Nicorandil inhibits neutrophil recruitment in carrageenan-induced experimental pleurisy in mice

Therapeutic potential of nicorandil beyond anti-anginal drug: A review on current and future perspectives

Nicorandil (NIC) is a well-known anti-anginal agent, which has been recommended as one of the second-line treatments for chronic stable angina as justified by the European guidelines. It shows an efficacy equivalent to that of classic anti-anginal agents. NIC has also been used clinically in various cardiovascular diseases such as variant or unstable angina and reperfusion-induced damage following coronary angioplasty or thrombolysis. Different mechanisms have been involved in the protective effects of nicorandil in various diseases, including opening of adenosine triphosphate-sensitive potassium (KATP) channel and donation of nitric oxide (NO). In recent years, NIC has been found to show numerous pharmacological activities such as neuroprotective, nephroprotective, hepatoprotective, cardioprotective, and testicular protective effects, among other beneficial effects on the body. The present review dwells on the pharmacological potentials of NIC beyond its anti-anginal action.

Role of Gasotransmitters in Inflammatory Edema

Significance: Nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S) are, to date, the identified members of the gasotransmitter family, which consists of gaseous signaling molecules that play central roles in the regulation of a wide variety of physiological and pathophysiological processes, including inflammatory edema. Recent Advances: Recent studies show the potential anti-inflammatory and antiedematogenic effects of NO-, CO-, and H2S-donors in vivo. In general, it has been observed that the therapeutical effects of NO-donors are more relevant when administered at low doses at the onset of the inflammatory process. Regarding CO-donors, their antiedematogenic effects are mainly associated with inhibition of proinflammatory mediators (such as inducible NO synthase [iNOS]-derived NO), and the observed protective effects of H2S-donors seem to be mediated by reducing some proinflammatory enzyme activities. Critical Issues: The most recent investigations focus on the interactions among the gasotransmitters under different pathophysiological conditions. However, the biochemical/pharmacological nature of these interactions is neither general nor fully understood, although specifically dependent on the site where the inflammatory edema occurs. Future Directions: Considering the nature of the involved mechanisms, a deeper knowledge of the interactions among the gasotransmitters is mandatory. In addition, the development of new pharmacological tools, either donors or synthesis inhibitors of the three gasotransmitters, will certainly aid the basic investigations and open new strategies for the therapeutic treatment of inflammatory edema. Antioxid. Redox Signal. 40, 272-291.

Anti-Inflammatory Activity of N'-(3-(1H-indol-3-yl)benzylidene)-2-cyanoacetohydrazide Derivative via sGC-NO/Cytokine Pathway

The N-acylhydrazone function has been reported as a pharmacophore group of molecules with diverse pharmacological activities, including anti-inflammatory effects. Therefore, this study was designed to evaluate the anti-inflammatory potential of the compound N'-(3-(1H-indol-3-yl)benzylidene)-2-cyanoacetohydrazide (JR19) in vivo. The study started with the carrageenan-induced peritonitis model, followed by an investigation of leukocyte migration using the subcutaneous air pouch test and an assessment of the antinociceptive profile using formalin-induced pain. A preliminary molecular docking study focusing on the crystallographic structures of NFκB, iNOS, and sGC was performed to determine the likely mechanism of action. The computational study revealed satisfactory interaction energies with the selected targets, and the same peritonitis model was used to validate the involvement of the nitric oxide pathway and cytokine expression in the peritoneal exudate of mice pretreated with L-NAME or methylene blue. In the peritonitis assay, JR19 (10 and 20 mg/kg) reduced leukocyte migration by 59% and 52%, respectively, compared to the vehicle group, with the 10 mg/kg dose used in subsequent assays. In the subcutaneous air pouch assay, the reduction in cell migration was 66%, and the response to intraplantar formalin was reduced by 39%, particularly during the inflammatory phase, suggesting that the compound lacks central analgesic activity. In addition, a reversal of the anti-inflammatory effect was observed in mice pretreated with L-NAME or methylene blue, indicating the involvement of iNOS and sGC in the anti-inflammatory response of JR19. The compound effectively and significantly decreased the levels of IL-6, TNF-α, IL-17, and IFN-γ, and this effect was reversed in animals pretreated with L-NAME, supporting a NO-dependent anti-inflammatory effect. In contrast, pretreatment with methylene blue only reversed the reduction in TNF-α levels. Therefore, these results demonstrate the pharmacological potential of the novel N-acylhydrazone derivative, which acts through the nitric oxide pathway and cytokine signaling, making it a strong candidate as an anti-inflammatory and immunomodulatory agent.

