Protective Effect Of Progesterone Research Articles

Progesterone improved the behavior of PC12 cells under OGD/R by reducing FABP5 expression and inhibiting TLR4/NF-κB signaling pathway

Herein, PC12 cells were applied to detect the impact of progesterone under oxygen glucose deprivation/reperfusion (OGD/R) stimulation. The cell proliferation of PC12 cells was evaluated by cell counting kit-8 assay, and the concentrations of MDA, ROS and SOD were examined by their corresponding Enzyme Linked Immunosorbent Assay kits. The invasion and migration properties of PC12 cells were evaluated by transwell and wound healing assays, respectively. The expression patterns of related genes were evaluated by western blot and qPCR. Under OGD/R stimulation, progesterone treatment could elevate the viability of PC12 cells, reduce the levels of MDA and ROS, and elevate the concentration of SOD. Moreover, progesterone treatment could strengthen the invasion and migration abilities of PC12 cells under OGD/R condition, as well as decrease the apoptosis and inflammation. FABP5 expression was significantly increased in PC12 cells under OGD/R stimulation, which was reversed after progesterone stimulation. Under OGD/R stimulation, the protective effects of progesterone on PC12 cells were strengthened after si-FABP5 treatment. The protein levels of TLR4, p-P65 NF-κB, and P65 NF-κB in OGD/R-induced PC12 cells were increased, which were inhibited after progesterone treatment. Progesterone exerted protective effects on PC12 cells by targeting FABP5 under OGD/R stimulation.

Protective effects of progesterone on pulmonary artery smooth muscle cells stimulated with Interleukin 6 via blocking the shuttling and transcriptional function of STAT3

BackgroundSex hormone paradox is a crucial but unresolved issue in the field of pulmonary artery hypertension (PAH), and is thought to be related to different pathogenic factors. Inflammation is one of pathological mechanisms of PAH development. However, effects of sex hormones on the pulmonary vasculature under the condition of inflammation are still elusive. MethodsInterleukin-6 (IL-6) was used as a representative inflammatory stimulator. Effects of 17β-estradiol or progesterone on human pulmonary artery smooth muscle cells (PASMCs) were measured under the condition of IL-6. Cell functions of proliferation and migration were measured by Alarmar Blue, EdU assay, wound-healing assay and transwell chambers. We explored further mechanisms using western blot, immunofluorescence, co-immunoprecipitation, qPCR and chromatin immunoprecipitation. ResultsOur results revealed that IL-6 promoted the proliferation of PASMCs, but progesterone could reverse the adverse effect of IL-6. The protective effect was dependent on progesterone receptor (PGR). By interacting with signal transducer and activator of transcription 3 (STAT3), activated PGR could reduce the IL-6-induced nuclear translocation of STAT3 and prevent STAT3-chromatin binding in PASMCs, leading to the decreased transcription of downstream CCND1 and BCL2. Alternatively, progesterone slightly decreased the phosphorylation of pro-proliferative Erk1/2 and Akt kinases and upregulated the anti-proliferative pSmad1-Id1/2 axis in IL-6-incubated PASMCs. ConclusionsProgesterone played a protective role on PASMCs in the context of IL-6, by blocking the functions of STAT3. Our findings might assist in explaining the clinical phenomenon of better prognosis for women with PAH.

Sexual dimorphism following in vitro ischemia in the response to neurosteroids and mechanisms of injury

BackgroundCerebral ischemic stroke is a significant cause of morbidity and mortality. Sex differences exist following stroke in terms of incidence, symptoms, outcomes and response to some treatments. Importantly, molecular mechanisms of injury, activated following ischemia may differ between the sexes and if so may account, at least in part, for sex differences seen in treatment response. Here we aimed to determine, using single-sex organotypic hippocampal slice cultures, whether the effectiveness of a potential treatment option, i.e. sex steroids, exhibited any sexual dimorphism and whether sex affected the mechanisms of apoptosis activated following ischemia.ResultsFollowing exposure to ischemia, male-derived tissue exhibited higher levels of cell death than female-derived tissue. Various sex steroid hormones, i.e. progesterone, allopregnanolone, and estradiol, were protective in terms of reducing the amount of cell death in male- and female-derived tissue whereas medoxyprogesterone acetate (MPA) was only protective in female-derived tissue. The protective effect of progesterone was abolished in the presence of finasteride, a 5α-reductase inhibitor, suggesting it was largely mediated via its conversion to allopregnanolone. To test the hypothesis that sex differences exist in the activation of specific elements of the apoptotic pathway activated following ischemia we administered Q-VD-OPH, a caspase inhibitor, or PJ34, an inhibitor of poly (ADP ribose) polymerase (PARP). Caspase inhibition was only effective, in terms of reducing cell death, in female-derived tissue, whereas PARP inhibition was only protective in male-derived tissue. However, in both sexes, the protective effects of progesterone and estradiol were not observed in the presence of either caspase or PARP inhibition.ConclusionsSex differences exist in both the amount of cell death produced and those elements of the cell death pathway activated following an ischemic insult. There are also some sex differences in the effectiveness of steroid hormones to provide neuroprotection following an ischemic insult—namely MPA was only protective in female-derived tissue. This adds further support to the notion sex is an important factor to consider when investigating future drug targets for CNS disorders, such as ischemic stroke.

