Intrathecal Injection of Spironolactone Attenuates Radicular Pain by Inhibition of Spinal Microglia Activation in a Rat Model

Microglia might play an important role in nociceptive processing and hyperalgesia by neuroinflammatory process. Mineralocorticoid receptor (MR) expressed on microglia might play a central role in the modulation of microglia activity. However the roles of microglia and MR in radicular pain were not well understood. This study sought to investigate whether selective MR antagonist spironolactone develop antinociceptive effects on radicular pain by inhibition neuroinflammation induced by spinal microglia activation.Radicular pain was produced by chronic compression of the dorsal root ganglia with SURGIFLO™. The expression of microglia, interleukin beta (IL-1β), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), NR1 subunit of the NMDA receptor (t-NR1), and NR1 subunit phosphorylated at Ser896 (p-NR1) were also markedly up-regulated. Intrathecal injection of spironolactone significantly attenuated pain behaviors as well as the expression of microglia, IL-1β, TNF-α, t-NR1, and p-NR1, whereas the production of IL-6 wasn't affected.These results suggest that intrathecal delivery spironolactone has therapeutic effects on radicular pain in rats. Decreasing the activation of glial cells, the production of proinflammatory cytokines and down-regulating the expression and phosphorylation of NMDA receptors in the spinal dorsal horn and dorsal root ganglia are the main mechanisms contributing to its beneficial effects

Cerebrolysin protects against rotenone-induced oxidative stress and neurodegeneration

Omar ME Abdel-Salam,1 Nadia A Mohammed,2 Eman R Youness,2 Yasser A Khadrawy,3 Enayat A Omara,4 Amany A Sleem51Department of Toxicology and Narcotics, 2Department of Medical Biochemistry, 3Department of Physiology, 4Department of Pathology, 5Department of Pharmacology, National Research Centre, Dokki, Cairo, EgyptAbstract: We investigated the effect of cerebrolysin, a peptide mixture used for promoting memory and recovery from cerebral stroke, on the development of oxidative stress and nigrostriatal cell injury induced by rotenone administration in rats. Rotenone 1.5 mg/kg was given subcutaneously three times weekly either alone or in combination with cerebrolysin at 21.5, 43, or 86 mg/kg. Rats were euthanized 14 days after starting the rotenone injection. Lipid peroxidation (malondialdehyde), reduced glutathione (GSH), nitric oxide (nitrite) concentrations, paraoxonase 1 (PON1), and acetylcholinesterase (AChE) activities – as well as the monocyte chemoattractant protein-1 (MCP-1) and the antiapoptotic protein Bcl-2 – were measured in the brain. Histopathology, tyrosine hydroxylase, inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), and cleaved caspase-3 immunohistochemistry were also performed. Rotenone caused a significantly elevated oxidative stress and proinflammatory response in the different brain regions. Malondialdehyde and nitric oxide concentrations were significantly increased, while GSH markedly decreased in the cerebral cortex, striatum, hippocampus, and in the rest of the brain. PON1 and AChE activities significantly decreased with respect to the control levels after rotenone application. Striatal Bcl-2 was significantly decreased while MCP-1 increased following rotenone injection. Rotenone caused prominent iNOS, TNF-α, and caspase-3 immunostaining in the striatum and resulted in markedly decreased tyrosine hydroxylase immunoreactivity in the substantia nigra and striatum. Cerebrolysin coadministered with rotenone decreased lipid peroxidation, increased GSH, and inhibited the elevation of nitric oxide induced by rotenone. Cerebrolysin also decreased the rotenone-induced decline in the PON1 and AChE activities and the rotenone-mediated changes in the striatal Bcl-2 and MCP-1 levels. The drug reduced iNOs, TNF-α, and caspase 3 expressions and increased the tyrosine hydroxylase immunoreactivity in the striatum. Cerebrolysin markedly prevented the development of neuronal damage in the cortex and striatum. These data suggest that cerebrolysin may have potential therapeutic effect in Parkinson’s disease.Keywords: brain oxidative stress, neuroinflammation, apoptosis, nigrostriatal damag