Electroacupuncture alleviates the relapse of pain-related aversive memory by activating KOR and inhibiting GABAergic neurons in the insular cortex.

Pain-related aversive memory is common in chronic pain patients. Electroacupuncture has been demonstrated to block pain-related aversive memory. The insular cortex is a key region closely related to aversive behaviors. In our study, a potential mechanism underlying the effect of electroacupuncture treatment on pain-related aversive memory behaviors relative to the insular cortex was investigated. Our study used the chemogenetic method, pharmacological method, electroacupuncture intervention, and behavioral detection. Our study showed that both inhibition of gamma-aminobutyric acidergic neurons and activation of the kappa opioid receptor in the insular cortex blocked the pain-related aversive memory behaviors induced by 2 crossover injections of carrageenan in mice; conversely, both the activation of gamma-aminobutyric acidergic neurons and inhibition of kappa opioid receptor in the insular cortex play similar roles in inducing pain-related aversive memory behaviors following 2 crossover injections of carrageenan. In addition, activation of gamma-aminobutyric acidergic neurons in the insular cortex reversed the effect of kappa opioid receptor activation in the insular cortex. Moreover, electroacupuncture effectively blocked pain-related aversive memory behaviors in model mice, which was reversed by both activation of gamma-aminobutyric acidergic neurons and inhibition of kappa opioid receptor in the insular cortex. The effect of electroacupuncture on blocking pain-related aversive memory behaviors may be related to the activation of the kappa opioid receptor and inhibition of gamma-aminobutyric acidergic neurons in the insular cortex.

Evaluation of the Antioxidant and Anti-Inflammatory Activities and Acute Toxicity of Caco Seed (Chrysobalanus icaco L.) in Murine Models.

Chysobalanus icaco L. (C. icaco) is a plant that is native to tropical America and Africa. It is also found in the southeast region of Mexico, where it is used as food and to treat certain diseases. This study aimed to carry out a phytochemical analysis of an aqueous extract of C. icaco seed (AECS), including its total phenol content (TPC), total flavonoid content (TFC), and condensed tannins (CT). It also aimed to examine the antioxidant and metal-ion-reducing potential of the AECS in vitro, as well as its toxicity and anti-inflammatory effect in mice. Antioxidant and metal-ion-reducing potential was examined by inhibiting DPPH, ABTS, and FRAP. The acute toxicity test involved a single administration of different doses of the AECS (0.5, 1, and 2 g/kg body weight). Finally, a single administration at doses of 150, 300, and 600 mg/kg of the AECS was used in the carrageenan-induced model of subplantar acute edema. The results showed that the AECS contained 124.14 ± 0.32 mg GAE, 1.65 ± 0.02 mg EQ, and 0.910 ± 0.01 mg of catechin equivalents/g dried extract (mg EC/g de extract) for TPC, TFC and CT, respectively. In the antioxidant potential assays, the values of the median inhibition concentration (IC50) of the AECS were determined with DPPH (0.050 mg/mL), ABTS (0.074 mg/mL), and FRAP (0.49 mg/mL). Acute toxicity testing of the AECS revealed no lethality, with a median lethal dose (LD50) value of >2 g/kg by the intragastric route. Finally, for inhibition of acute edema, the AECS decreased inflammation by 55%, similar to indomethacin (59%, p > 0.05). These results demonstrated that C. icaco seed could be considered a source of bioactive molecules for therapeutic purposes due to its antioxidant potential and anti-inflammatory activity derived from TPC, with no lethal effect from a single intragastric administration in mice.

Stomatin-like protein 3 modulates the responses of Aδ, but not C fiber bone afferent neurons to noxious mechanical stimulation in an animal model of acute experimental bone pain.