Mitigating placental injuries through up-regulating DAF in experimental APS mice: new mechanism of progesterone.

Anti-phospholipid syndrome (APS) is characterized by recurrent pathological pregnancy, arterial or venous thrombosis in the presence of anti-phospholipid antibody (aPL). Complement activation is recognized as an intermediate link leading to placental thrombosis and placental inflammation in APS model mice. Decay accelerating factor (DAF, CD55), MAC-inhibitory protein (MAC-IP, CD59) and membrane co-factor protein (MCP, CD46) are important complement inhibitory proteins (CIPs) highly expressed in normal placenta to curb excessive complement activation and its mediated injuries. Anti-β2 glycoprotein I (anti-β2GPI) antibody is an important aPL. We found that placental DAF and CD46 decreased in β2GPI passively immunized APS model mice, accompanied by C3 deposition, neutrophil infiltration and increased proinflammatory cytokine levels detected in its placenta. Progesterone supplement can up-regulate DAF but not CD46 expression, curb C3 activation and decrease proinflammatory cytokines levels to reduce fetal loss frequency. Progesterone receptor antagonist (mifepristone) or knock-down DAF with specific siRNA, above the protective effects of progesterone, were significantly weakened. Another sex hormone, oestrogen, has no significant effect on placental DAF and C3 contents and fetal loss frequency in the APS mice model. This may be an important mechanism by which progesterone induces maternal-fetal immune tolerance. At the same time, it may provide evidence for the use of progesterone in APS abortion patients.

Distinct dampening effects of progesterone on the activity of nucleus tractus solitarii neurons in rat pups.

What is the central question of the study? Progesterone is considered a respiratory stimulant drug, but its effect on medullary respiratory neurons are poorly documented. We investigated whether progesterone alters spontaneous activity of neurons in the nucleus of the solitary tract (NTS). What is the main finding and its importance? In NTS neurons, progesterone decreases the action potential firing frequency in response to current injections and the amplitude of excitatory postsynaptic currents. Based on the established neuroprotective effect of progesterone against excitotoxicity resulting from insults, this inhibitory effect is likely to reflect inhibition of ion fluxes. These results are important because they further our understanding of the mechanisms underlying the diversity of respiratory effects of progesterone. Progesterone is known to stimulate breathing, but its actions on the respiratory control system have received limited attention. We addressed this issue at the cellular level by testing the hypothesis that progesterone augments excitatory currents at the level of the nucleus tractus solitarii (NTS). Medullary slices from juvenile male rats (14-17days of age) containing the commissural region of the NTS (NTScom) were incubated with progesterone (1μm) or vehicle (0.004% DMSO) for 60min. We performed whole-cell voltage-clamp recordings of spontaneous excitatory postsynaptic currents (EPSCs) in the NTScom and determined membrane properties by applying depolarizing current steps. In comparison to vehicle-treated cells, progesterone exposure attenuates the firing frequency response to current injection and reduces the EPSC amplitude without modifying the EPSC frequency or the basal membrane properties. These data do not support our hypothesis, because they indicate that incubation with progesterone attenuates intrinsic action potential generation and inhibits excitatory synaptic inputs in the NTS. Given that these results are more in line with the protective effect of progesterone against excitotoxicity resulting from various insults, we propose that progesterone acts via inhibition of ionic flux.

