Objective. Women of childbearing age are more likely than men to experience temporomandibular disorders, with pain as the main symptom. Temporomandibular joint (TMJ) inflammation is believed to be a major reason for TMJ pain. Whether sex hormones are involved in the sexual dimorphism of TMJ inflammation and pain remains to be elucidated. The aim of this study was to examine whether estrogen affects TMJ inflammation and pain via the NF-B pathway.Methods. Female rats were divided into 6 groups: the control group, the sham-ovariectomized group, and 4 groups of ovariectomized rats treated with 17␤-estradiol at a dosage of 0 g/day, 20 g/day, 80 g/day, and 200 g/day, respectively, for 10 days and then injected intraarticularly with Freund's complete adjuvant to induce TMJ inflammation. The behavior-related and histologic effects of 17␤-estradiol were evaluated 24 hours after the induction of TMJ inflammation. NF-B activity in the synovial membrane was examined by electrophoretic mobility shift assay. The expression of the NF-B target genes tumor necrosis factor ␣, interleukin-1␤ (IL-1␤), IL-6, cyclooxygenase 2, and inducible nitric oxide synthase in the synovial membrane was examined by real-time polymerase chain reaction.Results. Treatment with estradiol potentiated TMJ inflammation in a dose-dependent manner and also exacerbated the inflammation-induced decrease in food intake. Correspondingly, estradiol potentiated the DNAbinding activity of NF-B and the transcription of its target genes in the synovial membrane. Furthermore, the estrogen receptor antagonist ICI 182780 or the NF-B inhibitor pyrrolidine dithiocarbamate partially blocked the effects of estradiol on TMJ inflammation and pain and the NF-B pathway.Conclusion. These results suggest that estradiol aggravates TMJ inflammation through the NF-B pathway, leading to the induction of proinflammatory cytokines.Temporomandibular disorders (TMDs) are an assorted set of clinical conditions characterized by pain in the temporomandibular joint (TMJ) and/or masticatory muscles. Joint inflammation is thought to be a major cause of pain in patients with TMDs (1-4). The prevalence, severity, and duration of pain in TMDs are greater in women than in men; such pain primarily affects women of childbearing age (5). Estrogen replacement therapy in postmenopausal women is associated with the highest prevalence of TMDs (6). In women with TMDs, serum estradiol levels during the luteal phase are higher than those in healthy control subjects (7), and synovial fluid estradiol levels in patients with TMDs are also higher than those in healthy control subjects (8). These observations suggest that sex hormones, particularly estrogen, may be involved in TMD-associated pain.Estrogen is involved in joint inflammation. The sex hormone 17␤-estradiol enhances the secretion of matrix metalloproteinases in synoviocytes (9). It also enhances interleukin-1␤ (IL-1␤)-induced secretion of IL-6 from synoviocytes in rheumatoid arthritis (10).

BackgroundMounting evidence indicates that children who experience abuse and neglect are prone to chronic diseases and premature mortality later in life. One mechanistic hypothesis for this phenomenon is that early life adversity alters the expression or functioning of the glucocorticoid receptor (GR) throughout the course of life and thereby increases sensitivity to inflammatory stimulation. An exaggerated pro-inflammatory response is generally considered to be a key cause of postoperative cognitive dysfunction (POCD). The aim of this study was to examine the effects of early life adversity on cognitive function and neuroinflammation after sevoflurane anesthesia in adult rats and to determine whether such effects are associated with the epigenetic regulation of GR.MethodsWistar rat pups were repeatedly subjected to infant maternal separation (early life stress) from postnatal days 2–21. In adulthood, their behavior and the signaling of hippocampal pro-inflammatory factors and nuclear factor-kappa B (NF-κB) after sevoflurane anesthesia were evaluated. We also examined the effects of maternal separation (MS) on the expression of GR and the DNA methylation status of the promoter region of exon 17 of GR and whether behavioral changes and neuroinflammation after anesthesia were reversible when the expression of GR was increased by altering DNA methylation.ResultsMS induced cognitive decline after sevoflurane inhalation in the Morris water maze and context fear conditioning tests and enhanced the release of cytokines and the activation of astrocyte intracellular NF-κB signaling induced by sevoflurane in the hippocampus of adult rats. Blocking NF-κB signaling by pyrrolidine dithiocarbamate (PDTC) inhibited the release of cytokines. MS also reduced the expression of GR and upregulated the methylation levels of the promoter region of GR exon 17, and such effects were reversed by treatment with the histone deacetylase inhibitor trichostatin A (TSA) in adult rats. Moreover, TSA treatment in adult MS rats inhibited the overactivation of astrocyte intracellular NF-κB signaling and the release of cytokines and alleviated cognitive dysfunction after sevoflurane anesthesia.ConclusionsEarly life stress induces cognitive dysfunction after sevoflurane anesthesia, perhaps due to the aberrant methylation of the GR gene promoter, which reduces the expression of the GR gene and facilitates exaggerated inflammatory responses.