Nicorandil/ morphine crosstalk accounts for antinociception and hepatoprotection in hepatic fibrosis in rats: Distinct roles of opioid/cGMP and NO/KATP pathways

Previous report indicated that nicorandil potentiated morphine antinociception and attenuated hepatic injury in liver fibrotic rats. Herein, the underlying mechanisms of nicorandil/morphine interaction were investigated using pharmacological, biochemical, histopathological, and molecular docking studies. Male Wistar rats were injected intraperitoneally (i.p.) with carbon tetrachloride (CCl4, 40%, 2 ml/kg) twice weekly for 5 weeks to induce hepatic fibrosis. Nicorandil (15 mg/kg/day) was administered per os (p.o.) for 14 days in presence of the blockers; glibenclamide (KATP channel blocker, 5 mg/kg, p.o.), L-NG-nitro-arginine methyl ester (L-NAME, nitric oxide synthase inhibitor, 15 mg/kg, p.o.), methylene blue (MB, guanylyl cyclase inhibitor, 2 mg/kg, i.p.) and naltrexone (opioid antagonist, 20 mg/kg, i.p.). At the end of the 5th week, analgesia was evaluated using tail flick and formalin tests along with biochemical determinations of liver function tests, oxidative stress markers and histopathological examination of liver tissues. Naltrexone and MB inhibited the antinociceptive activity of the combination. Furthermore, combined nicorandil/morphine regimen attenuated the release of endogenous peptides. Docking studies revealed a possible interaction of nicorandil on µ, κ and δ opioid receptors. Nicorandil/morphine combination protected against liver damage as evident by decreased liver enzymes, liver index, hyaluronic acid, lipid peroxidation, fibrotic insults, and increased superoxide dismutase activity. Nicorandil/morphine hepatoprotection and antioxidant activity were inhibited by glibenclamide and L-NAME but not by naltrexone or MB. These findings implicate opioid activation/cGMP versus NO/KATP channels in the augmented antinociception, and hepatoprotection, respectively, of the combined therapy and implicate provoked cross talk by nicorandil and morphine on opioid receptors and cGMP signaling pathway. That said, nicorandil/morphine combination provides a potential multitargeted therapy to alleviate pain and preserve liver function.

Nicorandil reduces morphine withdrawal symptoms, potentiates morphine antinociception, and ameliorates liver fibrosis in rats

AIMS

Chronic liver disease (CLD) is a serious medical condition affecting patients globally and pain management poses a unique challenge. ATP-sensitive potassium channels (K_ATP) are expressed in nociceptive neurons and hepatic cells. We tested the hypothesis whether morphine and nicorandil, K_ATP channel opener, alone and in combination possess hepatoprotective, antinociceptive effect and alter morphine physical dependence.

MAIN METHODS

Intraperitoneal injection (i.p.) of carbon tetrachloride (CCl₄) induced liver fibrosis in male Wistar rats. Nicorandil (15 mg/kg/day) was administered per os for two weeks. Morphine (3.8, 5, 10 mg/kg, i.p.) was administered prior to antinociception testing in tail flick and formalin tests. Morphine physical dependence following naloxone injection, fibrotic, oxidative stress markers, and liver histopathology were assessed.