Progesterone treatment enhances the expansion of placental immature myeloid cells in a mouse model of premature labor

Introductionimmature-myeloid cells (IMCs) are proangiogenic bone marrow (BM)-derived cells that normally differentiate into inflammatory cells such as neutrophils, monocytes and dendritic cells (DCs). We characterized placental IMCs comparing their gene expression and subpopulations to tumor IMCs, and tested our hypothesis that progesterone that inhibits preterm labor, may affect their abundance and differentiation. Methodsdifferences between IMC-subpopulations in subcutaneous tumors versus placentas in C57BL/6 or ICR (CD-1) mice were analyzed by flow cytometry and gene expression was detected by microarrays. BM- and placental cells were incubated with or without progesterone and IMC subpopulations were analyzed. For preterm labor induction pregnant mice pretreated or not with progesterone were or were not treated with Lipopolysaccharide (LPS). Resultswe detected enrichment of granulocytic-IMCs in placentas compared to tumors, paralleled by a decrease in monocytic-IMCs. mRNA expression of placenta- versus tumor IMCs revealed profound transcriptional alterations. Progesterone treated BM-CD11b+ cells ex-vivo induced enrichment of granulocytic-IMCs and a decrease in monocytic-IMCs and DCs. LPS treatment in-vivo led to an increase in BM-IMCs in both progesterone pretreated or non-pretreated mice. In the placenta LPS decreased the IMC population while progesterone led to complete abrogation of this effect. Discussionplacental IMCs differ from tumor-IMCs in both subpopulations and gene expression. Progesterone enhances the proliferation of placenta-specific granulocytic IMCs ex-vivo and LPS induced labor is accompanied by a decrease in placental IMCs only in progesterone non-pretreated mice. We thus speculate that the protective effect of progesterone in preventing preterm labor may be explained at least in part by this specific anti-inflammatory effect.

Membrane progesterone receptors β and γ have potential as prognostic biomarkers of endometrial cancer

Endometrial cancer (EC) is one of the most common malignancies in women worldwide. EC is linked to chronic exposure to estrogens that is unopposed by protective effects of progesterone. Progesterone modulates gene expression via classical nuclear receptors, and has rapid effects via the less characterized membrane-bound progesterone receptors (mPRs) of the progestin and adipoQ receptor (PAQR) family. The presence of mPRs in EC has not been investigated to date. The aims of this study were to examine PAQR7, PAQR8 and PAQR5, which encode for mPRα, mPRβ and mPRγ, respectively, for their expression and localization in EC tissue and adjacent control endometrium. Our results reveal decreased expression of PAQR7 and PAQR8, and unaltered expression of PAQR5 in EC versus control tissue. Expression of PAQR5 was decreased in EC with higher FIGO stage versus stage IA. Immunohistochemistry revealed lower levels of mPRα and mPRβ, but higher levels of mPRγ, in EC versus control tissue. There was greater decrease in mPRβ levels in tumors with lymphovascular invasion. The analysis of the expression data associates higher PAQR5 mRNA and mPRβ protein levels with favorable patient prognosis. Immunohistochemistry showed diverse localizations of mPRs in control and cancer endometrium. In control endometrium, mPRα and mPRβ were localized mostly at the cell membranes, while mPRγ was localized in the cytoplasm and/or nucleus. In cancer endometrium, mPRα and mPRβ were detected at the cell membrane or in the cytoplasm, or both, while mPRγ was only localized in the cytoplasm. Taken together, these results imply that mPRs are involved in EC pathogenesis through effects on the development or progression of cancer. The potential role of mPRβ and mPRγ as prognostic biomarkers needs to be further assessed on a larger number of samples.

Progesterone inhibited endoplasmic reticulum stress associated apoptosis induced by interleukin-1β via the GRP78/PERK/CHOP pathway in BeWo cells.

