Synergistic antinociceptive effect and gastric safety of the combination of docosahexaenoic acid and indomethacin in rats

Role of antioxidative activity in the docosahexaenoic acid's enteroprotective effect in the indomethacin-induced small intestinal injury model

Therapeutic effect of non-steroidal anti-inflammatory drugs (NSAIDs) has been related with gastrointestinal injury. Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid (PUFA), can prevent gastric and small intestinal damage. Nonetheless, contribution of antioxidative action in the protective effect of DHA has not been evaluated before in the small intestine injury after indomethacin treatment. Pathogenesis of NSAID-induced small intestinal injury is multifactorial, and reactive oxidative species have been related to indomethacin's small intestinal damage. The present work aimed to evaluate antioxidative activity in the protective action of DHA in the indomethacin-induced small intestinal damage. Female Wistar rats were gavage with DHA (3 mg/kg) or omeprazole (3 mg/kg) for 10 days. Each rat received indomethacin (3 mg/kg, orally) daily to induce small intestinal damage. The total area of intestinal ulcers and histopathological analysis were performed. In DHA-treated rats, myeloperoxidase and superoxide dismutase activity, glutathione, malondialdehyde, leukotriene, and lipopolysaccharide (LPS) levels were measured. Furthermore, the relative abundance of selective bacteria was assessed. DHA administration (3 mg/kg, p.o.) caused a significant decrease in indomethacin-induced small intestinal injury in Wistar rats after 10 days of treatment. DHA's enteroprotection resulted from the prevention of an increase in myeloperoxidase activity, and lipoperoxidation, as well as an improvement in the antioxidant defenses, such as glutathione levels and superoxide dismutase activity in the small intestine. Furthermore, we showed that DHA's enteroprotective effect decreased significantly LPS levels in indomethacin-induced injury in small intestine. Our data suggest that DHA's enteroprotective might be attributed to the prevention of oxidative stress.

Therapeutic effects and mechanisms of N-(9,10-anthraquinone-2-ylcarbonyl) xanthine oxidase inhibitors on hyperuricemia

Objective: To observe the antioxidative effects of N-(9,10-anthraquinone-2-ylcarbonyl) xanthine oxidase inhibitors (NAY) in vitro and in vivo models of hyperuricemia and explore the mechanism.

Methods: A classical experimental method of acute toxicity and a chronic toxicity test were used to compare the toxic effects of different doses of NAY in mice. The hyperuricemia mouse model was established by gavage of potassium oxonate in vivo. After treatment with different doses of NAY (low dose: 10 mg/kg, medium dose: 20 mg/kg, and high dose: 40 mg/kg) and allopurinol (positive drug, 10 mg/kg), observe the levels of uric acid (UA), creatinine (CRE), and urea nitrogen (BUN) in urine and serum, respectively, and detect the activities of xanthine oxidase in the liver. The hyperuricemia cell model was induced by adenosine and xanthine oxidase in vitro. The cells were given different doses of NAY (50, 100, and 200 μmol/L) and allopurinol (100 μmol/L). Then the culture supernatant UA level of the medium was measured. The next step was to detect the xanthine oxidase activity in the liver and AML12 cells, and the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammatory factors in the kidney and serum of mice. Western blot was used to detect xanthine oxidase protein expression in mouse liver tissue and AML12 cells, ASC, Caspase-1, NLRP3, GLUT9, OAT1, and OAT3 protein expression in mouse kidney tissue and HK-2 cells. Hematoxylin–eosin staining was used to stain the liver and kidney tissues of mice and observe the tissue lesions.

Results: NAY had little effect on blood routine and biochemical indexes of mice, but significantly reduced the serum UA level. NAY significantly reduced the level of UA in hyperuricemia mice and cells by inhibiting xanthine oxidase activity and reduced the levels of TNF-α, IL-6, and other inflammatory factors in serum and kidney of mice. NAY can inhibit inflammation by inhibiting the NLRP3 pathway. In addition, NAY can downregulate GLUT9 protein expression and upregulate OAT1 and OAT3 protein expression to reduce the UA level by promoting UA excretion and inhibiting UA reabsorption.

Conclusion: These findings suggested that NAY produced dual hypouricemic actions. On the one hand, it can inhibit the formation of UA by inhibiting xanthine oxidase inhibitors activity, and on the other hand, it can promote the excretion of UA by regulating the UA transporter. It provides new ideas for the development of hyperuricemia drugs in the future.

