Search Results (20)

Background: Thymus numidicus Poiret. (Lamiaceae) is an endemic plant with well-known antibacterial properties. It has been largely used in traditional Algerian medicine. This study aimed to compare the chemical composition of essential oils (EOs) extracted from leaves and flowers using the gas chromatography–mass spectrometry method, as well as to investigate its analgesic and anti-inflammatory activities. Results: The EOs were rich in monoterpenes and classified as a thymol chemotype. In vivo experiments revealed that acute treatment with T. numidicus EO (20 and 80 mg/kg) significantly increased the thermal threshold on the hot-plate at all tested hours compared to the control animals (p < 0.001, respectively), while only the higher dose had a similar effect to the metamizole group at 2 and 3 h. In the mechanical stimulus test, both doses of the EO led to a late analgesic effect presented with increased paw withdrawal threshold only during the third hour compared to the control group (p < 0.05, respectively). In the plethysmometer test both doses of the EO dose-dependently reduced paw volume with nearly 10% and 15% compared to the control animals at all tested hours (p < 0.001, respectively), with a more pronounced volume reduction in the higher dose. In a neuropathic pain model, the EO (20 mg/kg and 80 mg/kg) dose-dependently increased the withdrawal latency time towards thermal stimuli and enhanced the paw withdrawal threshold in response to mechanical pressure at all tested hours compared to the CCI-group (p < 0.001, respectively). These findings demonstrate the potent analgesic and anti-inflammatory effects of T. numidicus EO in models of acute and neuropathic pain. Full article

The adaptation of the body when exposed to a lower-than-usual temperature is a challenge that involves neuro-endocrine–immune mechanisms and affects the pharmacokinetics and/or pharmacodynamics of drugs taken before or after cold exposure. The experiments presented in this study clearly show differences in the analgesic effect of an exogenously introduced model substance (C-terminal fragment of calcium-binding protein, spermatid-specific 1) before and after cold exposure compared to its effect at an ambient temperature. The model substance used for the experiments is an octapeptide, TDIFELLK, which was synthesized via standard solid-phase peptide synthesis. Preliminary studies proved TDIFELLK’s analgesic activity. The ANOVA analysis performed showed statistically significant differences in the pain thresholds, measured by a paw pressure test, in 109 rats distributed among 14 groups and subjected to cold exposure according to different set-ups. Cold exposure immediately after TDIFELLK administration appears to enhance its analgesic effect, while cold exposure before administration reduces the effect. In some of the set-ups, antagonists of the most significant for analgesia receptors, i.e., opioid, cannabinoid, and serotonergic, were also introduced. The results showed that cold exposure had a modulating influence on the effect of the exogenously administered substances. The modulating effect was manifested differently depending on whether the intake occurred before or after cold exposure. The results also showed that the interaction with individual mediator systems was also subjected to differences depending on intake occurring before and after cold exposure. Full article

Reliable, standardized balance tests for dogs are not available yet. The purpose of this study was to investigate the reliability of static and dynamic posturography in healthy dogs. Healthy dogs (n = 20) were positioned with four paws longitudinally and with the forepaws only transversely on a modified pressure-sensitive balance platform (Posturomed-FDM-JS, Zebris, Isny, Germany). Three static and dynamic posturographic trials were recorded (recording duration: 20 s) and repeated after 7–14 days. Center of pressure (COP) parameters COP-path-length (PL; mm), 95% COP-confidence-ellipse-area (CEA; mm²), and COP-average-velocity (AV; mm/s) were calculated for the first steady-state 5 s intervals of each trial. The reliability of COP parameters was assessed with robust linear mixed effects models with nested random effects of patient and trial. The training effect was analyzed using Cohen’s d. For static posturography, PL, CEA, and AV did not differ significantly between time points; CEA had the highest reliability (p = 0.92). For dynamic posturography, AV and PL differed significantly between time points (AV: p ≤ 0.043; PL: p ≤ 0.045). Slight training effects were observed for transverse positioning (Cohen’s d: PL 0.65; AV 0.267) and moderate training effects for longitudinal positioning (Cohen’s d: PL: 0.772; AV: 0.783). This study showed that static posturography on a modified Posturomed-balance platform was reliable in healthy dogs but indicated training effects during dynamic posturography. Full article