STOML3 is a membrane bound scaffolding protein that has been shown to facilitate the opening of mechanically sensitive ion channels and contribute to noxious mechanical sensation, allodynia and hyperalgesia. In this study, we aimed to determine the role of STOML3 in noxious mechanical sensitivity of bone afferent neurons and carrageenan-induced acute inflammation in the bone. An in vivo, electrophysiological bone-nerve preparation was used to make recordings of the activity and sensitivity of bone afferent neurons that innervate the tibial marrow cavity in anaesthetised rats, in response to noxious mechanical stimuli delivered to the marrow cavity, before and after injection of either the STOML3 oligomerisation inhibitor OB-1 or vehicle, in either naïve animals or animals with carrageenan-induced inflammation of the marrow cavity. A dynamic weight-bearing apparatus was used to measure weight bearing in response to inflammatory pain before and after injection of OB-1 or saline into the tibial marrow cavity in the presence of carrageenan-induced inflammation. Electrophysiological recordings revealed that Aδ, but not C bone afferent neurons have a reduced discharge frequency in response to mechanical stimulation, and that carrageenan-induced sensitisation of Aδ, but not C bone afferent neurons was attenuated by inhibition of STOML3 oligomerisation with OB-1. Animals treated with OB-1 spent a significantly greater amount of time on the limb injected with carrageenan than animals treated with saline. Our findings demonstrate that inhibition of STOML3 oligomerisation reduces inflammatory bone pain by reducing the sensitivity of Aδ bone afferent neurons to mechanical stimulation. Targeting STOML3 may be an effective approach to reduce pain from noxious pressure and/or painful inflammatory pathology in bone.

Evidence and hypotheses on adverse effects of the food additives carrageenan (E 407)/processed Eucheuma seaweed (E 407a) and carboxymethylcellulose (E 466) on the intestines: a scoping review.

This scoping review provides an overview of publications reporting adverse effects on the intestines of the food additives carrageenan (CGN) (E 407)/processed Eucheuma seaweed (PES) (E 407a) and carboxymethylcellulose (CMC) (E 466). It includes evidence from human, experimental mammal and in vitro research publications, and other evidence. The databases Medline, Embase, Scopus, Web of Science Core Collection, Cochrane Database of Systematic Reviews and Epistemonikos were searched without time limits, in addition to grey literature. The publications retrieved were screened against predefined criteria. From two literature searches, 2572 records were screened, of which 224 records were included, as well as 38 records from grey literature, making a total of 262 included publications, 196 on CGN and 101 on CMC. These publications were coded and analyzed in Eppi-Reviewer and data gaps presented in interactive maps. For CGN, five, 69 and 33 research publications on humans, experimental mammals and in vitro experiments were found, further separated as degraded or native (non-degraded) CGN. For CMC, three human, 20 animal and 14 in vitro research publications were obtained. The most studied adverse effects on the intestines were for both additives inflammation, the gut microbiome, including fermentation, intestinal permeability, and cancer and metabolic effects, and immune effects for CGN. Further studies should focus on native CGN, in the form and molecular weight used as food additive. For both additives, randomized controlled trials of sufficient power and with realistic dietary exposure levels of single additives, performed in persons of all ages, including potentially vulnerable groups, are needed.

New Insight on the Cytoprotective/Antioxidant Pathway Keap1/Nrf2/HO-1 Modulation by Ulva intestinalis Extract and Its Selenium Nanoparticles in Rats with Carrageenan-Induced Paw Edema.

Currently, there is growing interest in exploring natural bioactive compounds with anti-inflammatory potential to overcome the side effects associated with the well-known synthetic chemicals. Algae are a rich source of bioactive molecules with numerous applications in medicine. Herein, the anti-inflammatory effect of Ulva intestinalis alone or selenium nanoparticles loaded with U. intestinalis (UISeNPs), after being fully characterized analytically, was investigated by a carrageenan-induced inflammation model. The pretreated groups with free U. intestinalis extract (III and IV) and the rats pretreated with UISeNPs (groups V and VI) showed significant increases in the gene expression of Keap1, with fold increases of 1.9, 2.27, 2.4, and 3.32, respectively. Similarly, a remarkable increase in the Nrf2 gene expression, with 2.09-, 2.36-, 2.59-, and 3.7-fold increases, was shown in the same groups, respectively. Additionally, the groups III, IV, V, and VI revealed a significantly increased HO-1 gene expression with a fold increase of 1.48, 1.61, 1.87, and 2.84, respectively. Thus, both U. intestinalis extract and the UISeNPs boost the expression of the cytoprotective/antioxidant pathway Keap1/Nrf2/HO-1, with the UISeNPs having the upper hand over the free extract. In conclusion, U. intestinalis and UISeNPs have proven promising anti-inflammatory activity through mediating different underlying mechanisms.

Modulating Effects of the Hydroethanolic Leaf Extract of Persicaria lanigera R. Br. Soják (Polygonaceae) against Acute Inflammation.

