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Background@#Inflammation is known to underlie the pathogenesis in neuropathic pain. This study investigated the anti-inflammatory and neuroprotective mechanisms involved in antinociceptive effects of co-administration of acetaminophen and L-carnosine in chronic constriction injury (CCI)-induced peripheral neuropathy in male Wistar rats. @*Methods@#Fifty-six male Wistar rats were randomly divided into seven experimental groups (n = 8) treated with normal saline/acetaminophen/acetaminophen + L-carnosine. CCI was used to induce neuropathic pain in rats. Hyperalgesia and allodynia were assessed using hotplate and von Frey tests, respectively. Investigation of spinal proinflammatory cytokines and antioxidant system were carried out after twenty-one days of treatment. @*Results@#The results showed that the co-administration of acetaminophen and Lcarnosine significantly (P < 0.001) increased the paw withdrawal threshold to thermal and mechanical stimuli in ligated rats compared to the ligated naïve group.There was a significant (P < 0.001) decrease in the levels of nuclear factor kappa light chain enhancer B cell inhibitor, calcium ion, interleukin-1-beta, and tumour necrotic factor-alpha in the spinal cord of the group coadministered with acetaminophen and L-carnosine compared to the ligated control group. Co-administration with acetaminophen and L-carnosine increased the antioxidant enzymatic activities and reduced the lipid peroxidation in the spinal cord. @*Conclusions@#Co-administration of acetaminophen and L-carnosine has anti-inflammatory effects as a mechanism that mediate its antinociceptive effects in CCIinduced peripheral neuropathy in Wistar rat.
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Background@#The continuous search for a novel neuropathic pain drug with few or no side effects has been a main focus of researchers for decades. This study investigated the antinociceptive and neuroprotective effects of bromelain in sciatic nerve ligation-induced neuropathic pain in Wistar rats. @*Methods@#Forty-eight Wistar rats randomly divided into eight groups comprised of six animals each were used for this study. Peripheral neuropathy was induced via chronic constriction of the common sciatic nerve. Thermal hyperalgesic and mechanical allodynia were assessed using a hotplate and von Frey filaments, respectively. The functional recovery and structural architecture of the ligated sciatic nerve were evaluated using the sciatic functional index test and a histological examination of the transverse section of the sciatic nerve. The neuroprotective effects of bromelain were investigated in the proximal sciatic nerve tissue after 21 days of treatment. @*Results@#Bromelain significantly (P < 0.05) attenuated both the thermal hyperalgesia and mechanical allodynic indices of neuropathic pain. There were improvements in sciatic function and structural integrity in rats treated with bromelain. These rats showed significant (P < 0.05) increases in sciatic nerve nuclear transcription factors (nuclear factor erythroid-derived-2-related factors-1 [NrF-1] and NrF-2), antioxidant enzymes (superoxide dismutase and glutathione), and reduced membranelipid peroxidation compared with the ligated control group. @*Conclusions@#This study suggest that bromelain mitigated neuropathic pain by enhancing the activities of nuclear transcription factors (NrF-1 and NrF-2) which increases the antioxidant defense system that abolish neuronal stress and structural disorganization.
