Tetrandrine inhibits the occurrence and development of frozen shoulder by inhibiting inflammation, angiogenesis, and fibrosis

BACKGROUND

Frozen shoulders (FS) is a major clinical concern, where chronic synovial inflammation, abnormal angiogenesis, and fibrosis represent the critical pathologies in the glenohumeral capsule. However, no pharmacotherapy has been introduced to treat this pathology. Tetrandrine (TET) has been proposed as a treatment for many diseases due to its strong anti-inflammatory, anti-angiogenic, and anti-fibrotic effects.

PURPOSE

To study the anti-inflammatory, anti-angiogenic, and anti-fibrotic effects of TET on FS, and identify whether TET can prevent the development of FS in rats.

STUDY DESIGN

A controlled laboratory study.

METHODS

Forty-eight male Sprague-Dawley (SD) rats were randomly divided into control, TET, and FS groups. The TET group was intraperitoneally injected with TET every 2 days. TET and saline treatment were started on the day of FS surgery. After 8 weeks, the animals were sacrificed, and samples were collected for X-ray examination, glenohumeral range of motion (ROM) evaluation, histology and immunohistochemistry analysis, transmission electron microscopy (TEM) observation, and profibrogenic factors as well as proinflammatory cytokines measurements.

RESULTS

No significant difference in shoulder ROM was observed between the TET and control groups, but a significant difference was noted between these groups and the FS group (P < 0.01). Immunohistochemical staining showed no abnormal angiogenesis or fibrosis in the TET group or the control group. However, significant angiogenesis, collagen remodeling, and fibrosis were observed in the FS group, and the expression and proportion of type I and type III collagen in the FS group were significantly higher than those in the TET group or the control group (P < 0.01). TEM observation showed that TET protected the ultrastructure of collagen fibrous reticular arrangement of the articular capsule and prevented the formation of scar-like fibrotic structures, which are unique to FS. The significantly increased expression of Smad7 and the suppressed expression of Smad 2 in the TET group compared with that of the FS group indicated that TET also significantly inhibited the TGF-β1 intracellular signal pathway. The expression of profibrogenic factors and proinflammatory cytokines in the TET group and the control group was significantly lower than that in the TET group (P < 0.01).

CONCLUSION

The results demonstrated that TET protected the normal reticular structure of the capsule during the freezing period and prevented the development of FS by inhibiting inflammation, angiogenesis, and fibrosis in a rat FS model.

CLINICAL RELEVANCE

TET may be a safe and effective clinical medication for preventing and treating FS.

Population Pharmacokinetics of Periarticular Ketorolac in Adult Patients Undergoing Total Hip or Total Knee Replacement Surgery

BACKGROUND

Ketorolac tromethamine has been used for joint infiltration by the orthopedic surgeons as a part of postoperative multimodal analgesia. The objective of this study is to investigate the pharmacokinetic properties of S (-) and R (+) enantiomers of ketorolac in adult patients undergoing total hip (THA) and knee arthroplasty (TKA).

METHODS

Adult patients with normal preoperative renal function received a periarticular infiltration of 30 mg of ketorolac tromethamine along with 100 mL of 0.2% ropivacaine and 1 mg of epinephrine at the end of their THA or TKA surgery. Blood samples were taken from a venous cannula at various time points after infiltration. Pharmacokinetic modeling was performed using PMetrics 1.5.0.

RESULTS

From 18 participants, 104 samples were analyzed. The peak plasma concentration for S (-) ketorolac was found to be lower than that of R (+) ketorolac, for both THA (0.19-1.22 mg/L vs 0.39-1.63 mg/L, respectively) and TKA (0.28-0.60 mg/L vs 0.48-0.88 mg/L, respectively). The clearance of the S (-) ketorolac enantiomer was higher than R (+) ketorolac (4.50 ± 2.27 vs 1.40 ± 0.694 L/h, respectively).