Plant species have been used traditionally to treat numerous inflammatory disorders because of their known medicinal properties. This study aimed to assess the anti-inflammatory effect of aqueous ethanolic leaf extract of Persicaria lanigera using acute inflammatory models. The safety profile of the Persicaria lanigera extract was assessed using an acute toxicity model. The anti-inflammatory effect of the Persicaria lanigera leaf extract (100-600 mg·kg-1, p.o.) was studied in carrageenan-induced paw oedema, zymosan-induced knee joint arthritis, and histamine-induced paw oedema in Sprague-Dawley rats (n = 5). It was observed that the Persicaria lanigera leaf extract administered prophylactically significantly inhibited paw oedema from 99.01 ± 12.59 to 59.10 ± 4.94%, 56.08 ± 3.65%, and 48.62 ± 3.27% at 100 mg·kg-1, 300 mg·kg-1, and 600 mg·kg-1, while the standard drug, aspirin, showed 41.84 ± 9.25% in carrageenan-induced paw oedema, respectively. Furthermore, the extract decreased knee joint inflammation significantly from 62.43 ± 5.73% to 32.07 ± 2.98% and 24.33 ± 8.58% at 300 mg·kg-1 and 600 mg·kg-1 in zymosan-induced knee joint inflammation, respectively. In the histamine-induced paw oedema model, the extract significantly inhibited oedema to 61.53 ± 9.17%, 54.21 ± 9.38%, and 54.22 ± 9.37% at the same doses. Aqueous ethanolic leaf extract of Persicaria lanigera is safe and attenuates inflammation in acute inflammation models.

Targeting Nrf2 and NF-κB Signaling Pathways in Inflammatory Pain: The Role of Polyphenols from Thinned Apples.

Diet can modulate the different stages of inflammation due to the presence of bioactive compounds such as polyphenols. Apples are a great source of phenolic compounds that show anti-inflammatory and antioxidant properties, and these might be used as a dietary supplement and/or functional element in the treatment of chronic inflammatory illnesses. The aim of our study was to evaluate the anti-inflammatory and antioxidant actions of thinned apple polyphenol (TAP) extracts in a model of paw edema. The experimental model was induced in rats via subplantar injections of 1% λ-Carrageenan (CAR) in the right hind leg, and TAP extract was administered via oral gavage 30 min before and 1 h after the CAR injection at doses of 5 mg/kg and 10 mg/kg, respectively. The inflammatory response is usually quantified by the increase in the size of the paw (edema), which is maximal about 5 h after the injection of CAR. CAR-induced inflammation generates the release of pro-inflammatory mediators and reactive oxygen species (ROS). Furthermore, the inflammatory state induces the pain that involves the peripheral nociceptors, but above all it acts centrally at the level of the spinal cord. Our results showed that the TAP extracts reduced paw histological changes, neutrophil infiltration, mast cell degranulation, and oxidative stress. Additionally, the oral administration of TAP extracts decreased thermal and mechanical hyperalgesia, along with a reduction in spinal microglia and the markers of nociception. In conclusion, we demonstrate that TAP extract is able to modulate inflammatory, oxidative, and painful processes, and is also useful in the treatment of the symptoms associated with paw edema.

Effects of R-flurbiprofen and the oxygenated metabolites of endocannabinoids in inflammatory pain mice models.

Pain is one of the cardinal signs accompanying inflammation. The prostaglandins (PGs), synthetized from arachidonic acid by cyclooxygenase (COX)-2, are major bioactive lipids implicated in inflammation and pain. However, COX-2 is also able to metabolize other lipids, including the endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA), to give glycerol ester (PG-G) and ethanolamide (PG-EA) derivatives of the PGs. Consequently, COX-2 can be considered as a hub not only controlling PG synthesis, but also PG-G and PG-EA synthesis. As they were more recently characterized, these endocannabinoid metabolites are less studied in nociception compared to PGs. Interestingly R-profens, previously considered as inactive enantiomers of nonsteroidal anti-inflammatory drugs (NSAIDs), are substrate-selective COX inhibitors. Indeed, R-flurbiprofen can selectively block PG-G and PG-EA production, without affecting PG synthesis from COX-2. Therefore, we compared the effect of R-flurbiprofen and S-flurbiprofen in models of inflammatory pain triggered by local administration of lipopolysaccharides (LPS) and carrageenan in mice. Remarkably, the effects of flurbiprofen enantiomers on mechanical hyperalgesia seem to depend on (i) the inflammatory stimuli, (ii) the route of administration, and (iii) the timing of administration. We also assessed the effect of administration of the PG-Gs, PG-EAs, and PGs on LPS-induced mechanical hyperalgesia. Our data support the interest of studying the nonhydrolytic endocannabinoid metabolism in the context of inflammatory pain.