Pre-eclampsia (PE) is a pregnancy complication characterized by new onset maternal hypertension and proteinuria. Its underlying mechanisms are unclear. This study investigated the relationship between progesterone and endoplasmic reticulum stress (ERS) associated apoptosis induced by interleukin (IL)-1β via the glucose regulated protein 78 (GRP78)/protein kinase RNA-like endoplasmic reticulum kinase (PERK)/C/EBP-homologous protein (CHOP) pathway in BeWo cells. Venous blood and placental tissues were collected from PE patients, normal pregnancy and preterm delivery cases, respectively. Progesterone serum levels were detected by enzyme-linked immunosorbent assay and ERS-related protein expression in placentas was examined by immunohistochemistry, reverse transcriptase-polymerase chain reaction and Western blot. BeWo cells were stimulated by IL-1β to induce ERS associated apoptosis in vitro. The apoptotic rate was measured by flow cytometry. The mechanism of progesterone acting on IL-1β induced ERS associated apoptosis was investigated by reverse transcriptase-polymerase chain reaction, Western blot and PERK small interfering RNA, with RU486 used as a receptor inhibitor. PE patients exhibited decreased serum levels of progesterone and activated ERS and increased ERS-related protein expression. IL-1β could induce ERS and associated cell apoptosis by activating the GRP78/PERK/CHOP signal pathway, which could be inhibited by progesterone. PERK could be upregulated and phosphorylation activated in ERS. The protective effects of progesterone could be attenuated by RU486. IL-1β could induce ERS associated cell apoptosis by activating the GRP78/PERK/CHOP signal pathway in BeWo cells and may play an important role in PE occurrence. Progesterone levels were decreased in patients with PE and seemed to have a protective effect by inhibiting ERS associated cell apoptosis.

Cellular Mechanics of Primary Human Cervical Fibroblasts: Influence of Progesterone and a Pro-inflammatory Cytokine.

The leading cause of neonatal mortality, pre-term birth, is often caused by pre-mature ripening/opening of the uterine cervix. Although cervical fibroblasts play an important role in modulating the cervix's extracellular matrix (ECM) and mechanical properties, it is not known how hormones, i.e., progesterone, and pro-inflammatory insults alter fibroblast mechanics, fibroblast-ECM interactions and the resulting changes in tissue mechanics. Here we investigate how progesterone and a pro-inflammatory cytokine, IL-1β, alter the biomechanical properties of human cervical fibroblasts and the fibroblast-ECM interactions that govern tissue-scale mechanics. Primary human fibroblasts were isolated from non-pregnant cervix and treated with estrogen/progesterone, IL-1β or both. The resulting changes in ECM gene expression, matrix remodeling, traction force generation, cell-ECM adhesion and tissue contractility were monitored. Results indicate that IL-1β induces a significant reduction in traction force and ECM adhesion independent of pre-treatment with progesterone. These cell level effects altered tissue-scale mechanics where IL-1β inhibited the contraction of a collagen gel over 6days. Interestingly, progesterone treatment alone did not modulate traction forces or gel contraction but did result in a dramatic increase in cell-ECM adhesion. Therefore, the protective effect of progesterone may be due to altered adhesion dynamics as opposed to altered ECM remodeling.

9: Progesterone promotes the expansion of proangiogenic immature myeloid cells and prevents their differentiation into inflammatory cells

Immature myeloid cells (IMCs) are bone marrow-derived cells that normally differentiate into granulocytes, macrophages, and dendritic cells (DCs) but expand in pathological conditions such as malignancy. DCs are antigen-presenting cells that regulate the immune response. We have shown that IMCs accumulate in the placenta and actively promote angiogenesis. IMCs peak in concentration during mid-pregnancy and their presence correlates with neonatal birthweight. Furthermore, labor and delivery are preceded by a decrease in IMCs and an increase in DCs populating the placenta. We hypothesized that progesterone may promote IMC population expansion while preventing their differentiation into inflammatory cells. We derived bone marrow cells from C57Bl6 pregnant mice. We isolated the CD11b+ myeloid subset by magnetic based immuno-separation, and cultured them in the presence of GMCSF and progesterone (10-7, 10-8, and 0 mM). After 5 days we analyzed cultures for the presence of Ly6CintLy6Ghi granulocytic IMCs, Ly6ChiLy6Gint monocytic IMCs and CD11c+MHCII+ DCs by flow cytometry. We also compared their presence in Lewis Lung Carcinoma tumors that were implanted subcutaneously in mice to that in placentas derived from pregnant mice. Progesterone treatment caused a dose dependent increase in granulocytic IMCs (n=3, p<0.05), accompanied by a concomitant decline in the monocytic IMCs (n=3, p<0.001). Importantly, these changes were paralleled by a decrease in DCs (n=3, p<0.05). When analyzing CD45+ hematopoietic cells in tumors and placentas, we detected a significant enrichment (P<0.01) of monocytic IMCs subpopulation in tumors compared to that in placentas. This was paralleled by a concomitant, more than 2-fold decrease (P<0.01) in granulocytic IMCs. Progesterone enhances proliferation and/or survival of placenta specific- granulocytic IMCs but not that of tumor specific- monocytic IMCs, in a dose dependent manner. Importantly, the differentiation of IMCs into DCs was abrogated by progesterone. We thus speculate that progesterone may play role in the maintenance of proangiogenic IMCs in the placenta. Inhibition of their differentiation into inflammatory cells such as DCs and neutrophils might explain, at least in part, the protective effect of progesterone in preventing preterm labor.

