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The anti-inflammatory effects of anti-depressants have been demonstrated recently. Doxepin, a tricyclic antidepressant drug (TCA), has some special properties in comparison with the other members of its family. It has some H1, H2, alpha-1 adrenergic and muscarinic receptor blocking effects. It revealed also anti-nociceptive and relatively potent sedative effects. This study was aimed to evaluate its possible anti-inflammatory effect in a well-established animal model. Male Wistar rats weighing 200-250 g were used in carrageenan-induced inflammatory paw edema model. The test and control drugs were injected by intraperitoneal (i.p.) and intracerebral (i.c.v.) routes. The anti-inflammatory activity of doxepin (15, 30 and 60 mg/kg, i.p. and 50 and 100 μg/rat, i.c.v.) and the reference drug, dexamethasone (2 mg/kg, i.p.) were evaluated by determination and comparison of some involved biological markers including the paw volume, cytokine levels (interleukin 6 (IL-6), IL-1β, tumor necrosis factor α (TNFα)), myeloperoxidase (MPO) activity and histopathological parameters. All i.p. doses of doxepin showed significant anti-inflammatory effect. It also significantly reduced MPO activity and cytokine levels and improved histopathologic parameters of carrageenan-injected paw tissues. I.c.v. administration of the drug did not show any significant reduction of carrageenan-induced paw edema. Although the exact mechanism of the anti-inflammatory effect of doxepin is not clear, it seems that reduced leukocyte migration and pro-inflammatory cytokines play important role in its anti-inflammatory effect. Also central sites are not involved in the anti-inflammatory effect of the drug.

Background: Damages to the peripheral fibers of sensory nerve cells and central neurons cause neuropathic pain. Manifestations of neuropathic pain occur in various conditions, including diabetes mellitus, chemotherapy, and as the side effects of some medications. Cressa cretica has long been used in traditional medicine for pain control. This study was conducted to determine the role of opioid receptors in the analgesic effect of the hydroalcoholic extract of C. cretica in an experimental model of neuropathic pain. Methods: The hydroalcoholic extract of C. cretica was prepared, and its total phenolic and flavonoid contents were standardized. Painful peripheral neuropathy was induced in rats by Chronic Constriction Injury (CCI) of the sciatic nerve. To evaluate the effects of the extract, the animals were orally given C. cretica extract (300 mg/kg), gabapentin (70 mg/kg) or normal saline (4 mL/kg) on days 3, 7, 14, and 21 after surgery, and behavioral tests were performed 45 minutes after taking the medications. To evaluate the role of the opioid receptors, Naloxone (1 mg/kg, IP) was given to rats treated with the extract 30 minutes after the extract and then the behavioral tests were performed after 15 minutes. Results: The hydroalcoholic extract of C. cretica attenuates neuropathic pain induced by CCI in rats. The extract works acutely and chronically, depending on the dosage and duration of use. Conclusion: The hydroalcoholic extract of C. cretica reduces CCI-induced neuropathic pain in rats, and Naloxone, as an opioid receptor antagonist, inhibits this effect.

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Aims: Solanum nigrum (S. nigrum) is a species of flowering plant from the Solanaceae family and one of the indigenous plants of Eurasia. Given the biological activities of this plant, like antimicrobial, antioxidant, and anti-inflammatory ones, this study assessed its effects on the healing process of second-degree burn wounds in rats. We also evaluated its antibacterial activity against common pathogens of burn wound infection (i.e., Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumanni). Methods: S. nigrum fruit extract was prepared by percolation and reflux methods. The extract was applied for the treatment of animal models with second-degree burn wounds. Parameters of wound healing and maturation, including collagen deposition, epithelialization, reduction of neutrophil migration, and angiogenesis, were evaluated. The antimicrobial activity of S. nigrum fruit extract against common pathogens of burn wound infection was assessed by the agar well diffusion method via measurement of zones of microbial growth inhibition. Results: Histological analysis showed a significant reduction in neutrophil migration by the 20% hydroalcoholic extract vs. control group (normal saline). In addition, we found that the 20% hydroalcoholic extract was more efficient than silver sulfadiazine in augmenting collagen deposition. S. nigrum hydro alcoholic extract also showed an inhibitory effect on S. aureus. Conclusion: S. nigrum 20% hydroalcoholic extract improved some of the wound healing parameters such as collagen deposition and inflammation. It also shows an inhibitory effect on S. aureus. So, it may have therapeutic effects on burns.