CONCLUSIONS

Our study demonstrates that with periarticular infiltration, S (-) ketorolac was observed to have increased clearance rate and highly variable volume of distribution and lower peak plasma concentration compared to R (+) ketorolac.

Effects of losartan and atorvastatin on the development of early posttraumatic joint stiffness in a rat model

BACKGROUND

After a trauma, exuberant tissue healing with fibrosis of the joint capsule can lead to posttraumatic joint stiffness (PTJS). Losartan and atorvastatin have both shown their antifibrotic effects in different organ systems.

OBJECTIVE

The purpose of this study was the evaluation of the influence of losartan and atorvastatin on the early development of joint contracture. In addition to joint angles, the change in myofibroblast numbers and the distribution of bone sialoprotein (BSP) were assessed.

STUDY DESIGN AND METHODS

In this randomized and blinded experimental study with 24 rats, losartan and atorvastatin were compared to a placebo. After an initial joint injury, rat knees were immobilized with a Kirschner wire. Rats received either losartan, atorvastatin or a placebo orally daily. After 14 days, joint angle measurements and histological assessments were performed.

RESULTS

Losartan increased the length of the inferior joint capsule. Joint angle and other capsule length measurements did not reveal significant differences between both drugs and the placebo. At cellular level both losartan and atorvastatin reduced the total number of myofibroblasts (losartan: 191±77, atorvastatin: 98±58, placebo: 319±113 per counting field, p<0.01) and the percentage area of myofibroblasts (losartan: 2.8±1.8% [p<0.05], atorvastatin: 2.5±1.7% [p<0.01], vs control [6.4±4%], respectively). BSP was detectable in equivalent amounts in the joint capsules of all groups with only a trend toward a reduction of the BSP-stained area by atorvastatin.

CONCLUSION

Both atorvastatin and losartan reduced the number of myofibroblasts in the posterior knee joint capsule of rat knees 2 weeks after trauma and losartan increased the length of the inferior joint capsule. However, these changes at the cellular level did not translate an increase in range of motion of the rats´ knee joints during early contracture development.

Inhibition of Contractile Function in Human Joint Capsule Myofibroblasts by Targeting the TGF-β1 and PDGF Pathways

Background

Contractile myofibroblasts (MFs) accumulate in the joint capsules of patients suffering from posttraumatic joint stiffness. MF activation is controlled by a complex local network of growth factors and cytokines, ending in the increased production of extracellular matrix components followed by soft tissue contracture. Despite the tremendous growth of knowledge in this field, inconsistencies remain in practice and prevention.

Methods and Findings

In this in vitro study, we isolated and cultured alpha-smooth muscle actin (α-SMA) positive human joint capsule MFs from biopsy specimens and investigated the effect of profibrotic and antifibrotic agents on MF function. Both TGF-β1 and PDGF significantly induced proliferation and increased extracellular matrix contraction in an established 3D collagen gel contraction model. Furthermore, both growth factors induced α-SMA and collagen type I gene expression in MFs. TGF-β1 down-regulated TGF-β1 and TGF-β receptor (R) 1 and receptor (R) 2 gene expression, while PDGF selectively down-regulated TGF-β receptor 2 gene expression. These effects were blocked by suramin. Interestingly, the anti-oxidant agent superoxide dismutase (SOD) blocked TGF-β1 induced proliferation and collagen gel contraction without modulating the gene expression of α-SMA, collagen type I, TGF-β1, TGF-β R1 and TGF-β R2.

Conclusions

Our results provide evidence that targeting the TGF-β1 and PDGF pathways in human joint capsule MFs affects their contractile function. TGF-β1 may modulate MF function in the joint capsule not only via the receptor signalling pathway but also by regulating the production of profibrotic reactive oxygen species (ROS). In particular, anti-oxidant agents could offer promising options in developing strategies for the prevention and treatment of posttraumatic joint stiffness in humans.

Preventing effects of joint contracture by high molecular weight hyaluronan injections in a rat immobilized knee model

PURPOSE

To elucidate preventive effects of high molecular weight hyaluronan (HMWHA) on the joint capsule of immobilized knees in rats.