KEY FINDINGS

Morphine alone, produced insignificant changes of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), hepatic hydroxyproline (Hyp), malondialdehyde (MDA), and superoxide dismutase (SOD) levels and exerted significant antinociception in the pain models. Nicorandil alone protected against liver damage (decreased serum ALT, AST, HA, hepatic Hyp, MDA, increased SOD levels, improved fibrosis scores). Nicorandil/morphine combination produced remarkable hepatoprotection and persistent analgesia compared to morphine alone as evidenced by reduced (EC50) of morphine. Nicorandil augmented morphine analgesia and markedly decreased withdrawal signs in morphine-dependent rats.

SIGNIFICANCE

The data showed for the first time, the hepatoprotection and augmented antinociception mediated by nicorandil/morphine combination in liver fibrosis via antioxidant and antifibrotic mechanisms. Nicorandil ameliorated withdrawal signs in morphine dependence in CLD. Thus, combining nicorandil/morphine provides a novel treatment strategy to ameliorate hepatic injury, potentiate antinociception and overcome morphine-induced physical dependence in liver fibrosis.

Hepatoprotective effect of nicorandil against acetaminophen-induced oxidative stress and hepatotoxicity in mice via modulating NO synthesis

Acetaminophen (APAP) overdose can produce hepatotoxicity and consequently liver damage. This study investigated the hepatoprotective impacts of nicorandil on hepatic damage induced by APAP. Nicorandil was administered orally (100 mg/kg) for seven days before APAP challenge (500 mg/kg, ip). Pretreatment with nicorandil reduced serum levels of aminotransferases, bilirubin, GGT and LDH, and increased serum level of albumin. Moreover, nicorandil inhibited the increase in liver MDA levels and reversed the decline in GSH content and SOD activity. Besides, it notably alleviated APAP-induced necrosis observed in histopathological findings. Additionally, nicorandil alleviated APAP-induced NO overproduction and iNOS expression; however, the protein expression of eNOS was significantly increased. Moreover, nicorandil markedly reduced hepatic TNF-α and NF-κB levels, in addition to decreasing the protein expression of MPO in hepatic tissues. Furthermore, flow cytometry (annexin V-FITC/PI) displayed a significant decline in late apoptotic and necrotic cells, and an increase in viable cells in nicorandil group. Also, nicorandil caused a significant boost in hepatic antiapoptotic marker bcl-2 level. The presented data proposed that the protective effect of nicorandil might be attributed to its antioxidant, its impact on NO homeostasis, and its anti-inflammatory properties. Therefore, nicorandil may be a promising candidate for protection from liver injury induced by APAP.

The Essential Oil of Hyptis crenata Inhibits the Increase in Secretion of Inflammatory Mediators

Background: Hyptis crenata is a plant of great ethnopharmacological importance widely distributed in South American countries. In Northeast Brazil, teas or infusions of its aerial parts are used in folk medicine to treat several acute and chronic inflammatory diseases. In a previous work we have demonstrated that the essential oil of H. crenata (EOHc) has an antiedematogenic effect. The aim of this work was to evaluate the effect of EOHc on cytokines secretion and cellular infiltration. Methods: Peritonitis and paw edema models induced by carrageenan were used to determine leucocyte count, myeloperoxidase (MPO) activity, nitrite, and cytokines secretion. Results: EOHc (10−300 mg/kg) significantly inhibited leucocyte migration and reduced the neutrophil count (control: 1.46 × 103 ± 0.031 × 103/mL) of the total leucocytes population in extracellular exudate (control: 2.14 × 103 ± 0.149 × 103/mL) by 15.00%, 43.29%, 65.52%, and 72.83% for the doses of 10, 30, 100, and 300 mg/kg EOHc, respectively (EC50: 24.15 mg/kg). EOHc (100 mg/kg) inhibited the increase in myeloperoxidase activity and completely blocked the increase in nitrite concentration induced by carrageenan. EOHc markedly reduced the pro-inflammatory cytokines (IL-6, MCP-1, IFN-γ, TNF-α, and IL-12p70) and increased IL-10, an anti-inflammatory cytokine (compared to control group, p < 0.05). Conclusions: This study demonstrates that EOHc has a long-lasting anti-inflammatory effect mediated through interference on MPO activity, and nitrite, and cytokines secretion. This effect, coupled with low EOHc toxicity, as far as results obtained in mice could be translated to humans, suggests that EOHc has great potentiality as a therapeutic agent.