Effects of progesterone on hyperoxia-induced damage in mouse C8-D1A astrocytes.

IntroductionThe birth of most mammals features a dramatic increase in oxygen while placenta‐derived hormones such as β‐estradiol and progesterone plummet. In experimental newborn animals, transiently elevated oxygen concentrations cause death of neurons, astrocytes, and oligodendrocyte precursors. High oxygen has been associated with cerebral palsy in human preterm infants while progesterone is being used to prevent preterm delivery and investigated as a neuroprotective agent.MethodsIn this study, we investigated the effects of hyperoxia (80% O2 for 24, 48, and 72 h) on cultured C8‐D1A astrocytes in the presence or absence of progesterone at concentrations ranging from 10−9 to 10−5 mol/L.ResultsHyperoxia measured by methytetrazolium assay (MTT) reduced cell viability, increased release of lactate dehydrogenase (LDH), reduced carboxyfluorescein diacetate succinimidyl ester (CFSE)‐assessed cell proliferation, and downregulated Cylin D2 expression. Progesterone did not affect any of these hyperoxia‐mediated indicators of cell death or malfunctioning. Real‐time PCR analysis showed that hyperoxia caused downregulation of the progesterone receptors PR‐AB und PR‐B.ConclusionsOur experiments showed that there was no protective effect of progesterone on hyperoxia‐inducted cell damage on mouse C8‐D1A astrocytes. Down regulation of the progesterone receptors might be linked to the lack of protective effects.

Protective effects of progesterone on retinal nerve injury in acute high intraocular pressure rats

Protective effects of progesterone on retinal nerve injury in acute high intraocular pressure rats

Progesterone and cilostazol protect mice pancreatic islets from oxidative stress induced by hydrogen peroxide.

Reactive oxygen species and oxidative stress impair β-cell function and reduce insulin secretion. It has been shown that progesterone and cilostazol possess antioxidant properties. The present study was aimed to investigate in-vitro pretreatment effect of progesterone and cilostazol on insulin secretion as well as their protective effects against hydrogen peroxide-induced oxidative stress in pancreatic isolated islets from mouse. Pancreatic islets were isolated from 84 male NMRI mice (25-30 g) by collagenase digestion method and pretreated for 48 h with cilostazol (10 μM), progesterone (0.5 μM) and glibenclamide (10 μM) in culture medium. Then islets were exposed to hydrogen peroxide (H2O2. 500 μM) for 2 h. Next, culture mediums containing glucose concentration of 2.8 mM or 16.7 mM were added to them and incubated in this status for 1 h. At the end, the rate of insulin output from islets, lipid peroxidation and antioxidant enzymes activities in islet tissues were assayed. Exposure of islets to H2O2, resulted in a significant decrease in insulin secretion, superoxide dismutase and catalase activities (P < 0.001). Also islets malondialdehyde levels were increased by H2O2, after addition of 2.8 mM (P < 0.05) and 16.7 mM (P < 0.001) glucose. 48 h pretreatment of islets with cilostazol and progesterone, significantly reverted back this changes (P < 0.05). Results of present study showed that cilostazol and progesterone protect mice pancreatic islets against H2O2-induced oxidative stress. At the end, our results suggested that protective effects of progesterone and cilostazol are mediated by augmentation the antioxidant defence system of islets.

Metabolic alteration of neuroactive steroids and protective effect of progesterone in Alzheimer's disease-like rats.

