Intra-articular mucilages: behavioural and histological evaluations for a new model of articular pain

Abstract

Objectives The creation of a new valid preclinical model of articular pain by the intra‐articular (i.a.) injection of mucilages for the screening of new treatments against arthritis. Methods A single intra‐articular injection (20 μl) of mucilages (from Althaea officinalis roots and Linum usitatissimun seeds) or vegetal components (Amorphophallus konjac gum powder and β‐glucan, used as reference standard) were assessed in the rat. The pathology progression was monitored by behavioural measurements (paw pressure test, von Frey test, incapacitance test and beam balance test) and compared to that induced by the i.a. injections of monoiodioacetate (MIA) and Complete Freund's Adjuvant (CFA), well‐recognized models of osteoarthritis and rheumatoid arthritis, respectively. Key findings Among all, the mucilage of L. usitatissimun showed the best pro‐algic profile inducing a painful long‐lasting condition. Hypersensitivity was characterized as a mixed form of inflammatory and neuropathic pain by the responsiveness to ibuprofen (100 mg/kg, p.o.) and pregabalin (30 mg/kg, p.o.). The histological evaluation of joint showed a damage that represents both MIA and CFA features. Conclusions In conclusion, a single i.a. injection of L. usitatissimun mucilage can represent a valid model to assess articular pain in the rat for the screening of new treatments against arthritis.

Intra-Articular Route for the System of Molecules 14G1862 from Centella asiatica: Pain Relieving and Protective Effects in a Rat Model of Osteoarthritis

“…Briefly, rats were lightly anesthetized by 2% isoflurane, the left leg skin was sterilized with 75% ethyl alcohol, and the lateral malleolus located by palpation; then, a 28-gauge needle was inserted vertically to penetrate the skin and turned distally for insertion into the articular cavity at the gap between the tibiofibular and tarsal bone until a distinct loss of resistance was felt. A volume of 20 μL of solution was then injected (day 1) [ 23 ]. Control rats received 20 μL of saline solution.…”

“…A balance beam test [30] consisted of the rats being placed on a narrowstrip of wood (30 cm × 1.3 cm) while balancing and the scoring standards were as follows: 0 point, the four limbs were all on the wood in a balance situations; 1 point, limbs of one side were able to grasp the wood or shake on the wood; 2 points, one or two limbs slipped from the wood; 3 points, three limbs slipped from the wood; 4 points, suspended on the wood and fell over after struggle [23].…”

Deepening the Mechanisms of Visceral Pain Persistence: An Evaluation of the Gut-Spinal Cord Relationship

“…Morphine hydrochloride (S.A.L.A.R.S., Como, Italy) was administered subcutaneously and intrathecally [15,16]; ibuprofen [17] and otilonium bromide [18] (Carbosynth, Compton, UK) were administered orally. Pregabalin [17,19] and amitryptiline hydrochloride [20] (Sigma-Aldrich, Milan, Italy) were administered intraperitoneally and intrathecally. Dexamethasone [21] (Carbosynth, Compton, UK) was administered intraperitoneally.…”

The Pharmacology of Pain Associated With the Monoiodoacetate Model of Osteoarthritis

“…Chemically induced OA models, on the other hand, require much less intervention, consisting, normally, of a single intra-articular injection of substances, such as monoiodoacetate (MIA), papain, or mucilage, that can target different components of the joint (Lampropoulou-Adamidou et al, 2014; Micheli et al, 2019). Because of their artificial onset, these models do not recapitulate the natural onset of the human disease but have, nevertheless, found pre-clinical value, namely because they originate robust and reproducible pain phenotypes, making them particularly adequate to test the efficacy of new pharmacological agents to treat OA pain (Bove et al, 2003; Micheli et al, 2019). In addition, chemically induced models are easy to implement and require less invasive procedures than surgically induced models.…”