion by releasing TNF-α. |