Evaluation of cytokines in protective effect of docosahexaenoic acid in experimental achilles tendinopathy rat model induced with type-1 collagenase

BACKGROUND

We aimed to investigate the effectiveness of docosahexaenoic acid (DHA) as a treatment for Achilles tendinopathy (AT) induced with type-I collagenase in rats and compare it with collagen.

METHODS

The AT model was induced with type I collagenase, and animals were randomly assigned to groups. Group 1:AT, Group 2: Collagen (7.2 mg/kg/day), Group 3:DHA (300 mg/kg/day), and Group 4:DHA (100 mg/kg/day). Right tendons of Group1 were used as a healthy control (HC). Oral treatments were applied for eight weeks. Serum tumor necrosis factor-alpha(TNF-α), matrix metalloproteinase-13 (MMP-13), and interleukin-1 beta(IL-1β) concentrations were determined by ELISA. Tendon samples were taken for histopathological evaluation and examined immunohistochemically with antibodies specific for Col1A1, TNF-α, MMP-13, IL-1β, and nitric oxide synthase-2(NOS-2). The ultimate tensile force (UTF) yield force(YF) and stiffness were measured by biomechanical assessments.

RESULTS

UTF,YF and stiffness values were increased in all treatment groups compared to the AT control, a significant increase was found in Group 2 (p < 0.05). There was severe degeneration of tendon cells in the AT control. The tendon cells in samples from Groups 2-3 were less degraded, and this was statistically significant (p < 0.05). TNF-α, MMP-13, IL-1β, and NOS-2 expressions were significantly higher in the AT control compared to the HC. In all treatment groups, their concentrations were lower than in the AT control. Serum TNF-α, MMP-13, and IL-1β levels were lower in all treatment groups (Especially in Group3 (p < 0.001)) compared to Group1.

CONCLUSION

The efficacy of high-dose DHA as a treatment for AT was investigated from biochemical, histopathological, and biomechanical perspectives. The results showed that DHA could be an alternative treatment compound to collagen.

Herbal Medicine for Pain Management: Efficacy and Drug Interactions

Complementary and alternative medicines such as herbal medicines are not currently part of the conventional medical system. As the popularity of and global market for herbal medicine grows among all age groups, with supporting scientific data and clinical trials, specific alternative treatments such as herbal medicine can be reclassified as a practice of conventional medicine. One of the most common conditions for which adults use herbal medicine is pain. However, herbal medicines carry safety concerns and may impact the efficacy of conventional therapies. Unfortunately, mechanisms of action are poorly understood, and their use is unregulated and often underreported to medical professionals. This review aims to compile common and available herbal medicines which can be used as an alternative to or in combination with conventional pain management approaches. Efficacy and safety are assessed through clinical studies on pain relief. Ensuing herb–drug interactions such as cytochrome modulation, additive and synergistic effects, and contraindications are discussed. While self-management has been recognized as part of the overall treatment strategy for patients suffering from chronic pain, it is important for practitioners to be able to also optimize and integrate herbal medicine and, if warranted, other complementary and alternative medicines into their care.

Synergistic protective effects between docosahexaenoic acid and omeprazole on the gastrointestinal tract in the indomethacin-induced injury model

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most commonly used drugs due to their antipyretic, anti-inflammatory, and analgesic properties. However, NSAIDs can cause adverse reactions, mainly gastrointestinal damage. Omeprazole (OMP) exhibits gastroprotective activity, but its protection is limited at the intestinal level. For this reason, it is essential to utilize a combination of therapies that provide fewer adverse effects, such as the combined treatment of OMP and docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid with anti-inflammatory, analgesic, and gastroprotective activities. The objective of this study was to evaluate the pharmacological interaction between DHA and OMP in a murine model of indomethacin-induced gastrointestinal damage. The gastroprotective and enteroprotective effects of DHA (0.3-10 mg/kg, p.o.), OMP (1-30 mg/kg, p.o.), or the combination treatment of both compounds (3-56.23 mg/kg, p.o.) were evaluated in the indomethacin-induced gastrointestinal damage model (30 mg/kg, p.o.). Since DHA and OMP exhibited a protective effect in a dose-responsive fashion, the ED₃₀ for each individual compound was determined and a 1:1 combination of DHA and OMP was tested. Isobolographic analysis was used to determine any pharmacodynamic interactions. Since the effective experimental dose ED₃₀ (Zexp) of the combined treatment of DHA and OMP was lower than the theoretical additive dose (Zadd; p < .05) in both the stomach and small intestine their protective effects were considered synergistic. These results indicate that the synergistic protective effects from combined treatment of DHA and OMP could be ideal for mitigating damage generated by NSAIDs at the gastrointestinal level.