κ-Carrageenan Oligosaccharides Inhibit the Inflammation of Lipopolysaccharide-Activated Microglia Via TLR4/NF-κB and p38/JNK MAPKs Pathways.

Microglial inflammation plays an essential role in neurodegenerative disease. Our previous studies had shown that κ-carrageenan oligosaccharides (KOS) could inhibit the excessive activation of microglia that induced by LPS, while the interrelated mechanisms were still indistinct. Therefore, we detected the inflammatory signaling pathway on LPS-activated microglia that pretreat by different content of KOS to reveal the mechanism on KOS's inhibition of microglia inflammatory response. ELISA was used to detect the effects of KOS on the secretion of interleukin-1 (IL-1ß), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and prostaglandin E2 (PG-2) by LPS-activated microglia, respectively. The production of reactive oxygen species (ROS) and nitric oxide (NO) in microglia cells was detected by flow cytometry, and the protein expression of immunoinflammation-related signaling pathways were detected by Western Blot. The results showed that KOS could significantly protected the microglia from the over-activated inflammatory by inhibiting the release of inflammatory cytokines and the oxidative stress response. And KOS could reduce the expression of the protein that related to the TLR4/NF-κB and p38/JNK MAPKs pathways activated by LPS in microglia. However, there may be no specific target of KOS in cells. Therefore, KOS, a natural algal source oligosaccharide, has immunomodulatory effects and can be used as a potential intervention therapy for inflammatory related neurodegenerative diseases.

Leonurine inhibits the TXNIP/NLRP3 and NF-κB pathways via Nrf2 activation to alleviate carrageenan-induced pleurisy in mice.

Oxidative stress and inflammation play important roles in pleurisy. Leonurine (Leo) has been confirmed to exert antioxidative and antiinflammatory effects in many preclinical experiments, but these effects have not been studied in pleurisy. The aim of this study was to explore the therapeutic effect and mechanism of Leo in a carrageenan (CAR)-induced pleurisy model. In this study, we found that the increase of reactive oxygen species (ROS), myeloperoxidase (MPO), and malondialdehyde (MDA) and decrease of glutathione (GSH) induced by CAR could be reversed by the treatment of Leo. Leo effectively reduced the levels of proinflammatory cytokines interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), and the percentages of mature macrophages and increased the levels of antiinflammatory cytokines (IL-10). Furthermore, Western blotting revealed that Leo significantly activated the Nrf2 pathway to restrain the thioredoxin-interacting protein/NOD-like receptor protein 3 (TXNIP/NLRP3) and nuclear factor kappa-B (NF-κB) pathways. However, the protective effect of Leo was significantly weakened in Nrf2-deficient mice. These results indicate that Leo confers potent protection against CAR-induced pleurisy by inhibiting the TXNIP/NLRP3 and NF-κB pathways dependent on Nrf2, which may serve as a promising agent for attenuating pleurisy.

Beneficial interaction of pycnogenol with indomethacin in rats.

Cyclooxygenase 2 (COX-2) is responsible for the therapeutic effects of indomethacin, while inhibition of the COX-1 enzyme and oxidative stress are responsible for its gastro-toxic effects. It has been reported that pycnogenol increases the expression of COX-1, suppresses the expression rate of COX-2 and oxidative stress. Our aim in this study is to investigate the antiinflammatory activities of indomethacin, pycnogenol, and their combination (PI) in rats and to examine their effects on stomach tissue. In the study, anti-inflammatory activity was investigated in carrageenan-induced inflammatory paw edema in albino Wistar male rats. Effects on stomach tissue were performed by applying the previous method. PI, indomethacin and pycnogenol were the best suppressors of carrageenan inflammation and oxidative stress in paw tissue, respectively. While the groups with the lowest COX-1 activity in paw tissue were IC, PIC and PC, respectively, PIC, IC and PC were the ones that best inhibited the increase in COX-2 activity. Pycnogenol inhibited the increase of malondialdehyde, the decrease of total glutathione and COX-1 in the stomach, and significantly suppressed the formation of indomethacin ulcers. Our experimental results showed that pycnogenol reduced the toxic effect of indomethacin on the stomach and increased anti-inflammatory activity. This beneficial interaction of pycnogenol and indomethacin suggests that PI will provide superior success in the treatment of inflammatory diseases.

