Cyclophilins are a family of chaperones involved in
inflammation and cell death.
Cyclophilin B is released by inflammatory cells and acts through the receptor CD147, affecting matrix
metalloproteases release, whilst
cyclophilin D participates in
hypoxia-induced apoptosis. Previous studies related
hormones like
estradiol or
prolactin to these
proteins, however, their blood concentrations across the menstrual cycle have not been determined. In this work, eleven healthy women (BMI: 21.8 kg/m2) were monitored during a single menstrual cycle, making blood extractions at follicular, periovulatory and mid-luteal phases.
Hormone and
cyclophilin levels were determined in each phase. Statistical differences were determined by repeated measures ANOVA and estimated marginal means tests, or by Friedman and Dunn-Bonferroni tests for parametric and non-parametric variables, respectively. Bivariate correlations were evaluated with the Spearman coefficient.
Cyclophilin B concentrations presented significant differences during the menstrual cycle (p = 0.012). The highest levels of this
protein were found at follicular extraction, followed by a decrease at periovulatory phase and a slight increase at mid-luteal phase.
Cyclophilin D showed the same profile, although statistical significance was not reached. This
immunophilin exhibited a positive correlation with
luteinizing hormone at periovulatory phase (r = 0.743, p = 0.009) and with
follicle stimulating hormone at mid-luteal phase (r = 0.633, p = 0.036). This is the first study describing the changes in
cyclophilin B concentrations across the menstrual cycle, as well as the association of luteinizing and follicle stimulating
hormones with
cyclophilin D. These results suggest a role of these
proteins in the cyclic inflammatory events that affect female reproductive system that should be explored.