ABSTRACT
AIM: To investigate whether p38 small-interfering RNA-loaded nanoparticles (p38 siRNA NPs) attenuate spinal nerve ligation (SNL)-induced neuropathic pain in rats by suppressing spinal microglia activation via p38 targeting. MATERIALS & METHODS: After synthesizing p38 siRNA NPs with sonication, physical characteristics were measured for size and zeta potential. p38 siRNA NPs were then administrated intrathecally into SNL rats if they could reduce pain behavior excellently. RESULTS: p38 siRNA NPs significantly reduced mechanical allodynia as well as microgliosis in the spinal dorsal horns of SNL rats, consistent with a downregulation of p38-related proinflammatory mediators. CONCLUSION: As p38 in the spinal microglia plays a critical role in neuropathic pain, we expect that p38 siRNA NPs could be a promising tool for the treatment of neuropathic pain.
Subject(s)
Nanoparticles/administration & dosage , Neuralgia/drug therapy , RNA, Small Interfering/administration & dosage , p38 Mitogen-Activated Protein Kinases/administration & dosage , Animals , Humans , Ligation , Microglia/drug effects , Nanoparticles/chemistry , Neuralgia/genetics , Neuralgia/physiopathology , Polylactic Acid-Polyglycolic Acid Copolymer/administration & dosage , RNA, Small Interfering/chemistry , RNA, Small Interfering/genetics , Rats , Rats, Sprague-Dawley , Spinal Nerves/drug effects , Spinal Nerves/injuries , Spinal Nerves/physiopathology , p38 Mitogen-Activated Protein Kinases/chemistry , p38 Mitogen-Activated Protein Kinases/geneticsABSTRACT
Viral replication in the liver is generally detected by cellular endosomal Toll-like receptors (TLRs) and cytosolic helicase sensors that trigger antiviral inflammatory responses. Recent evidence suggests that surface TLR2 may also contribute to viral detection through recognition of viral coat proteins but its role in the outcome of acute viral infection remains elusive. In this study, we examined in vivo the role of TLR2 in acute infections induced by the highly hepatotrophic mouse hepatitis virus (MHV) type 3 and weakly hepatotrophic MHV-A59 serotype. To address this, C57BL/6 (wild-type; WT) and TLR2 knockout (KO) groups of mice were intraperitoneally infected with MHV3 or MHV-A59. MHV3 infection provoked a fulminant hepatitis in WT mice, characterized by early mortality and high alanine and aspartate transaminase levels, histopathological lesions and viral replication whereas infection of TLR2 KO mice was markedly less severe. MHV-A59 provoked a comparable mild and subclinical hepatitis in WT and TLR2 KO mice. MHV3-induced fulminant hepatitis in WT mice correlated with higher hepatic expression of interferon-ß, interleukin-6, tumour necrosis factor-α, CXCL1, CCL2, CXCL10 and alarmin (interleukin-33) than in MHV-A59-infected WT mice and in MHV3-infected TLR2 KO mice. Intrahepatic recruited neutrophils, natural killer cells, natural killer T cells or macrophages rapidly decreased in MHV3-infected WT mice whereas they were sustained in MHV-A59-infected WT mice and MHV3-infected TLR2 KO. MHV3 in vitro infection of macrophagic cells induced rapid and higher viral replication and/or interleukin-6 induction in comparison to MHV-A59, and depended on viral activation of TLR2 and p38 mitogen-activated protein kinase. Taken together, these results support a new aggravating inflammatory role for TLR2 in MHV3-induced acute fulminant hepatitis.
Subject(s)
Hepatitis, Viral, Animal/immunology , Murine hepatitis virus/physiology , Toll-Like Receptor 2/metabolism , Acute Disease , Alanine Transaminase/blood , Animals , Aspartate Aminotransferases/blood , Cells, Cultured , Cytokines/metabolism , Female , Humans , Inflammation Mediators/metabolism , Macrophages , Mice , Mice, Inbred C57BL , Mice, Knockout , Toll-Like Receptor 2/genetics , Virus Replication/genetics , p38 Mitogen-Activated Protein Kinases/administration & dosage , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
BACKGROUND: Myocardial damage occurs immediately following severe burns even before significant reduction in blood volume. This phenomenon is called postburn "shock heart" ("cardiac shock"), the pathogenesis of which is unclear. This study was designed to investigate the role of antisense p38 alpha gene transfection in ameliorating hypoxia and burn serum-mediated myocardial cell injury. METHODS: A model of myocardial cells cultured under hypoxia and with burn serum was established. The cells were divided into control group (group C), the group cultured under hypoxia plus burn serum (group HS), and the group treated with antisense p38 alpha gene transfection (group A-p38 alpha) and cultured under hypoxia plus burn serum. Burn serum was collected from Wistar rats with 40% TBSA III degree burns. Hypoxia was produced using a mixed gas with 1% O(2). Antisense p38 alpha gene recombinants were constructed and expression of p38 alpha kinase, and NF-kappaB subunits p50, p65 and I kappa B alpha in myocardial cells were detected by Western blot. Myocardial viability was determined by tetrazolium colorimetry (MTT). Apoptosis was detected by flow cytometry. Lactate dehydrogenase (LDH) activity in cell culture supernatants was determined. Changes in TNFalpha and IL-1 beta mRNA expression were detected by RT-PCR. RESULTS: Activation of p38 alpha kinase, expression of NF-kappaB p50, NF-kappaB p65 and I kappa B protein, and TNFalpha and IL-1 beta were downregulated significantly following antisense p38 alpha gene transfection into myocardial cells treated with hypoxia plus burn serum. Myocardial apoptosis and LDH activity in cell culture supernatants decreased markedly and myocardial viability increased significantly in the antisense p38 alpha gene treated group. CONCLUSIONS: Results demonstrated that transfection of antisense p38 alpha gene diminishes myocardial cell injury mediated by hypoxia and burn serum, suggesting a new target for the prevention and treatment of myocardial damage after burn.