The present research study aims to appraise the potential of polyphenol-rich extracts from two Brassica rapa varieties on antioxidant, anti-inflammatory and analgesic activities using carrageenan-induced paw edema model in rats. Methanol extracts of peels and pulps of Brassica rapa yellow root (BRYR) and Brassica rapa white root (BRWR) were prepared using the soxhlet extraction technique. All four extracts were analyzed by reversed-phase high-pressure liquid chromatography (RP-HPLC) for the polyphenols, and results showed that 10 phenolic acids and 4 flavonoids were detected. Gallic acid was the major phenolic acid (174.6–642.3 mg/100 g of dry plant material) while catechin was the major (34.45–358.5 mg/100 g of dry plant material) flavonoid detected in the extracts. The total phenolic contents (TPC) of BRYR peel, BRWR peel, BRYR pulp and BRWR pulp extracts were in the range of 1.21–5.01 mg/g of dry plant material, measured as GAE, whereas the total flavonoid contents (TFC) were found in the range of 0.90–3.95 mg/g of dry plant material, measured as QE. BRYR peel extract exhibited the best DPPH radical scavenging activity (IC₅₀, 3.85 µg/mL) and reducing potential as compared with other extracts. The in vivo anti-inflammatory potential was assessed by carrageenan-induced rat paw edema, and the analgesic potential was investigated by a hot plate test. Suppression of biochemical inflammatory biomarkers including C-reactive protein (CRP), rheumatoid factor (RF) and tumor necrosis factor (TNF-α), and interleukin-6 (IL-6) concentration were also determined. Results showed that BRYR peel extracts reduced paw edema and suppressed the production of TNF-α, IL-6, CRP and RF most significantly, followed by BRWR peel, BRYR pulp and BRWR pulp extracts. In addition, histopathology observation also supports the anti-inflammatory effect of peel extracts as being greater than that of root pulp extracts. Moreover, it was observed that the analgesic effect of the root-peel extracts was also more pronounced as compared with root-pulp extracts. It can be concluded that BRYR peel extract has higher phenolic contents and showed higher suppression of TNF-α, IL-6, CRP and RF, with strong antioxidant, anti-inflammatory and analgesic effects. Full article

Background: Bioconjugates are promising alternatives for the multiple targeting of any disease. Pyrrole heterocycle is well known with many activities and is a building block of a lot of medical drugs. On the other hand, peptides are short molecules with many advantages such as small size, ability to penetrate the cell membrane and bond-specific receptors, vectorizing potential, etc. Thus, hybrid molecules between peptide and pyrrole moiety could be a promising alternative as an anti-pain tool. Methods: New bioconjugates with a general formula Pyrrole (α-/β-acid)-FELL-OH (NH₂) were synthesized using Fmoc/OtBu peptide synthesis on solid support. HPLC was used to monitor the purity of newly synthesized bioconjugates. Their structures were proven by electrospray ionization mass spectrometry. The Paw Pressure test (Randall–Selitto test) was used to examinate the analgesic activity. Hydrolytic stability of targeted structures was monitored in three model systems with pH 2.0, 7.4 and 9.0, including specific enzymes by means of the HPLC-UV method. Results: The obtained results reveal that all newly synthesized bioconjugates have analgesic activity according to the used test but free pyrrole acids have the best analgesic activity. Conclusions: Although free pyrrole acids showed the best analgesic activity, they are the most unstable for hydrolysis. Combination with peptide structure leads to the hydrolytic stabilization of the bioconjugates, albeit with slightly reduced activity. Full article

Valorphin (V1) is a naturally occurring peptide derived from hemoglobin that has been found to have an affinity for opioid receptors and exhibits antinociceptive and anticonvulsant activity. Some of its synthetic analogs containing an aminophosphonate moiety show structure-dependent potent antinociceptive effects. This study aimed to reveal a detailed picture of the antinociceptive mechanisms and behavioral effects of V1 and its recently synthesized phosphopeptide analog V2p in rodents using a range of methods. The studied peptides significantly reduced acute (mean V1–9.0, V2p–5.8 vs. controls–54.1 s) and inflammatory (mean V1–57.9 and V2p–53.3 vs. controls–107.6 s) nociceptive pain in the formalin test, as well as carrageenan-induced hyperalgesia (mean V1–184.7 and V2p–107.3 vs. controls–61.8 g) in the paw pressure test. These effects are mediated by activation of opioid receptors with a predominance of kappa in V1 antinociception and by delta, kappa, and mu receptors in V2p-induced antinociception. Both peptides did not change the levels of TNF-alpha and IL-1-beta in blood serum. V1 induces depression-like behavior, and V2p shows a tendency toward anxiolysis and short-term impairment of motor coordination without affecting exploratory behavior. The results characterize valorphin and its derivative as promising analgesics that exert their effects both centrally and peripherally, without causing severe behavioral changes in experimental animals. These encouraging data are a foundation for future studies focusing on the effects of hemorphins after long-term treatment. Full article