Metformin effect in models of inflammation is associated with activation of ATP-dependent potassium channels and inhibition of tumor necrosis factor-α production

Metformin is an oral hypoglycemic drug widely used in the management of type 2 diabetes mellitus. We have recently demonstrated that metformin exhibits activity in models of nociceptive and neuropathic pain. However, little is known about its effects in experimental models of inflammation and inflammatory pain. Thus, the present study aimed to evaluate the activity of metformin in experimental models of inflammation and inflammatory pain in mice, as well as the underlying mechanisms. Previous (1 h) per os (p.o.) administration of metformin (250, 500 or 1000 mg/kg) inhibited the mechanical allodynia and paw edema induced by intraplantar (i.pl.) injection of carrageenan (600 μg) and also the pleurisy induced by this stimulus (200 μg, intrapleural). In the model of mechanical allodynia and paw edema induced by carrageenan, metformin also exhibited activity when administered after (1 h) the inflammatory stimulus. Metformin (1000 mg/kg) reduced the production of tumor necrosis factor-α induced by i.pl. injection of carrageenan. Metformin antiallodynic effect was not affected by previous administration of naltrexone (5 or 10 mg/kg, intraperitoneal) or cyproheptadine (5 or 10 mg/kg, p.o). However, this effect was abolished by previous administration of glibenclamide (20 or 40 mg/kg, p.o). In conclusion, the results demonstrate the activity of metformin in models of inflammation and inflammatory pain. In addition, the results indicate that the activity of metformin may be mediated by activation of ATP-sensitive potassium channels and reduction of production of inflammatory mediators. Altogether, these results stimulate the conduction of studies aiming to evaluate whether metformin may be repositioned in the treatment of patients with painful and inflammatory disorders.

The role of nitric oxide in pleural disease

Nitric oxide (NO) regulates various physiological and pathophysiological functions in the lungs. However, there is much less information about the effects of NO in the pleura. The present review aimed to explore the available evidence regarding the role of NO in pleural disease. NO, has a double-edged role in the pleural cavity. It is an essential signaling molecule mediating various physiological cell functions such as lymphatic drainage of the serous cavities, the immune response to intracellular multiplication of pathogens, and downregulation of neutrophil migration, but also induces genocytotoxic and mutagenic effects when present in excess. NO is implicated in the pathogenesis of asbestos-related or exudative pleural disease and mesothelioma. From a clinical point of view, the fraction of exhaled NO has been suggested as a potential non-invasive tool for the diagnosis of benign asbestos-related disorders. Under experimental conditions, NO-mimetics were found to attenuate hypoxia-induced therapy resistance in mesothelioma. Similarly, hybrid agents consisting of an NO donor coupled with a parent anti-inflammatory drug showed an enhancement of the anti-inflammatory activity of anti-inflammatory drugs. However, given the paucity of research work performed over the last years in this area, further research should be undertaken to establish reliable conclusions with respect to the feasibility of determining or targeting the NO signaling pathway for pleural disease diagnosis and therapeutic management.

