European journal of pharmacology
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To gain insight into the processes by which severe acute pancreatitis induced apoptosis takes place in the liver, and to observe the protective effect of resveratrol on hepatic injury, a rat model of severe acute pancreatitis was induced by administering 4% sodium taurocholate through the common biliopancreatic duct. Pancreatic and hepatic injury was assessed by histology. Serum ALT (alanine aminotransferase), AST (aspartate aminotransferase) and total bilirubin were determined by reaction rate assay, and the serum levels of TNF-alpha (tumor necrosis factor-alpha) and IL-6 (interleukin-6) were detected by ELISA (enzyme linked immunosorbent assay). ⋯ The majority of cytochrome c release occurred early in apoptosis from mitochondria, which undergo gradual hepatic impairment. The released cytochrome c can be reduced by resveratrol through both up-regulation of Bcl-2 and down-regulation of Bax and caspase-3. These data provide substantial evidence that apoptosis is involved in hepatic injury during the severe acute pancreatitis process and that resveratrol can ameliorate the situation, thus protecting liver function in rats with severe acute pancreatitis.
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Glia, particularly astrocytes and microglia, are known to play an important role in central sensitization and are strongly implicated in the exaggerated pain states. In the present study, we determined the effect of minocycline, an inhibitor of microglial activation, in acute nociception, peritonitis, and the development and maintenance of hypersensitivity following chronic constriction injury of the sciatic nerve in rats. A single dose of minocycline (30 or 100 mg/kg, i.p.) 30 min before acetic acid or zymosan injection did not attenuate the nociceptive behavior in mice. ⋯ Pre-treatment, but not post-treatment, with minocycline markedly attenuated increased pro-inflammatory cytokines release and oxidative and nitrosative stress in mononeuropathic rats. These results suggest that minocycline had no effect on acute peritoneal inflammation, nociception, and chronic administration of minocycline when started early before peripheral nerve injury could attenuate and further delays the development of neuropathic pain. Concluding, this study clearly shows minocycline, an inhibitor of microglial activation, by inhibiting the release of pro-inflammatory mediators and reducing oxidative stress prevented the development of neuropathic pain.
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Vincristine is a common anti-cancer therapy administered for the treatment of many types of tumors. Its dose-limiting side effect is the production of peripheral neuropathy, resulting in chronic neuropathic pain in many patients. An animal model of vincristine-induced sensory neuropathy was developed after repeated intraperitoneal injection in male rats and used in the present work to study the effects of PL37, an orally active complete dual inhibitor of enkephalin-catabolizing enzymes, on mechanical hypersensitivity and allodynia and on cold allodynia. ⋯ These results show that enkephalins protected from degradation by PL37 could bind to peripheral opioid receptors expressed only on C- and Adelta-mechanonociceptors but not on cold thermonociceptors. The fact that PL37 is also active on small intensity mechanical stimulus could reveal an expression of opioid receptors on low threshold mechanoreceptors in the vincrisitine-evoked pathological conditions. Thus the increase in endogenous enkephalin levels induced by PL37 offers a new way to reduced neuropathic pain without the possible side effects of opiates.
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Patients with long-standing Diabetes mellitus can develop osteopenia and osteoporosis. We have previously shown that advanced glycation endproducts reduce the bone-forming activity of osteoblasts. Bisphosphonates are used for the treatment of various bone disorders, since they reduce osteoclastic function and survival, and stimulate osteoblastic bone-forming capacity. ⋯ Nifedipine (L-type calcium channel blocker) did not affect the advanced glycation endproducts-induced decrease in osteoblastic proliferation, although it blocked the reversion of this effect by 10(-8) M Alendronate. Both advanced glycation endproducts and Alendronate inhibited the activity of intracellular neutral phosphatases. In conclusion, we show that bisphosphonates revert the deleterious actions of advanced glycation endproducts on osteoblastic cells, and that these effects of bisphosphonates depend on: (a) Ca(2+) influx through L-type voltage-sensitive channels, and (b) blockage of advanced glycation endproducts-induced reactive oxygen species generation.
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Induction of inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production is thought to have beneficial immunomodulatory effects in acute and chronic inflammatory disorders. In Raw 264.7 cells stimulated with lipopolysaccharide (LPS) to mimic inflammation, withaferin A inhibited LPS-induced expression of both iNOS protein and mRNA in a dose-dependent manner. To investigate the mechanism by which withaferin A inhibits iNOS gene expression, we examined activation of mitogen-activated protein kinases (MAPKs) and Akt in Raw 264.7 cells. ⋯ LPS-induced p65 phosphorylation, which is mediated by extracellular signal-regulated kinase (ERK) and Akt pathways, was attenuated by withaferin A treatment. Moreover, LPS-induced NO production and NF-kappaB activation were inhibited by SH-6, a specific inhibitor of Akt. Taken together, these results suggest that withaferin A inhibits inflammation through inhibition of NO production and iNOS expression, at least in part, by blocking Akt and subsequently down-regulating NF-kappaB activity.