Phytochemical evaluation of Cucumis prophetarum: protective effects against carrageenan-induced prostatitis in rats.

Phytochemical study of the MeOH extract of Cucumis prophetarum fruits (family Cucurbitaceae) by using different chromatographic techniques led to the isolation of three metabolites; spinasterol (1), cucurbitacin B (2), and 2-O-ß-D-glucopyranosylcucurbitacin E (3). Their chemical structures were created on the basis of physical, chemical, spectroscopic data 1D (1H and 13C NMR), and 2D NMR (HSQC and HMBC), as well as similarity with literature data. Cucurbitacin B (Cu-B) (2) was found to be the major constituent. Potential protective activities of MeOH extract, CHCl3, and EtOAc fractions and Cu-B were evaluated against carrageenan-induced prostatic inflammation in rats. Acute toxicity was assessed by evaluating LD50. Pretreatment with CHCl3 fraction and Cu-B ameliorated the rise in the prostate index and obviously protected against histopathological changes. Further, MeOH, extract, CHCl3, and EtOAc fractions as well as Cu-B significantly protected against oxidative stress in prostatic tissues. The anti-inflammatory activities of the extract, fractions and Cu-B were confirmed by ameliorating the rise in prostatic content of the inflammatory mediators TNF-α, IL-1ß, COX-2, and iNOS induced by carrageenan. In addition, the rise in the chemotactic factors were myeloperoxidase (MPO), F4-80, and monocyte chemoattractant protein-1 (MCP-1) was significantly hampered. In conclusion, three known compounds (1-3) were isolated from Cucumis prophetarum fruits. Cu-B (2) was the major identified compound. Particularly, CHCl3 fraction and isolated Cu-B exhibited potent anti-inflammatory activity against carrageenan-induced prostatitis. The anti-inflammatory activity can be attributed, at least partly, to inhibition of neutrophil and macrophage infiltration into prostatic tissues.

Evaluation of Sida cordifolia L. for its potential against thrombosis in experimental models.

Thrombosis, the formation of blood clots due to platelet aggregation, vascular injury or hypercoagulability, leads to cardiovascular pathologies including myocardial or cerebral infarction. Antiplatelet and thrombolytic agents have promising effects in ameliorating thromboembolism and dissolving blood clots. However, the associated limitations generate the need to explore agents from natural origin. The aim of the study was to explore the potential of aqueous methanolic extract (Sc.Cr) of an indigenous plant, Sida cordifolia L., traditionally used for cardiovascular complaints. Sc.Cr was evaluated by clot lysis assay, acute pulmonary embolism, carrageenan-induced tail vein thrombosis and ferric chloride-induced carotid arterial thrombosis models. Hemostasis parameters were increased in a dose-dependent manner. Histological studies showed restoration with clear alveolar spaces and less red blood cell congestion. Significant reduction in infarcted length of thrombus, escalation in coagulation parameters with a profound decrease in platelet count (PC) were observed. Arterial occlusion time was increased with a reduction in weight of thrombus dose-dependently with significant augmentation in PT and APTT. Sc.Cr was also analyzed for phytochemical constituents and antioxidant potential. The results demonstrated the antithrombotic and thrombolytic potential of Sc.Cr using in vitro and in vivo experimental models.

Chaetomium globosum extract mediated gold nanoparticle synthesis and potent anti-inflammatory activity.

Gold nanoparticles (AuNPs) are gaining a lot of attention in recent decades from researchers due to their unique optoelectronic properties and their significance in the field of biomedicine. Keeping this in view, our research work was designed to investigate gold nanoparticles obtained by using a fungal endophytic strain Chaetomium globosum, isolated from Vitex negundo which showed significant activity on enzyme inhibition. In the present study, the fungal isolate C. globosum was characterized using HPLC and LC-MS. A novel compound Catechin was matched with standard Catechin. Further, the endophyte C. globosum extract was utilized to synthesize gold nanoparticles (CgAuNPs) which was analysed by UV-visible spectroscopy. The CgAuNPs exhibited wine red color and the absorption peak appeared at 542 nm confirming the formation of the AuNPs. Further, Fourier Transmission Infrared Spectroscopy (FTIR) was performed to confirm the various functional groups present in mycosynthesized CgAuNPs. FTIR analysis demonstrated the presence of amines, flavonoids, as well as the presence of amide I linkage which possibly reduces Au+ to Au0. The synthesized CgAuNPs exhibited potential cytotoxicity against HeLa cells in a dose dependent manner. Further, CgAuNPs demonstrated significant anti-inflammatory activity. Overall, the present work provides insights into the design of nano delivery and may be applied for clinical studies in future.