Electrochemical evidence of nitrate release from the nitrooxy compound 4-((nitrooxy) methyl)-3-nitrobenzoic acid and its antinociceptive and anti-inflammatory activities in mice

Considering the many biological activities of nitric oxide (NO), some lines of research focused on the modulation of these activities through the provision of this mediator by designing and synthesizing compounds coupled with an NO donor group. Thus, the objectives of the present study were to carry out an electrochemical investigation of the nitrooxy compound 4-((nitrooxy) methyl)-3-nitrobenzoic acid (1) and evaluate its activities and putative mechanisms in experimental models of pain and inflammation. Voltammetric studies performed in aprotic medium (mimetic of membranes) showed important electrochemical reduction mechanisms: nitroaromatic reduction, self-protonation, and finally reductive elimination, which leads to nitrate release. Systemic administration of the nitrooxy compound (1) inhibited the nociceptive response induced by heat and the tactile hypersensitivity and paw edema induced by carrageenan in mice. The activities in the models of inflammatory pain and edema were associated with reduced neutrophil recruitment and production of inflammatory cytokines, such as interleukin (IL)-1β, IL-6, tumor necrosis factor-α and CXCL-1, and increased production of IL-10. Concluding, electrochemical analysis revealed unequivocally that electron transfer at the nitro group of the nitrooxy compound (1) results in the cleavage of the organic nitrate, potentially resulting in the generation of NO. This electrochemical mechanism may be compared to a biochemical electron-transfer mediated nitrate release that, by appropriate in vivo bioreduction (enzymatic or not) would lead to NO production. Compound (1) exhibits activities in models of inflammatory pain and edema that may be due to reduced recruitment of neutrophils and production of inflammatory cytokines and increased production of IL-10. These results reinforce the interest in the investigation of NO donor compounds as candidates for analgesic and anti-inflammatory drugs.

Anti-inflammatory and antinociceptive activity profile of a new lead compound - LQFM219

LQFM219 is a molecule designed from celecoxibe (COX-2 inhibitor) and darbufelone (inhibitor of COX-2 and 5-LOX) lead compounds through a molecular hybridisation strategy. Therefore, this work aimed to investigate the antinociceptive and anti-inflammatory activities of this new hybrid compound. The acute oral systemic toxicity of LQFM219 was evaluated via the neutral red uptake assay. Acetic acid-induced abdominal writhing and CFA-induced mechanical hyperalgesia were performed to evaluate the antinociceptive activity, and the anti-oedematogenic activity was studied by CFA-induced paw oedema and croton oil-induced ear oedema. Moreover, the acute anti-inflammatory activity was determined by carrageenan-induced pleurisy. In addition, cell migration, myeloperoxidase enzyme activity, and TNF-α and IL-1β levels were determined in pleural exudate. Moreover, a redox assay was conducted using electroanalytical and DPPH methods. The results demonstrated that LQFM219 was classified as GHS category 4, and it showed better free radical scavenger activity compared to BHT. Besides, LQFM219 decreased the number of writhings induced by acetic acid and the response to the mechanical stimulus in the CFA-induced mechanical hyperalgesia test. Furthermore, LQFM219 reduced oedema formation, cell migration, and IL-1β and TNF-α levels in the pleural cavity and inhibited myeloperoxidase enzyme activity. Thus, our study provides that the new pyrazole derivative, LQFM219, demonstrated low toxicity, antinociceptive and anti-inflammatory potential in vitro and in vivo.

Albizia anthelmintica: HPLC-MS/MS profiling and in vivo anti-inflammatory, pain killing and antipyretic activities of its leaf extract

In the current work, the phytochemical composition of a leaf methanol extract from Albizia anthelmintica was thoroughly investigated. The antioxidant, anti-inflammatory, analgesic, and antipyretic activities of the extract were investigated. In the carrageenan induced hind paw edema bioassay; the extract significantly reduced the edema thickness in rats and diminished the leukocyte migration to the peritoneal cavity in mice. The extract exhibited central and peripheral anti-nociceptive effects; it significantly decreased the number of acetic acid induced writhes and prolonged the latency time in the hot plate test. The extract showed a substantial antipyretic activity as it decreased significantly the elevated rectal temperature in mice after intraperitoneal injection of Brewer's yeast. Molecular docking of some major compounds in the extract to COX-1, COX-2 and 5-LOX, enzymes involved in the inflammation cascade, revealed appreciable interactions with the conserved amino acid residues in these target proteins. These findings were confirmed with in vitro enzyme inhibitory assays in which the extract showed IC₅₀ values of 4.11, 0.054, and 1.74 μg/mL towards COX-1, COX-2 and 5-LOX, respectively. The extract displayed solid antioxidant properties as well with a TAC value of 35.13 U/L and EC₅₀of 5.36 μg/mL in DPPH assay. These findings suggested that Albizia anthelmintica is a good antioxidant with potential therapeutic efficacy for treating inflammation, pain and related oxidative stress disorders.