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@# Multiple causes of neuropathic pain have been identified and its incidence is likely to increase owing to the ageing global population. Glycyrrhiza glabra (licorice) is a medicinal plant known to be a highly efficacious medicinal herb with several pharmacological effects. Few researchers have demonstrated anti-nociceptive activity of licorice acute pain. The aim of this study was to investigate the anti-nociceptive effect of prepared aqueous extract of Glycyrrhiza glabra root administration on chronic constriction injury (CCI) of sciatic nerve induced neuropathic pain and some selected inflammatory biomarkers in adult male wistar rats. Seven groups of 5 rats per group were used. Groups 1 and 2 were controls. Administration started in groups 3, 4, and 5 three days after surgery and continued for 18 days. Group 3 received 10mg/kg of Imipramine. Groups 4 and 5 received 75mg/kg and 150mg/kg of licorice respectively. Groups 6 and 7 received 75mg/kg and 150mg/kg respectively for 10 days before surgery. Paw withdrawal thresholds were assessed using hot plate method on days 3, 7, 14, and 21. On day 21, plasma level of tumor necrotic factor (TNF-α) and C-reactive protein (CRP) were determined using appropriate ELISA kits. There was significant change in pain threshold in the extract treated ameliorative groups when compared with the control and the ameliorative reference drug. TNF- alpha and CRP concentrations were significantly reduced in groups 6 and 7, compared with groups 1, 2 and 3. In conclusion, anti-nociceptive activity of licorice and its effect on TNF-α, and CRP are dose dependent and administration before surgery was more effective.
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<p><b>OBJECTIVE</b>Anacardium occidentale L. leaf is useful in the treatment of inflammation and asthma, but the bioactive constituents responsible for these activities have not been characterized. Therefore, this study was aimed at identifying the bioactive constituent(s) of A. occidentale ethanolic leaf extract (AOEL) and its solvent-soluble portions, and evaluating their effects on histamine-induced paw edema and bronchoconstriction.</p><p><b>METHODS</b>The bronchodilatory effect was determined by measuring the percentage protection provided by plant extracts in the histamine-induced bronchoconstriction model in guinea pigs. The anti-inflammatory effect of the extracts on histamine-induced paw edema in rats was determined by measuring the increase in paw diameter, after which the percent edema inhibition was calculated. The extracts were analyzed using gas chromatography-mass spectrometry to identify the bioactive constituents. Column chromatography and Fourier transform infrared spectroscopy were used respectively to isolate and characterize the constituents. The bronchodilatory and anti-inflammatory activities of the isolated bioactive constituent were evaluated.</p><p><b>RESULTS</b>Histamine induced bronchoconstriction in the guinea pigs and edema in the rat paw. AOEL, hexane-soluble portion of AOEL, ethyl acetate-soluble portion of AOEL, and chloroform-soluble portion of AOEL significantly increased bronchodilatory and anti-inflammatory activities (P < 0.05). Oleamide (9-octadecenamide) was identified as the most abundant compound in the extracts and was isolated. Oleamide significantly increased bronchodilatory and anti-inflammatory activities by 32.97% and 98.41%, respectively (P < 0.05).</p><p><b>CONCLUSION</b>These results indicate that oleamide is one of the bioactive constituents responsible for the bronchodilatory and anti-inflammatory activity of A. occidentale leaf, and can therefore be employed in the management of bronchoconstriction and inflammation.</p>
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<p><b>OBJECTIVE</b>To investigate the effects of smoking of dried leaves of Carica papaya (pawpaw) based on ethnopharmacological information which indicated that smoking of papaya leaves could influence motor performance and learning.</p><p><b>METHODS</b>Twenty-four rats were used for the study, and were grouped into four groups. Groups 1 served as the control (not exposed to papaya leaves smoke), while Groups 2, 3 and 4 were exposed to smoke from 6.25 g, 12.50 g and 18.75 g of dry pawpaw leaves respectively in a smoking chamber twice daily for 21 d with each exposure lasting for 3 min. Lastly, hippocampus was harvested in each group for histological study.</p><p><b>RESULTS</b>The results showed that there were significant (P<0.05) increases in mean of recall latencies of long-term spatial memory in the animal administered the high dose while the other groups had significantly (P<0.05) lower frequencies. Histological investigation showed signs of mild neural degeneration in high dose group and hypochromic appearance of the Nissl substance in all treated groups.</p><p><b>CONCLUSIONS</b>In conclusion, the findings from this study has demonstrated that smoking of papaya leaves has the ability to maintain an intact long-term spatial memory at all doses but retrieving such memory is faster with the low and medium dosages.</p>