Poor tendon–bone interface (TBI) integration is one of the major causes contributing to unsatisfactory healing quality in patients after anterior cruciate ligament (ACL) reconstruction. Type H vessels have been recently found to closely modulate bone formation via regulation of the osteo-angiogenic crosstalk, so the strategies favoring type H vessel formation may be promising therapeutic approaches for improved graft osteointegration. In this study, we reported for the first time the treatment outcome of slit guidance ligand 3 (slit3), a novel proangiogenic factor favoring type H vessel formation, in TBI healing in mice with ACL reconstruction. The mice (n = 87) were divided into three groups for various treatments: hydrogel microparticles (HMP, control group), slit3@HMP, and slit3 neutralizing antibody@HMP (slit3-AB@HMP). Histological analysis, gait performance, radiographic measurement, and biomechanical testing were performed to assess the TBI healing quality. Increased bony ingrowth and reduced fibrous scar tissue was formed at the TBI in the slit3@HMP group when compared to the HMP group. Meanwhile, the slit3-AB@HMP inhibited the osseous ingrowth and increased fibrous scar tissue formation relative to the HMP group. Compared to the HMP group, the slit3@HMP favored type H vessel formation at the TBI while the slit3-AB@HMP impeded it. According to micro-CT assessment, compared to the HMP group, the slit3@HMP significantly increased the peri-tunnel bone mass while the slit3-AB@HMP significantly reduced the peri-tunnel bone mass. The mice in the slit3@HMP group showed the best gait performance in terms of stance time, stride length, paw print area, and stance pressure. Dynamic laxity measurement and tensile testing showed the slit3@HMP group exhibited significantly reduced laxity displacement and improved failure load and stiffness relative to the other two groups. Collectively, the injection of slit3 could be used to enhance tendon–bone integration, which may be ascribed to modulation of angiogenesis–osteogenesis crosstalk coupled by type H vessels. Full article

Background: The inflammatory process represents a specific response of the organism’s immune system. More often, it is related to the rising pain in the affected area. Independently of its origin, pain represents a complex and multidimensional acute or chronic subjective unpleasant perception. Currently, medical doctors prescribe various analgesics for pain treatment, but unfortunately, many of them have adverse effects or are not strong enough to suppress the pain. Thus, the search for new pain-relieving medical drugs continues. Methods: New tetrapeptide analogs of FELL with a generaanalgesic-Glu-X³-X⁴-Z, where X = Nle, Ile, or Val and Z = NH₂ or COOH, containing different hydrophobic amino acids at positions 3 and 4, were synthesized by means of standard solid-phase peptide synthesis using the Fmoc/OtBu strategy in order to study the influence of structure and hydrophobicity on the analgesic activity. The purity of all compounds was monitored by HPLC, and their structures were proven by ESI-MS. Logp values (partition coefficient in octanol/water) for FELL analogs were calculated. Analgesic activity was examined by the Paw-pressure test (Randall-Selitto test). Results: The obtained results reveal that Leu is the best choice as a hydrophobic amino acid in the FELL structure. Conclusions: The best analgesic activity is found in the parent compound FELL and its C-terminal amide analog. Full article