Nicorandil Attenuates LPS-Induced Acute Lung Injury by Pulmonary Endothelial Cell Protection via NF-κB and MAPK Pathways

Acute lung injury (ALI) is a devastating critical disease characterized by diffuse inflammation and endothelial dysfunction. Increasing evidence, including from our laboratory, has revealed that the opening of ATP-sensitive potassium (K_ATP) channels has promising anti-inflammation and endothelial protection activities in various disorders. However, the impacts of K_ATP channels on ALI remain obscure. In this study, we used nicorandil (Nico), a classic K_ATP channel opener, to investigate whether opening of K_ATP channels could alleviate ALI with an emphasis on human pulmonary artery endothelial cell (HPAEC) modulation. The results showed that Nico inhibited lipopolysaccharide- (LPS-) induced inflammatory response, protein accumulation, myeloperoxidase activity, and endothelial injury. In vitro, Nico reduced LPS-induced HPAEC apoptosis and the expression of cleaved-caspase-3, caspase-9, and CCAAT/enhancer-binding protein homologous protein (CHOP). Additionally, Nico inhibited inflammation by suppressing monocyte-endothelial adhesion and decreasing the expression of proinflammatory proteins. Moreover, Nico restored the expression and the distribution of adherens junction vascular endothelial- (VE-) cadherin. Further, Nico abolished the increase in intracellular reactive oxygen species (ROS) and the activation of NF-κB and mitogen-activated protein kinase (MAPK) in HPAECs. Glibenclamide (Gli), a nonselective K_ATP channel blocker, abrogated the effects of Nico, implying that opening of K_ATP channels contributes to the relief of ALI. Together, our findings indicated that Nico alleviated LPS-induced ALI by protecting ECs function via preventing apoptosis, suppressing endothelial inflammation and reducing oxidative stress, which may be attributed to the inhibition of NF-κB and MAPK signaling pathways.

Nicorandil abates arthritic perturbations induced by complete Freund's adjuvant in rats via conquering TLR4-MyD88-TRAF6 signaling pathway

BACKGROUND AND PURPOSE

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune inflammatory disease which poses a need to explore effective yet safe pharmacotherapeutic options. The current work aimed to study the therapeutic role of nicorandil in controlling RA.

EXPERIMENTAL APPROACH

Complete Freund's adjuvant (CFA)-induced arthritis model was applied by injecting 400 μL of CFA in the right hind paw at day 0 and day 7. Four groups of rats were used as follows: normal-control (CTRL), CFA-induced arthritis (ART), CFA-induced arthritis treated with diclofenac (DIC) and CFA-induced arthritis treated with nicorandil (NIC). Both NIC and DIC were administered at day 14 for two weeks. Paw volume, knee joint diameter, pain behavior assessment as well as body weight were all periodically recorded throughout the experimental period. Following the sacrifice of animals at day 28, gene expressions of TLR-4, MyD88 and TRAF6 as well as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), nuclear factor Kappa B (NF-κB) were quantified in hind paws tissue. Finally, the serum levels of the inflammatory biomarkers (tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) together with the histopathological examination of sections in the rat hind paw were recorded.

RESULTS

Both NIC and DIC proved promising anti-arthritic potential mediated, at least in part through switching off TLR4-MyD88-TRAF6 axis as well as downstream TRAF6 dependent activated MAP kinases and NF-κB.

