Acute morphine activates satellite glial cells and up-regulates IL-1β in dorsal root ganglia in mice via matrix metalloprotease-9

<p>Abstract</p> <p>Background</p> <p>Activation of spinal cord glial cells such as microglia and astrocytes has been shown to regulate chronic opioid-induced antinociceptive tolerance and hyperalgesia, due to spinal up-regulation of the proinflammatory cytokines such as interleukin-1 beta (IL-1β). Matrix metalloprotease-9 (MMP-9) has been implicated in IL-1β activation in neuropathic pain. However, it is unclear whether acute opioid treatment can activate glial cells in the peripheral nervous system. We examined acute morphine-induced activation of satellite glial cells (SGCs) and up-regulation of IL-1β in dorsal root ganglia (DRGs), and further investigated the involvement of MMP-9 in these opioid-induced peripheral changes.</p> <p>Results</p> <p>Subcutaneous morphine injection (10 mg/kg) induced robust peripheral glial responses, as evidenced by increased GFAP expression in DRGs but not in spinal cords. The acute morphine-induced GFAP expression is transient, peaking at 2 h and declining after 3 h. Acute morphine treatment also increased IL-1β immunoreactivity in SGCs and IL-1β activation in DRGs. MMP-9 and GFAP are expressed in DRG neurons and SGCs, respectively. Confocal analysis revealed a close proximity of MMP-9 and GFAP immunostaining. Importantly, morphine-induced DRG up-regulation of GFAP expression and IL-1β activation was abolished after <it>Mmp9 </it>deletion or naloxone pre-treatment. Finally, intrathecal injections of IL-1β-selective siRNA not only reduced DRG IL-1β expression but also prolonged acute morphine-induced analgesia.</p> <p>Conclusions</p> <p>Acute morphine induces opioid receptors- and MMP-9-dependent up-regulation of GFAP expression and IL-1β activation in SGCs of DRGs. MMP-9 could mask and shorten morphine analgesia via peripheral neuron-glial interactions. Targeting peripheral glial activation might prolong acute opioid analgesia.</p

Identification of the major chemical constituents and their metabolites in rat plasma and various organs after oral administration of effective Erxian Decoction (EXD) fraction by liquid chromatography-mass spectrometry

A simple and specific LC-DAD-ESI-MS/MS method has been developed and applied for the primary investigation of the chemical constituents absorbed or metabolized in vivo, after the rat oral administration of Erxian Decoction (EXD), a Chinese medicine prescription for menopausal syndromes. Through the online ESI-MS n analysis, a total of 35 compounds have been identified or tentatively characterized from the seven tested samples, and 13 of them were unambiguously identified through a direct comparison of the retention time, UV spectra and MS n fragmentation patterns with the authentic ones. The results showed that 21 compounds were detected from rat plasma, 20 compounds were detected from rat kidneys and adrenal glands, 19 compounds were detected from rat ovaries, 12 compounds were found in rat intestines, nine compounds were identified from rat livers and nine compounds were detected from rat brains at certain time points after oral administration of the eff ective EXD fraction. Copyright © 2009 John Wiley & Sons, Ltd.postprin

Numerical investigation of injury mechanism on the human knee of long-jumpers

Abstract : Long-jump is a vigorous athletic event with high speed. Due to so fast run-up and take-off velocities in horizontal and vertical badly injured. Based on the physical conditions of an ordinary Chinese man long-jumper, a combination of finite element analysis (FEA) and multi-body dynamics analysis (MDA) approach was tried analyzing the real and detailed long-jump process. Research results show that the maximum resultant force does appear the second phase of the long-jump and that the most notable deformation, displacement and the maximum stresses are all located at the medial sides, especially at the lateral condyle of the articular cartilage. Our results show the feasibility and effectiveness of performing MDA as a preliminary step to FEA, and provide an insight into the injury mechanism on the Human Knee of Long-jumpers.