MATERIALS AND METHODS

Unilateral knee joints of rats were immobilized with an internal fixator. Either 50 μl of HMWHA (Im-HA group) or 50 μl of saline (control group) was administered intra-articularly once a week after surgery. Sagittal sections were prepared from the medial midcondylar region of the knee joints and assessed by histological, histomorphometric, and immunohistochemical methods. Gene expressions related to inflammation, fibrotic conditions, and hypoxia were evaluated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Tissue elasticity of the capsule from both groups was examined using a scanning acoustic microscope (SAM).

RESULTS

CD68 positive cells decreased in adhesion areas of the synovial membrane after 1 week in both groups. The length of the superficial layer in the synovial membrane of the Im-HA group was significantly longer than those in the control group over a period of 4 to 8 weeks with significantly small numbers of CD68 positive cells. The gene expressions of IL-6, IL-1β, TGF-β, CTGF, COL1a1, COL3a1, SPARC, and HIF1-α were significantly lower in the Im-HA group compared to those in the control group. The sound speed of the anterior and posterior synovial membrane increased significantly (a reduction in elasticity) in the control group compared to those in the Im-HA group during weeks 1 to 4.

CONCLUSIONS

This study demonstrated that HMWHA injections suppressed inflammatory, fibrotic, and hypoxic conditions observed in the immobilized joint capsule.

Effects of icariin on cytokine-induced ankylosing spondylitis with fibroblastic osteogenesis and its molecular mechanism

The aim of this study is to explore the effects of icariin on cytokine induced ankylosing spondylitis fibroblast osteogenesis type expression and its molecular mechanism. The normal fibroblasts were collected as normal control group, and the fibroblasts of hip joint capsule of AS patients were collected, which were respectively added in fetal bovine serum (group AS), fetal bovine serum and cytokines (BMP-2+TGF-beta 1) (group AS), and cell factor solution (icariin group), and observed of the osteogenic expression of fibroblast, to evaluate the impact of Icariin on it. The ALP activity, the content of collagen, osteocalcin content and cbfa1mRNA and OCmRNA of fibroblast of AS group increased compared to the normal control group and AS control group (P < 0.01), indicating that icariin can significantly inhibit the above changes (P < 0.01). Icariin can inhibit fibroblast further osteogenic differentiation through inhibiting the effect of cytokines on the fibroblast osteogenesis type markers and osteogenic gene expression and osteogenic differentiation.

Mouse limb skeletal growth and synovial joint development are coordinately enhanced by Kartogenin

Limb development requires the coordinated growth of several tissues and structures including long bones, joints and tendons, but the underlying mechanisms are not wholly clear. Recently, we identified a small drug-like molecule - we named Kartogenin (KGN) - that greatly stimulates chondrogenesis in marrow-derived mesenchymal stem cells (MSCs) and enhances cartilage repair in mouse osteoarthritis (OA) models. To determine whether limb developmental processes are regulated by KGN, we tested its activity on committed preskeletal mesenchymal cells from mouse embryo limb buds and whole limb explants. KGN did stimulate cartilage nodule formation and more strikingly, boosted digit cartilaginous anlaga elongation, synovial joint formation and interzone compaction, tendon maturation as monitored by ScxGFP, and interdigit invagination. To identify mechanisms, we carried out gene expression analyses and found that several genes, including those encoding key signaling proteins, were up-regulated by KGN. Amongst highly up-regulated genes were those encoding hedgehog and TGFβ superfamily members, particularly TFGβ1. The former response was verified by increases in Gli1-LacZ activity and Gli1 mRNA expression. Exogenous TGFβ1 stimulated cartilage nodule formation to levels similar to KGN, and KGN and TGFβ1 both greatly enhanced expression of lubricin/Prg4 in articular superficial zone cells. KGN also strongly increased the cellular levels of phospho-Smads that mediate canonical TGFβ and BMP signaling. Thus, limb development is potently and harmoniously stimulated by KGN. The growth effects of KGN appear to result from its ability to boost several key signaling pathways and in particular TGFβ signaling, working in addition to and/or in concert with the filamin A/CBFβ/RUNX1 pathway we identified previously to orchestrate overall limb development. KGN may thus represent a very powerful tool not only for OA therapy, but also limb regeneration and tissue repair strategies.