In this work, we report on the in vitro and in vivo pharmacological properties of LP1 analogs to complete the series of structural modifications aimed to generate compounds with improved analgesia. To do that, the phenyl ring in the N-substituent of our lead compound LP1 was replaced by an electron-rich or electron-deficient ring and linked through a propanamide or butyramide spacer at the basic nitrogen of the (−)-cis-N-normetazocine skeleton. In radioligand binding assays, compounds 3 and 7 were found to display nanomolar binding affinity for the μ opioid receptor (MOR) (K_i = 5.96 ± 0.08 nM and 1.49 ± 0.24 nM, respectively). In the mouse vas deferens (MVD) assay, compound 3 showed an antagonist effect against DAMGO ([D-Ala², N-MePhe⁴, Gly-ol]-enkephalin), a highly selective MOR prototype agonist, whereas compound 7 produced naloxone reversible effect at MOR. Moreover, compound 7, as potent as LP1 and DAMGO at MOR, was able to reduce thermal and inflammatory pain assessed by the mouse tail-flick test and rat paw pressure thresholds (PPTs) measured by a Randall–Selitto test. Full article

Tendinopathies represent about 45% of musculoskeletal lesions and they are a big burden in clinics characterized by activity-related pain, focal tendon tenderness and intra-tendinous imaging changes. Many approaches have been proposed for tendinopathies’ management (e.g., nonsteroidal anti-inflammatory drugs, corticosteroids, eccentric exercises, laser therapy), unfortunately with very little support of efficacy or serious side effects, thus making the identification of new treatments fundamental. The aim of the study was to test the protective and pain reliever effect of thymoquinone (TQ)-loaded formulations in a rat model of tendinopathy induced by carrageenan intra-tendon injection (20 µL of carrageenan 0.8% on day 1). Conventional (LP-TQ) and hyaluronic acid (HA)-coated TQ liposomes (HA-LP-TQ) were characterized and subjected to in vitro release and stability studies at 4 °C. Then, TQ and liposomes were peri-tendon injected (20 µL) on days 1, 3, 5, 7 and 10 to evaluate their antinociceptive profile using mechanical noxious and non-noxious stimuli (paw pressure and von Frey tests), spontaneous pain (incapacitance test) and motor alterations (Rota rod test). Liposomes containing 2 mg/mL of TQ and covered with HA (HA-LP-TQ2) reduced the development of spontaneous nociception and hypersensitivity for a long-lasting effect more than the other formulations. The anti-hypersensitivity effect matched with the histopathological evaluation. In conclusion, the use of TQ encapsulated in HA-LP liposomes is suggested as a new treatment for tendinopathies. Full article

Transient receptor potential channels C4/C5 are widely expressed in the pain pathway. Here, we studied the putative analgesic efficacy of the highly selective and potent TRPC4/C5 antagonist HC-070 in rats. Inhibitory potency on human TRPC4 was assessed by using the whole-cell manual patch-clamp technique. Visceral pain sensitivity was assessed by the colonic distension test after intra-colonic trinitrobenzene sulfonic acid injection and partial restraint stress. Mechanical pain sensitivity was assessed by the paw pressure test in the chronic constriction injury (CCI) neuropathic pain model. We confirm that HC-070 is a low nanomolar antagonist. Following single oral doses (3–30 mg/kg in male or female rats), colonic hypersensitivity was significantly and dose-dependently attenuated, even fully reversed to baseline. HC-070 also had a significant anti-hypersensitivity effect in the established phase of the CCI model. HC-070 did not have an effect on the mechanical withdrawal threshold of the non-injured paw, whereas the reference compound morphine significantly increased it. Analgesic effects are observed at unbound brain concentrations near the 50% inhibitory concentration (IC₅₀) recorded in vitro. This suggests that analgesic effects reported here are brought about by TRPC4/C5 blocking in vivo. The results strengthen the idea that TRPC4/C5 antagonism is a novel, safe non-opioid treatment for chronic pain. Full article

The effects on stress-induced analgesia (SIA) from endogenous cannabinoid system (ECS) and nitric oxide (NO) interaction after 1 h of restraint stress were evaluated in male Wistar rats. The animals were subjected to 1 h of restraint and then injected with different combinations of cannabinoid receptor type 1 agonist anandamide (AEA) or antagonist AM251 along with an NO donor, NO precursor, or inhibitor of NO synthase. Nociception was evaluated using paw pressure (PP) or hot plate (HP) tests. AEA was administered immediately after the end of restraint-SIA (r-SIA). Administration of NO precursor reversed the pronociceptive effect of the CB1 agonist on r-SIA. Both the CB1 antagonist and the NOS inhibitor neutralized the pro-analgesic effect of L-arginine (L-arg). Administration of an NO donor, instead, increased r-SIA. Our experiments confirmed that the endogenous cannabinoid and the NO-ergic systems interact in the modulation of r-SIA. This interaction probably implies NO as a second messenger of the ECS. Full article