Synergistic interaction between B vitamins and statins to counter nociception in rats

Evidence suggests that the antinociceptive activity of various drugs can be increased when administered in combination with B vitamins (BVs). The aim of this study was to examine the potential interaction between statins and BVs to counter nociception, the latter measured by the formalin test. Rats were orally administered atorvastatin (1, 3, 10 and 30 mg/kg), pravastatin (1, 3, 10 and 30 mg/kg), rosuvastatin (1, 3, 10 and 30 mg/kg), BVs (31, 56, 100 and 180 mg/kg) or calculated combinations of BVs with each drug. The effective dose 30 (ED₃₀ ) was calculated for each statin and BVs and subjected to isobolographic analysis, thus finding the ED₃₀ of the combinations. The antinociceptive experimental ED₃₀ values for BVs administered with atorvastatin, pravastatin or rosuvastatin were 1.53 ± 0.38, 6.74 ± 0.04 and 4.26 ± 0.39, respectively, being lower (p < .05) than the corresponding theoretical ED₃₀ : 28.02 ± 2.20, 28.17 ± 2.20 and 29.86 ± 2.21. Since BVs likely boost the antinociceptive effect of statins, these combinations could possibly be advantageous in pain management.

Pharmacodynamic interaction of 3α-hydroxymasticadienonic acid and diligustilide against indomethacin-induced gastric damage in rats

The aims of the study were to evaluate the pharmacodynamic interaction between 3α-hydroxymasticadienonic acid and diligustilide (DLG), isolated from the plants Amphiptherygium adstringens and Ligusticum porteri, respectively, using the indomethacin-induced gastric injury model, as well as their individual gastroprotective efficacy in this model. Male Wistar rats were orally administered with 3α-hydroxymasticadienonic acid, DLG or the mixture of 3α-hydroxymasticadienonic acid-DLG (at a fixed-ratio combination of 1:1, 1:3, and 3:1). Thirty minutes later, the gastric damage was induced by a single oral dose of indomethacin (30 mg/kg). Three hours later, the gastric injury (mm2 ) was determined. 3α-hydroxymasticadienonic acid and DLG as individual compounds showed a gastroprotective effect against indomethacin-induced gastric damage (p < .05). The effective dose (ED50 ) values for each compound were 6.96 ± 1.25 mg/kg for 3α-hydroxymasticadienonic acid and 2.63 ± 0.37 mg/kg for DLG. The isobolographic analysis performed showed that the combination exhibited super-additive interaction as the experimental ED50 values (Zexp) were lower than theoretical additive dose values (Zadd; p < .05). Our results identify the super-additive (synergist) interaction between 3α-hydroxymasticadienonic acid and DLG and the gastric safety of both compounds in the indomethacin-induced gastric injury model, suggesting their potential in the future as a strategy to decrease the gastric damage associated to the chronic use of nonsteroidal anti-inflammatory drugs (NSAIDs).

The antihyperalgesic effect of docosahexaenoic acid in streptozotocin-induced neuropathic pain in the rat involves the opioidergic system

Docosahexaenoic acid (DHA) is a polyunsaturated fatty acid that has shown an antinociceptive effect in multiple pain models, such as inflammatory and neuropathic pain by chronic constriction injury in rats; however, its mechanism of action is still not well-understood. Reports suggest that DHA activates opioid signaling, but there is no information on this from a model of neuropathic pain. As a result, the aims of this study were (1) to determine the antihyperalgesic and antiallodynic effect of peripheral DHA administration, and (2) to evaluate the participation of the opioid receptors in the antihyperalgesic effect of DHA on streptozotocin-induced neuropathic pain in the rat. Female Wistar rats were injected with streptozotocin (50 mg/kg, i.p.) to induce hyperglycemia. The formalin, Hargreaves, and von Frey filaments tests were used to assess the nociceptive activity. Intraplantar administration of DHA (100-1000 μg/paw) or gabapentin (562-1778 μg/paw) decreased formalin-evoked hyperalgesia in diabetic rats, in a dose-dependent manner. Furthermore, DHA (562 μg/paw) and gabapentin (1000 μg/paw) reduced thermal hyperalgesia and allodynia. Local peripheral administration of naloxone (non-selective opioid receptor antagonist; 100 μg/paw), naltrindole (selective δ receptor antagonist; 1 μg/paw), and CTOP (D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2, μ receptor antagonist; 20 μg/paw) prevented formalin-evoked hyperalgesia in diabetic rats but not by GNTI (guanidinonaltrindole, κ receptor antagonist;1 µg/paw). It is suggested that peripheral DHA shows an antihyperalgesic effect in neuropathic pain in the rat. Furthermore, δ and μ receptors are involved in the antihyperalgesic peripheral effect of DHA in diabetic rats.