A correlation between metabolic alterations of neuroactive steroids and Alzheimer's disease remains unknown. In the present study, amyloid beta (Aβ) 25-35 (Aβ25-35) injected into the bilateral hippocampus CA1 region significantly reduced learning and memory. At the biochemical level, hippocampal levels of pregnenolone were significantly reduced with Aβ25-35 treatment. Furthermore, progesterone was considerably decreased in the prefrontal cortex and hippocampus, and 17β-estradiol was significantly elevated. To our knowledge, this is the first report showing that Aβ25-35, a main etiological factor of Alzheimer's disease, can alter the level and metabolism of neuroactive steroids in the prefrontal cortex and hippocampus, which are brain regions significantly involved in learning and memory. Aβ25-35 exposure also increased the expression of inflammatory mediators, tumor necrosis factor-α and interleukin-1β. However, subcutaneous injection of progesterone reversed the upregulation of tumor necrosis factor-α and interleukin-1β in a dose-dependent manner. Concomitant with improved cognitive abilities, progesterone blocked Aβ-mediated inflammation and increased the survival rate of hippocampal pyramidal cells. We thus hypothesize that Aβ-mediated cognitive deficits may occur via changes in neuroactive steroids. Moreover, our findings provide a possible therapeutic strategy for Alzheimer's disease via neuroactive steroids, particularly progesterone.

Therapeutic Effects of Progesterone in Animal Models of Neurological Disorders

Substantial evidence supports that progesterone exerts many functions in the central and peripheral nervous system unrelated to its classical role in reproduction. In this review we first discussed progesterone effects following binding to the classical intracellular progesterone receptors A and B and several forms of membrane progesterone receptors, the modulation of intracellular signalling cascades and the interaction of progesterone reduced metabolites with neurotransmitter receptors. We next described our results involving animal models of human neuropathologies to elucidate the protective roles of progesterone. We described: (a) the protective and promyelinating effects of progesterone in experimental spinal cord injury; (b) the progesterone protective effects exerted upon motoneurons in the degenerating spinal cord of Wobbler mouse model of amyotropic lateral sclerosis; (c) the protective and anti-inflammatory effects of progesterone in the murine experimental autoimmune encephalomyelitis model of multiple sclerosis and after lysolecithin demyelination; (d) the progesterone prevention of nociception and neuropathic pain which follow spinal cord injury; and (e) the protective effect of progesterone in experimental ischemic stroke. Whenever available, the molecular mechanisms involved in these progesterone effects were examined. The multiplicity of progesterone beneficial effects has opened new venues of research for neurological disorders. In this way, results obtained in animal models could provide the basis for novel therapeutic strategies and pre-clinical studies.

Protective Effect of Progesterone during Pregnancy against Ovarian Cancer

There have been several epidemiologic studies supporting the protective role of pregnancy, although the mechanism is not clear. High level of progesterone, which is crucial in maintaining pregnancy, has been supposed to be one of the causative factors. Progesterone is produced at the corpus luteum in the early pregnancy and the placenta in the late pregnancy period. In several experimental studies, progesterone was reported to induce apoptosis of ovarian cancer cells through intrinsic and extrinsic pathways. In addition, progesterone has been shown to exert its anticancer effect through genomic and non-genomic action. The objective of this review is to discuss the protective mechanism of pregnancy against ovarian cancer focusing on the steroid hormone, progesterone.

Progesterone attenuates cerebral edema in neonatal rats with hypoxic-ischemic brain damage by inhibiting the expression of matrix metalloproteinase-9 and aquaporin-4

The aim of this study was to investigate the effects of progesterone (PROG) on blood-brain barrier (BBB) permeability, cerebral edema and the expression of matrix metalloproteinase-9 (MMP-9) and aquaporin-4 (AQP-4) in neonatal rats with hypoxic-ischemic brain damage (HIBD) and to explore the mechanism of its neuroprotective effect. Sixty 7-day-old Wistar rats were divided into sham surgery, hypoxic ischemia (HI) and drug prophylaxis (PROG) groups. HIBD animal models were established. All the animals were sacrificed after 24 h. The BBB was assessed using Evans blue. Cerebral moisture capacity was determined using the dry-wet method. MMP-9 was detected in the brain tissues using enzyme-linked immunosorbent assay. The expression of AQP-4 and MMP-9 in the cerebral cortex was observed using immunohistochemistry and real-time polymerase chain reaction. The MMP-9 levels in the cortex, BBB permeability, cerebral moisture capacity and expression of AQP-4 and MMP-9 in the HI group were significantly higher compared with those in the sham surgery group (P<0.01), and they were significantly lower in the drug prophylaxis group compared with those in the HI group (P<0.05). In conclusion, PROG reduces BBB damage and cerebral edema and inhibits MMP-9 generation to protect rat brains against HIBD. The protective effect of PROG may be correlated with downregulated expression of AQP-4 and MMP-9 in the cerebral cortex.