The methods used in preclinical studies should minimize the suffering and the number of animals but still provide precise and consistent results enabling the introduction of drug candidates into the phase of clinical trials. Thus, we aimed to develop a method allowing us to perform preliminary safety and toxicity studies of candidates for human medicines, while reducing the number of animals. We have devised a method based on a combination of two devices: Plugsys (Transonics System Inc., Ithaca, NY, USA) and PhysioSuite (Kent Scientific Corporation, Torrington, CT, USA), which allow simultaneous registration of nine circulatory and respiratory parameters, and body temperature. Vehicle and adrenaline, or nitroglycerin, as reference substances were administered into the right femoral vein of Wistar rats. Physiological conditions were registered over 60 min after drug administration by measuring systolic, diastolic and mean blood pressure, heart rate (HR), blood perfusion of paw vessels, blood oxygen saturation, respiratory rate, average and peak exhaled CO₂, and body temperature. Blood pressure was measured by cannula placed in the left common carotid artery and connected to the pressure transducer (Plugsys). The other parameters were measured by the PhysioSuite. Adrenaline-induced immediate dose-related hypertension and nitroglycerin hypotension were correlated with the change in blood perfusion. They both increased HR. Adrenaline decreased blood oxygen saturation and slightly affected respiratory parameters, while nitroglycerin caused a progressive increase in respiratory rate and a decrease in the peak of exhaled CO₂. Our method may become an inseparable part of the preliminary safety and toxicity studies of tested drugs, while being an important step towards improving animal welfare. Full article

Osteoarthritis is the most widespread joint-affecting disease. The management of persistent pain remains inadequate and demands new therapeutic strategies. In this study, we explored the pain relieving and protective properties of a single intra-articular (i.a.) injection of khellin loaded in nanovesicles (K-Ves) based on ascorbyl decanoate plus phosphatidylcholine in a rat model of osteoarthritis (OA) induced by monosodium iodoacetate (MIA) treatment. The developed nanovesicles (approximately 136 nm) had a narrow size distribution (PdI 0.26), a good recovery (about 80%) and a worthy encapsulation efficiency (about 70%) with a ζ-potential of about −40 mV. The stability of K-Ves was assessed in simulated synovial fluid. Seven days after the articular damage with MIA, both K-Ves and a suspension of khellin (K, 50 μL) were i.a. injected. K-Ves significantly counteracted MIA-induced hypersensitivity to mechanical noxious (paw pressure test) and non-noxious stimuli (von Frey test) and significantly reduced the postural unbalance related to spontaneous pain (incapacitance test) and the motor alterations (beam balance test) 7 and 14 days after the i.a. injection. K was partially active only on day 7 after the treatment. The histology emphasized the improvement of several morphological factors in MIA plus K-Ves-treated animals. In conclusion, K-Ves could be successfully used for the local treatment of osteoarthritis. Full article

Solidago virgaurea L. is a perennial plant used in European traditional medicine as a diuretic or a remedy for inflammatory conditions of the urinary tract but also for gout, especially in the Balkans. The present study was focused on a preclinical, in vivo evaluation of antihyperuricemic, anti-inflammatory, and antihypertensive effects of a dry extract from S. virgaurea L. (ESV). Colorimetric and HPLC–MS techniques were used to identify the main chemical constituents of ESV. Antihyperuricemic effect of ESV was assessed in a rat model of hyperuricemia induced by the administration of potassium oxonate. Antihypertensive effect of ESV was evaluated in hyperuricemic rats by monitoring systolic blood pressure with a non-invasive blood-pressure recording system. The anti-inflammatory effect of ESV was tested using a rat model of paw edema. The main chemical constituents of ESV were rutin and phenolic acids represented by chlorogenic and caffeic acid. ESV demonstrated significant antihyperuricemic effects in rats due to an uricosuric mechanism. Additionally, ESV reduced the progression of arterial hypertension in hyperuricemic rats and also showed anti-inflammatory properties slightly inferior to diclofenac. The results suggest that ESV could be a natural remedy for the treatment of gout and protection against endothelial dysfunction caused by hyperuricemia. Full article