Molecular determinants of glucocorticoid actions in inflammatory joint diseases

Since their discovery in 1948, glucocorticoids have been widely used clinically to treat inflammatory disorders like rheumatoid arthritis. However, their usefulness, especially in rheumatoid arthritis therapy, is hampered by severe side effects on bone leading to glucocorticoid-induced osteoporosis. The molecular and cellular mechanisms mediating the beneficial and adverse effects remain poorly understood. Nevertheless, advanced molecular biological analyses and in vivo approaches using conditional mutant mice have helped to unravel in part the underlying mechanisms of immunosuppression and side effects of glucocorticoid therapy in arthritis, thereby contributing to an improved understanding of these therapeutically important hormones.

Matrix metalloproteases and tissue inhibitors of metalloproteinases in medial plica and pannus-like tissue contribute to knee osteoarthritis progression

Osteoarthritis (OA) is characterized by degradation of the cartilage matrix, leading to pathologic changes in the joints. However, the pathogenic effects of synovial tissue inflammation on OA knees are not clear. To investigate whether the inflammation caused by the medial plica is involved in the pathogenesis of osteoarthritis, we examined the expression of matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), interleukin (IL)-1β, and tumor necrosis factor (TNF)-α in the medial plica and pannus-like tissue in the knees of patients with medial compartment OA who underwent either arthroscopic medial release (stage II; 15 knee joints from 15 patients) or total knee replacement (stage IV; 18 knee joints from 18 patients). MMP-2, MMP-3, MMP-9, IL-1β, and TNF-α mRNA and protein levels measured, respectively, by quantitative real-time PCR and Quantibody human MMP arrays, were highly expressed in extracts of medial plica and pannus-like tissue from stage IV knee joints. Immunohistochemical staining also demonstrated high expression of MMP-2, MMP-3, and MMP-9 in plica and pannus-like tissue of stage IV OA knees and not in normal cartilage. Some TIMP/MMP ratios decreased significantly in both medial plica and pannus-like tissue as disease progressed from stage II to stage IV. Furthermore, the migration of cells from the pannus-like tissue was enhanced by IL-1β, while plica cell migration was enhanced by TNF-α. The results suggest that medial plica and pannus-like tissue may be involved in the process of cartilage degradation in medial compartment OA of the knee.

Celastrol inhibits lipopolysaccharide-stimulated rheumatoid fibroblast-like synoviocyte invasion through suppression of TLR4/NF-κB-mediated matrix metalloproteinase-9 expression

Invasion of fibroblast-like synoviocytes (FLSs) is critical in the pathogenesis of rheumatoid arthritis (RA). The metalloproteinases (MMPs) and activator of Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) pathway play a critical role in RA-FLS invasion induced by lipopolysaccharide (LPS). The present study aimed to explore the anti-invasive activity of celastrol on LPS-stimulated human RA-FLSs, and to elucidate the mechanism involved. We investigated the effect of celastrol on LPS-induced FLS migration and invasion as well as MMP expression and explored the upstream signal transduction. Results showed that celastrol suppressed LPS-stimulated FLS migration and invasion by inhibiting MMP-9 expression and activity. Furthermore, our results revealed that celastrol inhibited the transcriptional activity of MMP-9 by suppressing the binding activity of NF-κB in the MMP-9 promoter, and suppressed the TLR4/MyD88/NF-κB pathway. Administration of celastrol (0.5 mg/kg and 1 mg/kg, intraperitoneally) daily for 3 weeks in a collagen-induced arthritis rat model markedly alleviated the clinical signs, synovial hyperplasia and inflammatory cell infiltration of joints. In conclusion, celastrol might inhibit FLS migration and invasion induced by LPS by suppressing TLR4/NF-κB-mediated MMP-9 expression, providing a theoretical foundation for the clinical treatment of RA with celastrol.