Altered expression of genes involved in progesterone biosynthesis, metabolism and action in endometrial cancer

Endometrial cancer (EC) is one of the most common gynecological malignancies worldwide. It is associated with prolonged exposure to estrogens that is unopposed by the protective effects of progesterone, which suggests that altered progesterone biosynthesis, metabolism and actions might be implicated in the development of EC. Our aim was to evaluate these processes through quantitative real-time PCR expression analysis in up to 47 pairs of EC tissue and adjacent control endometrium. First, we examined the expression of genes encoding proteins associated with progesterone biosynthesis: steroidogenic acute regulatory protein (STAR); a side chain cleavage enzyme (CYP11A1); and 3β-hydroxysteroid dehydrogenase/ketosteroid isomerase (HSD3B). There were 1.9- and 10.0-fold decreased expression of STAR and CYP11A1, respectively, in EC versus adjacent control endometrium, with no significant differences in the expression of HSD3B1 and HSD3B2. Next, we examined expression of genes encoding five progesterone metabolizing enzymes: the 3-keto and 20-ketosteroid reductases (AKR1C1–AKR1C3) and 5α-reductases (SRD5A1 and SRD5A2); and the opposing 20α-hydroxysteroid dehydrogenase (HSD17B2). These genes are expressed in EC and adjacent control endometrium. No statistically significant differences were seen in mRNA levels of AKR1C1, AKR1C2, AKR1C3 and SRD5A1. Expression of HSD17B2 was 3.0-fold increased, and expression of SRD5A2 was 3.7-fold decreased, in EC versus adjacent control endometrium. We also examined mRNA levels of progesterone receptors A and B (PGR), and separately the expression of progesterone receptor B (PR-B). Here we saw 1.8- and 2.0-fold lower mRNA levels of PGR and PR-B, respectively, in EC versus adjacent control endometrium. This down-regulation of STAR, CYP11A1 and PGR in endometrial cancer may lead to decreased progesterone biosynthesis and actions although the effects on progesterone levels should be further studied.

Investigation of the mechanisms of progesterone protection following oxygen–glucose deprivation in organotypic hippocampal slice cultures

This study aimed to test the hypothesis that progesterone is neuroprotective against oxygen–glucose deprivation (OGD) through its conversion to the active metabolite allopregnanolone (AlloP) and the potentiation of GABA A receptors. Organotypic hippocampal cultures were exposed to 2 h of OGD and the resulting cell death was quantified 24 h later using combined propidium iodide and Hoechst immunostaining. Initially, we confirmed, that both progesterone and AlloP were protective in terms of reducing cell death following OGD in hippocampal cultures and for both, the optimal level of protection was observed at a concentration of 0.1 μM. However, the protective effect of progesterone was absent in the presence of finasteride (10 μM) which inhibits the metabolism of progesterone to active metabolites, including AlloP. In addition, the concurrent application of picrotoxin (100 μM), a potent GABA A receptor antagonist, prevented the protection previously seen by either progesterone or AlloP alone. These results indicate that progesterone protects hippocampal cultures from cell death following OGD largely due to its conversion to AlloP and that GABA A receptors are important mediators of the protective effects of both progesterone and AlloP.

Antiepileptogenic and Antiepileptic Activity of Progesterone in the Rapid Kindling Model in PRKO Mice

Presently progesterone is undergoing NIH‐sponsored, multicenter clinical evaluation as treatment for epilepsy in women. Although the anticonvulsant effect of progesterone has long been known, the molecular mechanism underlying its protection in the brain is obscure. Progesterone‐derived GABA‐A receptor‐modulating neurosteroids could be involved in its anticonvulsant actions. However, the role of progesterone receptor (PR) is not clearly defined in the protective effects of progesterone. Here we utilized PR knockout (PRKO) mice to evaluate the antiepileptogenic and antiepileptic activity of progesterone. Progesterone was examined in female PRKO and WT controls in the kindling model under conditions of rapid kindling. Mice were subjected to stimulations via implanted electrode in the hippocampus. Progesterone treatment (100 mg/kg) prior to rapid kindling significantly suppressed subsequent kindling progression indicating antiepileptogenic effect of the steroid. In fully kindled mice, progesterone reduced the occurrence of generalized seizures. In all seizure protocols, the antiepileptogenic and antiepileptic potency of progesterone was undiminished in PRKO mice. These studies provide strong evidence that progesterone exerts both antiepileptogenic and antiepileptic effects in the kindling model, and the PR is not required for these effects of progesterone.