Efficacy of hyaluronic acid or steroid injections for the treatment of a rat model of rotator cuff injury

Abstract

This study evaluated dorsal root ganglia from C3-C7, analyzed gait, and compared the expression of calcitonin generelated peptide (CGRP) which was a marker of inflammatory pain in a rat rotator cuff tear model in which the supraspinatus and infraspinatus tendons were detached; comparisons were made to a sham group in which only the tendons were exposed. Fluorogold was injected into the glenohumeral joint 21 days after surgery in both groups, and saline, steroids, or hyaluronic acid was injected into the glenohumeral joint in the rotator cuff tear group 26 days after surgery. The proportions of CGRP-immunoreactive neurons were higher and the gait parameters were impaired in the rotator cuff tear group compared to in the sham group. However, the CGRP expression was reduced and the gait was improved with steroid or hyaluronic acid injection compared to saline, suggesting that both hyaluronic acid and steroid injections suppressed of inflammation which thought to be provided pain relief. While there were no significant differences, the suppression of CGRP expression and the improved gait after hyaluronic acid and steroid injections suggested that both methods were effective for rat rotator cuff tear model. Keywords: rotator cuff tear model; pain relief; hyaluronic acid; dorsal root ganglion; CatWalkThe main symptoms of a rotator cuff tear (RCT) are shoulder pain and limited range of motion. Conservative treatment for RCT consists of medication, fomentation, or injections into the subacromial bursa (SAB) or glenohumeral joint (GHJ). In addition, physical rehabilitation has also been used. Although both steroid 1-3 and hyaluronic acid (HA) injections have been commonly used as a conservative treatment for RCT, it remains unknown which method is more effective for pain relief 2,4-6 Moreover, repeated steroid injections may result in local tissue degradation, including tendon tearing and steroid arthropathy. 1 Although the cause of pain in shoulder pathology has not been fully clarified, calcitonin gene-related peptide (CGRP) was found to be highly expressed in both the GHJ and SAB in a rat contracture shoulder model. These results indicate that up-regulation of CGRP might be closely related to the cause of pain in frozen shoulder; 7 the same mechanism of up-regulation of CGRP has also been hypothesized to be related to RCT of inflammatory pain. For both the GHJ and SAB, sensory information is transmitted from free nerve endings through the dorsal root ganglia (DRG) at C3-C7 to the spinal cord and brain. 8 For investigation of inflammation-related pain, evaluation at the level of the DRG is important especially the expression of CGRP.The purpose of the present study was (i) to evaluate DRG neurons innervating the GHJ and SAB using immunohistochemistry for CGRP in a rat RCT model and (ii) to determine whether steroid or HA injection would provide more effective in rotator cuff tear model. MATERIALS AND METHODSAll animal protocols were approved by the Ethics Committee of Chiba University and conducted in accorda...

Intraarticularly-Injected Mesenchymal Stem Cells Stimulate Anti-Inflammatory Molecules and Inhibit Pain Related Protein and Chondrolytic Enzymes in a Monoiodoacetate-Induced Rat Arthritis Model

“…Since central sensitization of pain of shoulder joint origin can be investigated in the spinal dorsal horn of C5 [ 19 , 20 ], we studied CGRP expression at C5. The expression of CGRP at this site in the control group (untreated, Saline−/MIA−/MSC−) was compared with that of the other groups.…”

“…These findings drew our attention to the anti-inflammatory and pain suppressive properties of MSC, leading us to investigate the state of central sensitization after their intraarticular injection. Also, since shoulder joint pain evaluation in a shoulder joint disease model has been reported to be most feasible at C5, we focused on the C5 spinal dorsal horn [ 19 , 20 ]. As investigated items, pain and CGRP, which has been used in the evaluation of central sensitization in spinal dorsal horn inflammation [ 25 , 26 , 27 ], were applied.…”

Intraarticular injection of processed lipoaspirate cells has anti-inflammatory and analgesic effects but does not improve degenerative changes in murine monoiodoacetate-induced osteoarthritis

“…Functionally, DRG neurons can be classified into three different types; i) large neurons, which are involved in proprioception [27], ii) small neurons with axon terminals containing among other neurochemicals, both substance P and CGRP, two pain-related neuropeptides [28–30], and iii) small neurons containing isolectin-B4 (IB4, a structural protein of Griffonia simplicifolia ) in their synapses but lack substance P and CGRP. CGRP is known to cause hyperalgesia, and high levels of CGRP are thought to be involved in inflammation-related pain [31, 32]. Intraarticular injection of MIA was reported to induce significant up-regulation of substance P and CGRP mRNA expression in DRG neurons, as well as a significant increase in substance P and CGRP immunoreactivity in the synovium, periosteum, and subchondral bone, compared to the control [33].…”

<p>Chrysin Attenuates the NLRP3 Inflammasome Cascade to Reduce Synovitis and Pain in KOA Rats</p>

“…As we all know, CGRP is highly related to hyperalgesia, and high levels of CGRP are often considered to be related to inflammation-related pain. 40 In this paper, the reason why we chose the MIA model is that the MIA model is particularly relevant to OA-related pain, accompanied by hyperalgesia and allodynia in the major and minor parts of the rat, which has the advantages of simple induction, noninvasiveness, induce inflammation, easy formation of joint pain, and similar to pathology and pain changes in human osteoarthritis. In addition, the KOA+Chrysin group showed an increase in the cold pain threshold and PWT compared with the Normal group.…”