Synergistic interaction between docosahexaenoic acid and diclofenac on inflammation, nociception, and gastric security models in rats

Preclinical Research & Development The addition of polyunsaturated fatty acids to nonsteroidal anti-inflammatory drugs can increase their antinociceptive activity and produce a gastroprotective effect. The aim of the present study was to examine the effects of the interaction between docosahexaenoic acid (DHA) and diclofenac on inflammation (fixed ratios 1:1, 1:3, and 3:1), nociception (fixed ratio 1:3), and gastric injury in rats. DHA, diclofenac, or combinations of DHA and diclofenac produced anti-inflammatory and antinociceptive effects in rat. The administration of diclofenac produced significant gastric damage, but this effect was not observed with either DHA or the DHA-diclofenac combinations. Effective dose (ED₃₀ ) values were estimated for each individual drug and analyzed isobolographically. The anti-inflammatory experimental ED₃₀ values were 6.97 mg/kg (1:1 fixed ratio), 1.1 mg/kg (1:3 fixed ratio), and 11.34 mg/kg (3:1 fixed ratio). These values were significantly lower (p < .05) than the theoretical ED₃₀ values: 67.94 mg/kg (1:1), 35.37 mg/kg (1:3), and 100.51 mg/kg (3:1). The antinociceptive experimental value was 1.25 mg/kg (1:3 fixed ratio). This value was lower (p < .05) than the theoretical ED₃₀ , which was predicted to be 15.92 mg/kg. These data indicate that the DHA-diclofenac combinations interact at the systemic level, produce minor gastric damage, and potentially have therapeutic advantages for the clinical treatment of inflammatory pain.

Tissue distribution and dermal drug determination of indomethacin transdermal-absorption patches

The tissue distribution and percutaneous drug absorption of indomethacin (IND) patches were studied using commercial IND as a comparison. The concentration of IND in skin, plasma, and muscle in mice was measured by LC-MS/MS, and the IND concentration in the dermis of rats was also monitored by microdialysis. After percutaneous administration, the "double-peak" phenomenon occurred in different tissues, and the IND concentration was ranked as skin first, followed by plasma and then muscle. In particular, skin acted as a reservoir for drug release, and the "secondary hump" in tissue distribution was attributed to the subsequent release of lipophilic IND in skin. It was concluded that examination of the tissue distribution and application of a microdialysis technique provided an effective means of evaluating indomethacin pharmacokinetics.

Bio-active nanoemulsions enriched with gold nanoparticle, marigold extracts and lipoic acid: In vitro investigations

A novel and efficient approach for the preparation of enriched herbal formulations was described and their potential applications including wound healing and antioxidant activity (cell based and cell free) were investigated via in vitro cell culture studies. Nigella sativa oil was enriched with Calendula officinalis extract and lipoic acid capped gold nanoparticles (AuNP-LA) using nanoemulsion systems. The combination of these bio-active compounds was used to design oil in water (O/W) and water in oil (W/O) emulsions. The resulted emulsions were characterized by particle size measurements. The phenolic content of each nanoemulsion was examined by using both colorimetric assay and chromatographic analyses. Two different methods containing cell free chemical assay (1-diphenyl-2-picrylhydrazyl method) and cell based antioxidant activity test were used to evaluate the antioxidant capacities. In order to investigate the bio-activities of the herbal formulations, in vitro cell culture experiments, including cytotoxicity, scratch assay, antioxidant activity and cell proliferation were carried out using Vero cell line as a model cell line. Furthermore, to monitor localization of the nanoemulsions after application of the cell culture, the cell images were monitored via fluorescence microscope after FITC labeling. All data confirmed that the enriched N. sativa formulations exhibited better antioxidant and wound healing activity than N. sativa emulsion without any enrichment. In conclusion, the incorporation of AuNP-LA and C. officinalis extract into the N. sativa emulsions significantly increased the bio-activities. The present work may support further studies about using the other bio-active agents for the enrichment of herbal preparations to strengthen their activities.