Objectiveto analyze the effects of hyaluronic acid of different molecular weights in an experimental model of osteoarthritis in rabbits.Methodsforty‐four male California rabbits were divided randomly into three groups and underwent resection of the anterior cruciate ligament in his right knee. After three weeks of the surgical procedure began three weekly intra‐articular injections of hyaluronic acid native (Polireumin®)‐PR, hyaluronic acid branched chain (Synvisc®)‐S and 0.9% saline‐P. All animals were sacrificed after twelve weeks of surgery and tibial plateau infiltrated the knees were dissected. Histological cartilage of the support areas of the tibial plateaus were stained with Alcian Blue pH 1.0, Alcian Blue pH = 2.5 and toluidine blue for research on the amount of proteoglycans. The intensity of staining was quantified on a Zeiss microscope apparatus Imager Z2 MetaSystems and analyzed by software MetaferMsearch.Resultsthe effect of chondroprotetor hyaluronic acids used in the study was confirmed when compared to the control group, but the comparison made between them, there was no statistically significant difference regarding chondroprotetion.Conclusionthe hyaluronic acids tested had chondroprotective effect, with no statistical difference with regard to the different molecular weights.
ObjectiveTo analyze, from the immunohistochemical perspective, the effects of hyaluronic acid of different molecular weights in an experimental model of osteoarthritis in rabbits.MethodsForty-four male California rabbits were randomly assigned to three different groups (PR, S, and P) and submitted to the resection of the anterior cruciate ligament of the right knee. Three weeks after the surgical procedure, three intra-articular weekly injections were carried out with low-molecular-weight native hyaluronic acid (Hyalgan®) to PR group, high molecular weight branched chain hyaluronic acid (Synvisc®) to group S, and saline solution 0.9% to group P. All animals were sacrificed 12 weeks after the surgical procedure, and the tibial plateaus of the infiltrated knees were then dissected. Histological sections of cartilage from the tibial plateau support areas were stained with immunohistochemical markers in order to investigate the amount of metalloproteases (MMPs 3 and 13) and their inhibitors (TIMPs 1 and 3). The staining intensity was quantified on a Zeiss Imager.Z2 Metasystems microscope and analyzed by Metafer4 Msearch software.ResultsThe chondroprotective effect of the hyaluronic acids used in the study was demonstrated when compared to the control group. However, the comparison between them presented no significant statistical difference regarding chondroprotection.ConclusionThe injection of saline solution demonstrated signs of OA development, while adding native hyaluronic acid of low molecular weight (Hyalgan®) and hyaluronic acid of high molecular weight (Synvisc®) protected the articular cartilage in this model of OA.
Objective: To evaluate the effects of intra-articular injections of corticosteroids, native hyaluronic acid and branched-chain hyaluronic acid in experimentally-induced osteoarthrosis. Methods: 44 rabbits underwent anterior cruciate ligament resection and were then divided into four groups of eleven. Group 1: one intra-articular injection of saline solution per week, for three weeks; Group 2: three injections (one per week) of native hyaluronic acid; Group 3: three injections (one per week) of branched-chain hyaluronic acid; Group 4: two injections of betamethasone with an interval of three weeks. The cartilage of the tibial plateaus was evaluated macroscopically twelve weeks after surgery. Changes to the joint surface were graded as follows: Grade 0: smooth joint surface without relief changes; Grade 1: rough surface without any depressions; Grade 2: similar to grade 1, but with depressions on the joint surface; and Grade 3: subchondral bone exposure. The statistical analysis consisted of the use of Student's t test, chi-square test and analysis of variance (ANOVA). The significance level used was 5%. Results: A statistical difference was found between the control group and the three study groups 2, 3, 4 in relation to the development and severity of arthrosis. However, there was no difference between the groups regarding the drugs studied. Conclusion: A similar degree of attenuation of the osteoarthrosis process in the rabbits’ knees was found with the use of intra-articular injections of low-molecular-weight and high-molecular-weight glycosaminoglycans, and the corticosteroid betamethasone, compared with placebo.
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