CONCLUSION AND IMPLICATIONS

Nicorandil, via interfering with TLR4 signaling, sheds light on a potential clinical role of the drug in pursuit for safe and effective regimens for RA.

Nicorandil ameliorates pulmonary inflammation and fibrosis in a rat model of silicosis

Nicorandil, an antianginal and potassium channel opener agent, has different useful impacts on cardiovascular and respiratory systems. Its effect against silicosis has not been discussed yet, therefore, this is an attempt to decide whether nicorandil can reduce silica-induced lung injury in rats. Silica model was induced by intranasal instillation of silica dust once. Rats were given nicorandil for 56 days after exposure to silica. Results showed that nicorandil significantly alleviated silica-induced inflammation as it decreased the elevated levels of total and differential cell counts, pulmonary edema (revealed by decreased lung/body weight ratio and W/D weight ratio), LDH and total protein levels in BALF. Notably, nicorandil decreased collagen deposition as evidenced by reduction in levels of hydroxyproline and collagen in lung tissues as well as obvious alleviation in silica-induced fibrosis in histopathological findings. Nicorandil effectively reduced the increased expression of NF-κB and iNOS and decreased MPO levels in lung tissues. Moreover, nicorandil abolished oxidative and nitrosative stress via reducing levels of pulmonary MDA and NOx concomitant with elevating levels of pulmonary GSH and SOD. Meanwhile, nicorandil decreased the levels of TNF-α and TGF-β, up regulated Nrf-2 and HO-1 levels in BALF suggesting antioxidant, anti-inflammatory and antifibrotic properties. In summary, nicorandil can confer protection against silica-induced lung inflammation and fibrosis. This impact might be due to its ability to down regulate the production of inflammatory and fibrotic cytokines in addition to restoring oxidant/antioxidant balance.

Antipleuritic and Vascular Permeability Inhibition of the Ethyl Acetate-Petroleum Ether Stem Bark Extract of Maerua angolensis DC (Capparaceae) in Murine

Maerua angolensis has been used traditionally in the management of pain, arthritis, and rheumatism in Ghana and Nigeria but no scientific evidence is currently available to give credence to its folkloric use. The aim of this study was therefore to evaluate the anti-inflammatory effects of a stem bark extract of Maerua angolensis DC (MAE) in acute inflammatory models. The effects of MAE (30-300 mg kg⁻¹) on neutrophil infiltration, exudate volume, and endogenous antioxidant enzymes in lung tissues and lung morphology were evaluated with the carrageenan induced pleurisy model in Sprague Dawley rats. The effects of MAE (30-300 mg kg⁻¹) on vascular permeability were also evaluated in the acetic acid induced vascular permeability in ICR mice. MAE significantly reduced neutrophil infiltration, exudate volume, and lung tissue damage in carrageenan induced pleurisy. MAE increased the activities of antioxidant enzymes glutathione, superoxide dismutase, and catalase in lung tissues. The extract was also able to reduce myeloperoxidase activity and lipid peroxidation in lung tissues in carrageenan induced rat pleurisy. Vascular permeability was also attenuated by the extract with marked reduction of Evans blue dye leakage in acetic acid induced permeability assay. The results indicated that Maerua angolensis is effective in ameliorating inflammation induced by carrageenan and acetic acid. It also has the potential of increasing the activity of endogenous antioxidant enzymes.

Correction of morphofunctional disturbances arising when modelling Preeclampsia with resveratrol and nicorandil

Introduction: Preeclampsia is one of the most serious diseases of the second half of pregnancy and is surely amongst the top three causes of maternal mortality. Therefore, the creation of new drugs for preventing and correcting preeclampsia is an urgent task.

Methods: In the experiment, an ADMA-like L-NAME-induced model of preeclampsia was reproduced. To assess the emerging morphofunctional disorders, the following parameters were used: blood pressure, endothelial dysfunction coefficient, microcirculation in the placenta, proteinuria, fluid content in the large omentum, concentration of terminal metabolites in the blood plasma, morphological state of the placenta and kidneys and morphometric parameters of the foetus.