Acute Peripheral Inflammation Increases Plasma Concentration of Hypoglycemic Agent Nateglinide with Decreased Hepatic Drug-Metabolizing Activity in Rats.

The effects of inflammation on hypoglycemic agents were evaluated in male rats with acute peripheral inflammation (API). Nateglinide (NTG) was utilized as a model compound, since it is a hepatically-metabolized compound and its metabolism is mainly mediated by CYP 2C11 enzyme. In the experiments, rats were subjected to carrageenan injection into their hind paws for API induction, and the plasma concentration profiles of NTG were then examined. In addition, pooled liver microsomes were prepared from control and API rats, and the hepatic drug-metabolizing activity toward NTG and the hepatic expression of CYP2C11 protein were evaluated. It was shown that the plasma concentration of NTG following its intravenous administration decreases at a slower rate in API rats than that in control rats. It was also indicated in the incubation study with the liver microsomes that the hepatic drug-metabolizing activity toward NTG decreases in API rats. Additionally, it was revealed in Western immunoblotting that the hepatic expression of CYP2C11 protein decreases in API rats. These findings suggest that inflammation occurring in peripheral tissues brings about a decrease in hepatic NTG metabolism by suppressing the hepatic expression of CYP2C11 protein, causing an alteration of the plasma concentration profile of NTG with its impaired elimination.

Protective effect of the intravenous anesthetic propofol against a local inflammation in the mouse carrageenan-induced air pouch model.

Aim: 2,6-Di-isopropylphenol (propofol) is an intravenous general anesthetic widely used in the operating room for general anesthesia and in the intensive care unit for sedation. The mouse air pouch model is versatile in studying the anti-inflammatory effect of a drug on a local inflammation, which is induced by a variety of substances. In this study, using the carrageenan-induced air pouch inflammation model, we tested whether propofol mitigates inflammation occurring locally in the mouse air pouch. Methods: Carrageenan-induced air pouch inflammation model. Results: Propofol inhibited the production of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in the pouch. Propofol also inhibited the production of neutrophil chemokines, KC and MIP-2, and decreased the number of both Ly-6G+/CD11b+ cells (assumed to be primarily neutrophils) and Ly-6G-/CD11b+ cells (assumed to be monocytes/macrophages), recruited into the pouch at 3 h after injection of carrageenan. Conclusion: Propofol has an anti-inflammatory property in the carrageenan-induced mouse air pouch local inflammation model, by inhibiting the production of pro-inflammatory cytokines (TNF-α and IL-6), as well as by inhibiting the production of chemokines (KC and MIP-2), which might be associated with the inhibition of intra-pouch recruitment of white blood cells.

Reduction of paw edema and liver oxidative stress in carrageenan-induced acute inflammation by Lobaria pulmonaria and Parmelia caperata, lichen species, in mice.

Paw edema volume reduction is a useful marker in determining the anti-inflammatory effect of drugs and plant extracts in carrageenan-induced acute inflammation. In this study, the anti-inflammatory effect of Lobaria pulmonaria (LP) and Parmelia caperata (PC), two lichen species, was examined in carrageenan-induced mouse paw edema test. Compared to the controls in carrageenan-induced inflammation (n = 5/group), our results showed that pretreatment by single oral doses with PC extract (50-500 mg/kg) gives better results than LP extract (50-500 mg/kg) in terms of anti-edematous activity, as after 4 h of carrageenan subplantar injection, paw edema formation was inhibited at 82-99% by PC while at 35-49% by LP. The higher anti-inflammatory effect of PC, at all doses, was also observed on the time-course of carrageenan-induced paw edema, displaying profile closely similar to that obtained with diclofenac (25 mg/kg), an anti-inflammatory drug reference (all p < 0.001). Both LP and PC, at all doses, significantly ameliorated liver catalase (CAT) activity (all p < 0.05). However, superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity and glutathione (GSH) levels were found increased in liver of PC- compared to LP-carrageenan-injected mice. Our findings demonstrated on one hand higher preventive effects of PC compared to LP in a mouse carrageenan-induced inflammatory model and suggested, on the other hand, that anti-inflammatory effects elicited by the two lichens were closely associated with the amelioration in the endogenous antioxidant status of liver.

