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OBJECTIVE--During diabetes, retinal microglial cells are activated to release inflammatory cytokines that initiate neuronal loss and blood-retinal barrier breakdown seen in diabetic retinopathy (DR). The mechanism by which diabetes activates microglial to release those inflammatory mediators is unclear and was therefore elucidated. RESEARCH DESIGN AND METHODS--Microglia activation was characterized in streptozocin-injected rats and in isolated microglial cells using immunofluorescence, enzyme-linked immunosorbent assay, RT-PCR, and Western blot analyses. RESULTS--In 8-week diabetic retina, phospho-extracellular signal-related kinase (ERK) and P38 mitogen-activated protein kinases were localized in microglia, but not in Mueller cells or astrocytes. At the same time, Amadori-glycated albumin (AGA)-like epitopes were featured in the regions of microglia distribution, implicating a pathogenic effect on microglial activation. To test this, diabetic rats were treated intravitreally with A717, a specific AGA-neutralizing antibody, or murine IgG. Relative to nondiabetic rats, diabetic rats (IgG-treated) manifested 3.9- and 7.9-fold increases in Iba-1 and tumor necrosis factor (TNF)-α mRNAs, respectively. Treatment of diabetic rats with A717 significantly attenuated overexpression of these mRNAs. Intravitreal injection of AGA per se in normal rats resulted in increases of Iba-1 expression and TNF-α release. Guided by these results, a cultured retinal microglia model was developed to study microglial response after AGA treatment and the mechanistic basis behind this response. The results showed that formation of reactive oxygen species and subsequent activation of ERK and P38, but not Jun NH2-terminal kinase, are molecular events underpinning retinal microglial TNF-α release during AGA treatment. CONCLUSIONS--These results provide new insights in understanding the pathogenesis of early DR, showing that the accumulated AGA within the diabetic retina elicits the microglial activation and secretion of TNF-α. Thus, intervention trials with agents that neutralize AGA effects may emerge as a new therapeutic approach to modulate early pathologic pathways long before the occurrence of vision loss among patients with diabetes., During the past decade, it has become clear that inflammation is a key feature in diabetes that leads to long-term complications in specific organs, in particular the eye and kidney [...]

Background: Hepatocellular carcinoma (HCC) is the 6th prevalent cancer and the 4th leading cause of cancer-related deaths all over the world. A major challenge for sorafenib, the standard chemotherapeutic agent in HCC treatment, is the chemo-resistance. Objective: This study was conducted to evaluate the role of dantrolene as a possible antineoplastic agent in HCC, and in chemo-sensitization of sorafenib via targeting Ca+2/PI3K pathway. Methods: HCC was induced in rats using a single dose of diethylnitrosamine (DENA) (200 mg/kg, ip), followed by phenobarbital sodium (0.05%) in drinking water for 18 weeks. At the end of the 18th week, rats were allocated into 4 groups (10 rats/each), one group was left without treatment (DENA group) and the other three groups were treated with either sorafenib, dantrolene, or their combination for further 4 weeks. One day after the last injection, serum and liver tissues were collected. Liver tissue p53, VEGF, MMP-9, Cyclin D1, PI3K, and, serum AFP were assessed using immunoassay. Hepatic and serum Ca+2 were also computed. Furthermore, Ki-67 was assessed immunohistochemically. Results: Dantrolene exhibited synergistic effect when used in combination with sorafenib compared to either drug alone (p <0.05) through decreasing p53, VEGF, MMP-9, Cyclin D1, and Ki-67. In addition, dantrolene was evidenced to have an inhibitory effect on Ca+2/PI3K pathway that mediates its antineoplastic action when used alone or in combination with sorafenib. Conclusion: Dantrolene exerted antineoplastic effect as well as augmented sorafenib antineoplastic activity via the intervention of Ca+2/PI3K pathway, manifested by ameliorating angiogenesis, apoptosis, proliferation and metastasis.

Nuclear Factor kappa B (NF-κB) is a key transcriptional regulator that plays important roles in the pathogenesis of hepatic inflammation and fibrosis in chronic liver diseases. NF-κB activation leads to production of pro-inflammatory and fibrogenic cytokines. Glycyrrhizin (GL) is reported to suppress liver fibrosis and cirrhosis. Omega-3 fatty acids (ω-3) play an anti-inflammatory role and they are reported to decrease hepatic injury in Thioacetamide (TAA) fibrotic model. We investigated the effects of GL and ω-3 on liver inflammation and fibrosis in rats and clarified the effects of these natural compounds on NF-κB level. 50 male Wistar rats randomized to 5 groups: Control group and 4 groups received TAA 200 mg/kg i.p. twice weekly for 8 weeks: TAA group, GL group (received GL 25 mg/kg daily by oral tube), ω-3 group (received ω-3150 mg/kg daily by oral tube), (GL+ω-3) group (received similar combined doses of both natural compounds). GL and ω-3 alone or in combination protected the liver from TAA hepatotoxic effects as they significantly decreased serum AST activity and serum total bilirubin level, they also significantly increased serum albumin and total protein levels. The hepatoprotective effects of GL and ω-3 were confirmed by the histopathological analysis as they significantly reduced the necroinflammatory scores and the extent of fibrosis. GL and ω-3 significantly decreased liver malondialdehyde level (P < 0.005), liver NF-ƙB level (P < 0.005) and its tissue expression as detected by immunohistochemistry. In conclusion, glycyrrhizin and omega-3 fatty acids alone or in combination have potent anti-inflammatory, anti-oxidant and anti-fibrotic effects.

In diabetic retinopathy (DR), abnormalities in vascular and neuronal function are closely related to the local production of inflammatory mediators whose potential source is microglia. A2Aadenosine receptor (A2AAR) has been shown to possess anti-inflammatory properties that have not been studied in DR. Here, we evaluate the role of A2AAR and its underlying signaling in retinal complications associated with diabetes. Initial studies in wild-type mice revealed that the treatment with the A2AAR agonist resulted in marked decreases in hyperglycemia-induced retinal cell death and tumor necrosis factor (TNF)-α release. To further assess the role of A2AAR in DR, we studied the effects of A2AAR ablation on diabetes-induced retinal abnormalities. Diabetic A2AAR−/−mice had significantly more terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cells, TNF-α release, and intercellular adhesion molecule-1 expression compared with diabetic wild-type mice. To explore a potential mechanism by which A2AAR signaling regulates inflammation in DR, we performed additional studies using microglial cells treated with Amadori-glycated albumin, a risk factor in diabetic disorders. The results showed that activation of A2AAR attenuated Amadori-glycated albumin-induced TNF-α release in a cAMP/exchange protein directly activated by cAMP-dependent mechanism and significantly repressed the inflammatory cascade, C-Raf/extracellular signal-regulated kinase (ERK), in activated microglia. Collectively, this work provides pharmacological and genetic evidence for A2AAR signaling as a control point of cell death in DR and suggests that the retinal protective effect of A2AAR is mediated by abrogating the inflammatory response that occurs in microglia via interaction with C-Raf/ERK pathway.