A green tea polyphenol epigallocatechin-3-gallate enhances neuroregeneration after spinal cord injury by altering levels of inflammatory cytokines.

Spinal cord injury (SCI) is a debilitating condition which is characterized by an extended secondary injury due to the presence of inflammatory local milieu. Epigallocatechin gallate (EGCG) appears to possess strong neuroprotective properties. Here, we evaluated the beneficial effect of EGCG on recovery from SCI. Male Wistar rats were given either EGCG or saline directly to the injured spinal cord and thereafter a daily IP injection. Behavior recovery was monitored by BBB, plantar, rotarod and flat-beam tests. The levels of inflammatory cytokines were determined on days 1, 3, 7, 10 and 14 after SCI. Additionally, NF-κB pathway activity was evaluated. The results demonstrated that EGCG-treated rats displayed a superior behavioral performance in a flat beam test, higher axonal sprouting and positive remodelation of glial scar. Cytokine analysis revealed a reduction in IL-6, IL2, MIP1α and RANTES levels on days 1 and 3, and an upregulation of IL-4, IL-12p70 and TNFα 1 day following SCI in EGCG-treated rats. Treatment with EGCG was effective in decreasing the nuclear translocation of subunit p65 (RelA) of the NF-κB dimer, and therefore canonical NF-κB pathway attenuation. A significant increase in the gene expression of growth factors (FGF2 and VEGF), was noted in the spinal cord of EGCG-treated rats. Further, EGCG influenced expression of M1 and M2 macrophage markers. Our results have demonstrated a therapeutic value of EGCG in SCI, as observed by better behavioral performance measured by flat beam test, modulation of inflammatory cytokines and induction of higher axonal sprouting.

Angelica Sinensis attenuates inflammatory reaction in experimental rat models having spinal cord injury.

This study was aimed to evaluate the effect of Angelica Sinensis on experimental rat models in which spinal cord injury was induced by studying different factors. Different factors causing inflammation play a key role in pathophysiology of SCI. Here three groups of rats (n=15, each was used). These included a sham control group where only laminectomy was performed, SCI group where SCI was induced and AS/SCI group where although SCI was induced but Angelica Sinensis was also administered to study its effect and draw a comparison with control. The expression of I-kBα and NF-kB p65 was also studied using western blotting and after recording optical density (OD) values of western blots. MPO activity was used to measure the effect of 20 mg/kg Angelica Sinensis. The levels of proinflammatory cytokines TNF-α, IL-1ß and IL-6 were also studied. As compared with SCI group and sham control it was observed that Angelica Sinensis significantly reduced the expression of I-kBα and NF-kB p65, (P<0.05), while MPO activity was also significantly reduced. Proinflammatory cytokine level was also reduced in treated group as compared to both other groups. On the basis of this study we concluded that the use of 20 mg/kg Angelica Sinensis in rat models can attenuate the secondary damage caused by SCI and thus help in controlling the pathology of SCI in rats.

Erythropoietin in spinal cord injury.

Spinal cord injury (SCI) is a devastating condition for individual patients and costly for health care systems requiring significant long-term expenditures. Cytokine erythropoietin (EPO) is a glycoprotein mediating cytoprotection in a variety of tissues, including spinal cord, through activation of multiple signaling pathways. It has been reported that EPO exerts its beneficial effects by apoptosis blockage, reduction of inflammation, and restoration of vascular integrity. Neuronal regeneration has been also suggested. In the present review, the pathophysiology of SCI and the properties of endogenous or exogenously administered EPO are briefly described. Moreover, an attempt to present the current traumatic, ischemic and inflammatory animal models that mimic SCI is made. Currently, a clearly effective pharmacological treatment is lacking. It is highlighted that administration of EPO or other recently generated EPO analogues such as asialo-EPO and carbamylated-EPO demonstrate exceptional preclinical characteristics, rendering the evaluation of these tissue-protective agents imperative in human clinical trials.

Region-specific increase in glutamate release from dorsal horn of rats with adjuvant inflammation.

Glutamate is considered an important pain transmitter and responsible for inflammatory hyperalgesia, but quantitative and topographical changes in glutamate release in the dorsal horn during peripheral inflammation have not been characterized. To address this issue, image analysis with a confocal laser scanning microscope was performed for quantitatively mapping capsaicin-evoked glutamate release from the lumbar cord slice of rats following unilateral adjuvant inoculation to the hind-paw. Capsaicin induced glutamate release from laminae I, II and X in the spinal cord of the adjuvant-treated and untreated sides, without apparent release from laminae III-V. The concentration of released glutamate in laminae I, II and X was higher on the adjuvant-treated side than on the untreated side. The results suggest that adjuvant inflammation increases glutamate release from capsaicin-sensitive primary afferents in laminae I, II and X.

Intrathecal NSAIDS attenuate inflammation-induced neuropeptide release from rat spinal cord slices.

Inflammation enhances release of neuropeptides from sensory nerve terminals in the spinal cord, and this may contribute to the development of hyperalgesia. In a similar manner, proinflammatory prostaglandins also augment peptide release from sensory neurons. To ascertain whether the inflammation-induced increase in peptide release from spinal cord slices is mediated by production of these eicosanoids, we examined whether intrathecal administration of nonsteroidal antiinflammatory drugs (NSAIDS) could attenuate the effects of inflammation. Unilateral injection of 150 microl of complete Freund's adjuvant (CFA) into the hindpaw of adult Sprague-Dawley rats resulted in a lower threshold for paw withdrawal (hyperalgesia) on 1, 4, and 5 days after injection. Five days after the induction of inflammation, capsaicin-evoked release of immunoreactive substance P (iSP) and immunoreactive calcitonin gene-related peptide (iCGRP) was increased approximately 2-fold in slices of cord tissue from the side ipsilateral to CFA injection, compared to spinal cord slices from the non-inflamed side. Intrathecal administration of 1 microl/h of 10 nmol/microl solution of the NSAID, ketorolac, for 1 day prior to and throughout the inflammation significantly attenuated the inflammation-induced increase in capsaicin-evoked release of both peptides without altering release in cord tissue from the non-inflamed side. Systemic administration of the same amount of ketorolac did not attenuate the effect of inflammation on peptide release. Intrathecal administration of 16 nmol/h (S)-ibuprofen, before and throughout the inflammation, also significantly attenuated the increase in evoked neuropeptide release associated with inflammation, whereas (R)-ibuprofen was ineffective. These results suggest that inhibition of cyclooxygenase at the level of the spinal cord attenuates the augmentation of neuropeptide release induced by peripheral inflammation, and provide further evidence for an action of prostaglandins at central terminals of sensory neurons during inflammation.