Spinal PAR2 Activation Contributes to Hypersensitivity Induced by Peripheral Inflammation in Rats.

The mechanisms of inflammatory pain need to be identified in order to find new superior treatments. Protease-activated receptors 2 (PAR2) and transient receptor potential vanilloid 1 (TRPV1) are highly co-expressed in dorsal root ganglion neurons and implicated in pain development. Here, we examined the role of spinal PAR2 in hyperalgesia and the modulation of synaptic transmission in carrageenan-induced peripheral inflammation, using intrathecal (i.t.) treatment in the behavioral experiments and recordings of spontaneous, miniature and dorsal root stimulation-evoked excitatory postsynaptic currents (sEPSCs, mEPSCs and eEPSCs) in spinal cord slices. Intrathecal PAR2-activating peptide (AP) administration aggravated the carrageenan-induced thermal hyperalgesia, and this was prevented by a TRPV1 antagonist (SB 366791) and staurosporine i.t. pretreatment. Additionally, the frequency of the mEPSC and sEPSC and the amplitude of the eEPSC recorded from the superficial dorsal horn neurons were enhanced after acute PAR2 AP application, while prevented with SB 366791 or staurosporine pretreatment. PAR2 antagonist application reduced the thermal hyperalgesia and decreased the frequency of mEPSC and sEPSC and the amplitude of eEPSC. Our findings highlight the contribution of spinal PAR2 activation to carrageenan-induced hyperalgesia and the importance of dorsal horn PAR2 and TRPV1 receptor interactions in the modulation of nociceptive synaptic transmission.

Experimental Evaluation of Food-Grade Semi-Refined Carrageenan Toxicity.

The safety of food additives E407 and E407a has raised concerns in the scientific community. Thus, this study aims to assess the local and systemic toxic effects of the common food additive E407a in rats orally exposed to it for two weeks. Complex evaluations of the effects of semi-refined carrageenan (E407a) on rats upon oral exposure were performed. Local effects of E407a on the intestine were analyzed using routine histological stains and CD68 immunostaining. Furthermore, circulating levels of inflammatory markers were assessed. A fluorescent probe O1O (2- (2'-OH-phenyl)-5-phenyl-1,3-oxazole) was used for evaluating the state of leukocyte cell membranes. Cell death modes of leukocytes were analyzed by flow cytometry using Annexin V and 7-aminoactinomycin D staining. Oral administration of the common food additive E407a was found to be associated with altered small and large intestinal morphology, infiltration of the lamina propria in the small intestine with macrophages (CD68+ cells), high systemic levels of inflammation markers, and changes in the lipid order of the phospholipid bilayer in the cell membranes of leukocytes, alongside the activation of their apoptosis. Our findings suggest that oral exposure to E407a through rats results in the development of intestinal inflammation.

Antioxidant Serine-(NSAID) Hybrids with Anti-Inflammatory and Hypolipidemic Potency.

A series of L-serine amides of antioxidant acids, such as Trolox, (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid (phenolic derivative of cinnamic acid) and 3,5-di-tert-butyl-4-hydroxybenzoic acid (structurally similar to butylated hydroxytoluene), was synthesized. The hydroxy group of serine was esterified with two classical NSAIDs, ibuprofen and ketoprofen. The Trolox derivatives with ibuprofen (7) and ketoprofen (10) were the most potent inhibitors of lipid peroxidation (IC50 3.4 µΜ and 2.8 µΜ), several times more potent than the reference Trolox (IC50 25 µΜ). Most of the compounds decreased carrageenan-induced rat paw edema (37-67% at 150 µmol/kg). They were moderate inhibitors of soybean lipoxygenase, with the exception of ibuprofen derivative 8 (IC50 13 µΜ). The most active anti-inflammatory compounds exhibited a significant decrease in lipidemic indices in the plasma of Triton-induced hyperlipidemic rats, e.g., the most active compound 9 decreased triglycerides, total cholesterol and low-density lipoprotein cholesterol by 52%, 61% and 70%, respectively, at 150 µmol/kg (i.p.), similar to that of simvastatin, a well-known hypocholesterolemic drug. Since the designed compounds seem to exhibit multiple pharmacological actions, they may be of use for the development of agents against inflammatory and degenerative conditions.