Results and Discussion: Injection of L-NAME into the animals from the 14th to the 20th day of pregnancy causes disorders: an increase in systolic and diastolic blood pressure by 1.4 and 1.5 times, an increase in proteinuria by 3.3 times and an increase in the fluid content in a large omentum from 45.82 ± 1.82% to 54.73 ± 1.96%, which correspond to disorders due to preeclampsia in pregnant women. There was also a disturbance of endothelial function, as evidenced by an increase in the coefficient of endothelial dysfunction (CED) by 2.9 times. The use of resveratrol leads to a pronounced correction in the changes that occur: a decrease in systolic and diastolic arterial pressure by 1.2 and 1.3 times, a decrease in proteinuria by a factor of 1.9 and a decrease in the fluid content in the large omentum to 50.00 ± 1.25%. The use of nicorandil leads to a pronounced correction in the resulting changes: a decrease in the diastolic blood pressure by 1.14 times, a decrease in proteinuria by a factor of 1.7 and a decrease in the fluid content in the large omentum to 50.57 ± 2.08%. CED decreased 1.7 times. When combining their use with amlodipine, the positive effects increased: systolic and diastolic blood pressure decreased 1.13 and 1.24 times and 1.14 and 1.23 times, respectively, proteinuria decreased 2.7 and 2.3 times, the fluid content in the large omentum was reduced to 44.54 ± 1.80% and 46.73 ± 1.30%. CED decreased 1.7 and 2.3 times. The administration of glibenclamide together with resveratrol and nicorandil removes a significant part of their positive effects.

Conclusion: Resveratrol and nicorandil have a significant positive effect in the correction of morphofunctional disorders in animals with ADMA-like preeclampsia. Activation of K+ATP channels plays a significant role in the realisation of their positive effects.

Nicorandil and theophylline can protect experimental rats against complete Freund's adjuvant-induced rheumatoid arthritis through modulation of JAK/STAT/RANKL signaling pathway

Signaling pathways are interesting fields of study of pathogenesis and treatment trials. We elucidated the possible protective effects of nicorandil (15mg/kg/day) and theophylline (20mg/kg/day) on experimentally-induced RA, focusing on the role of JAK (Janus Kinase) / STAT (Signal Transducer and Activator of Transcription) / RANKL (Receptor Activator of Nuclear factor-Kappa B Ligand) / cytokine signaling pathway. Four sets of experiments were performed. First, effect of test agents on normal animals was evaluated. Second, effect of test agents was evaluated on Complete Freund's Adjuvant (CFA; 0.3ml, s.c.)-induced RA to investigate anti-arthritic effect. Third, effect of test agents was evaluated on growth hormone (GH; 2mg/kg/day, s.c.)-induced stimulation of JAK/STAT/RANKL/cytokine signaling pathway to investigate the role of this signaling pathway in their anti-arthritic effect. Fourth, the effect of test agents was performed on CFA/GH-induced RA. To fulfill this purpose, serum anti-citrullinated peptide antibody (ACPA), interleukin-6 (IL-6), and cartilage oligomeric matrix protein (COMP), together with tissue JAK2, STAT3, RANKL, inducible and endothelial nitric oxide synthases (iNOS and eNOS) as well as macrophage inflammatory protein (MIP_1α) were estimated using ELISA, Western blotting and PCR techniques, confirmed by a histopathological study. Test agents significantly corrected JAK2, STAT3, RANKL and IL-6 values in animals receiving GH. Additionally, test agents could correct ACPA, IL-6, COMP, JAK2, STAT3, RANKL, iNOS, eNOS and MIP_1α levels compared with the respective CFA or CFA/GH controls. These results conclude that nicorandil and theophylline have good anti-arthritic effects related to modulation of JAK/STAT/RANKL signaling pathway. Further clinical trials are claimed.