Specificity protein 1 (Sp1) is often overexpressed in cancer cells. Its binding sites are known to exist in the phosphatase and tension homolog deleted on chromosome 10 (PTEN) promoter. In this study, we hypothesized that Sp1 negatively regulates PTEN expression. We used several cell lines to determine the effects of Sp1. The results showed that Sp1 overexpression inhibited the expression and promoter activity of PTEN and correspondingly upregulated AKT phosphorylation, whereas Sp1 knockdown upregulated the expression and promoter ability of PTEN and downregulated AKT phosphorylation. Moreover, a series of deletion and site-directed mutations of the PTEN promoter indicated that Sp1 can inhibit PTEN promoter activity through a specific Sp1-binding site at the PTEN core promoter in vivo. Meanwhile, non-acetylated Sp1, with its loss of DNA binding activity, failed to inhibit the expression and promoter activity of PTEN. Histone deacetylase 1 was necessary for Sp1 to inhibit PTEN expression. The inverse expression of Sp1 and PTEN was found in tongue cancer cells and salivary adenoid cystic cancer (SACC)-LM cells (possessing higher potential for lung metastasis than SACC-83) as compared with that in adjacent normal tissue and SACC-83 cells, respectively. Sp1 knockdown decreased the migration and invasion of SACC-LM cells, whereas Sp1 overexpression increased the migration and invasion of SACC-83 cells. Overall, these results suggest that Sp1 is involved in the development and invasiveness of cancer through inhibition of PTEN.

Ketamine has been reported to cause neonatal neurotoxicity via a neuronal apoptosis mechanism; however, no in vivo research has reported whether ketamine could affect postnatal neurogenesis in the hippocampal dentate gyrus (DG). A growing number of experiments suggest that postnatal hippocampal neurogenesis is the foundation of maintaining normal hippocampus function into adulthood. Therefore, this study investigated the effect of ketamine on hippocampal neurogenesis. Male Sprague-Dawley rats were divided into two groups: the control group (equal volume of normal saline), and the ketamine-anesthesia group (40 mg/kg ketamine in four injections at 1 h intervals). The S-phase marker 5-bromodeoxyuridine (BrdU) was administered after ketamine exposure to postnatal day 7 (PND-7) rats, and the neurogenesis in the hippocampal DG was assessed using single- or double-immunofluorescence staining. The expression of GFAP in the hippocampal DG was measured by western blot analysis. Spatial reference memory was tested by Morris water maze at 2 months after PND-7 rats exposed to ketamine treatment. The present results showed that neonatal ketamine exposure significantly inhibited neural stem cell (NSC) proliferation, decreased astrocytic differentiation, and markedly enhanced neuronal differentiation. The disruptive effect of ketamine on the proliferation and differentiation of NSCs lasted at least 1 week and disappeared by 2 weeks after ketamine exposure. Moreover, the migration of newborn neurons in the granule cell layer and the growth of astrocytes in the hippocampal DG were inhibited by ketamine on PND-37 and PND-44. Finally, ketamine caused a deficit in hippocampal-dependent spatial reference memory tasks at 2 months old. Our results suggested that ketamine may interfere with hippocampal neurogenesis and long-term neurocognitive function in PND-7 rats. These findings may provide a new perspective to explain the adult neurocognitive dysfunction induced by neonatal ketamine exposure.

Macrophages play a major role in joint inflammation. Estrogen is involved in rheumatoid arthritis and temporomandibular disorders. However, the underlying mechanism is still unclear. This study was done to verify and test how estrogen affects M1/M2-like macrophage polarization and then contributes to joint inflammation. Female rats were ovariectomized and treated with increasing doses of 17β-estradiol for 10 d and then intra-articularly injected with CFA to induce temporomandibular joint (TMJ) inflammation. The polarization of macrophages and expression of cadherin-11 was evaluated at 24 h after the induction of TMJ inflammation and after blocking cadherin-11 or estrogen receptors. NR8383 macrophages were treated with estradiol and TNF-α, with or without blocking cadherin-11 or estrogen receptors, to evaluate the expression of the M1/M2-like macrophage-associated genes. We found that estradiol increased the infiltration of macrophages with a proinflammatory M1-like predominant profile in the synovium of inflamed TMJ. In addition, estradiol dose-dependently upregulated the expressions of the M1-associated proinflammatory factor inducible NO synthase (iNOS) but repressed the expressions of the M2-associated genes IL-10 and arginase in NR8383 macrophages. Furthermore, estradiol mainly promoted cadherin-11 expression in M1-like macrophages of inflamed TMJ. By contrast, blockage of cadherin-11 concurrently reversed estradiol-potentiated M1-like macrophage activation and TMJ inflammation, as well as reversed TNF-α–induced induction of inducible NO synthase and NO in NR8383 macrophages. The blocking of estrogen receptors reversed estradiol-potentiated M1-like macrophage activation and cadherin-11 expression. These results suggested that estradiol could promote M1-like macrophage activation through cadherin-11 to aggravate the acute inflammation of TMJs.