Profiling the secretion of soluble mediators by end stage osteoarthritis synovial tissue explants reveals a reduced responsiveness to an inflammatory trigger

Objective

Evidence is accumulating that synovial tissue plays an active role in osteoarthritis (OA), however, exact understanding of its contribution is lacking. In order to further elucidate its role in the OA process, we aimed to identify the secretion pattern of soluble mediators by synovial tissue and to assess its ability to initiate cartilage degeneration.

Methods

Synovial tissue explants (STEs) obtained from donors without history of OA (n = 8) or from end stage OA patients (n = 16) were cultured alone or together with bovine cartilage explants in the absence or presence of IL-1α. The secretion of 48 soluble mediators was measured and the effect on glycosaminoglycan (GAG) release and matrix metalloproteinase (MMP) activity was determined.

Results

Normal and OA STEs secreted comparable levels of almost all measured soluble mediators. However, in the presence of IL-1α these mediators were less secreted by OA than by normal STEs of which 15 differed significantly (p<0.01). No effect of normal or OA STEs on GAG release from the cartilage explants was observed, and no differences in MMP activity between OA and normal STEs were detected.

Conclusions

Unexpectedly, a comparable secretion profile of soluble mediators was found for OA and normal STEs while the reduced responsiveness of OA STEs to an inflammatory trigger indicates a different state of this tissue in OA patients. The effects could be the result of prolonged exposure to an inflammatory environment in OA development. Further understanding of the pro-inflammatory and inflammation resolving mechanisms during disease progression in synovial tissue may provide valuable targets for therapy in the future.

Pycnogenol attenuates the inflammatory and nitrosative stress on joint inflammation induced by urate crystals

Acute gouty arthritis results from monosodium urate (MSU) crystal deposition in joint tissues. Deposited MSU crystals induce an acute inflammatory response which leads to damage of joint tissue. Pycnogenol (PYC), an extract from the bark of Pinus maritime, has documented antiinflammatory and antioxidant properties. The present study aimed to investigate whether PYC had protective effects on MSU-induced inflammatory and nitrosative stress in joint tissues both in vitro and in vivo. MSU crystals upregulated cyclooxygenase 2 (COX-2), interleukin 8 (IL-8) and inducible nitric oxide synthase (iNOS) gene expression in human articular chondrocytes, but only COX-2 and IL-8 in synovial fibroblasts. PYC inhibited the up-regulation of COX-2, and IL-8 in both articular chondrocytes and synovial fibroblasts. PYC attenuated MSU crystal induced iNOS gene expression and NO production in chondrocytes. Activation of NF-κB and SAPK/JNK, ERK1/2 and p38 MAP kinases by MSU crystals in articular chondrocytes and synovial fibroblasts in vitro was attenuated by treatment with PYC. The acute inflammatory cell infiltration and increased expression of COX-2 and iNOS in synovial tissue and articular cartilage following intra-articular injection of MSU crystals in a rat model was inhibited by coadministration of PYC. Collectively, this study demonstrates that PYC may be of value in treatment of MSU crystal-induced arthritis through its anti-inflammatory and anti-nitrosative activities.

Shoulder adhesive capsulitis: manipulation and arthroscopic arthrolysis or intra-articular steroid injections?

PURPOSE

The aim of this study was to compare shoulder manipulation and arthroscopic arthrolysis with glenohumeral steroid injections in patients affected by idiopathic adhesive shoulder capsulitis.

METHODS

In this prospective study we randomly assigned patients to enter group A (23 patients, shoulder manipulation and arthroscopic arthrolysis) and group B (21 patients, glenohumeral steroid injections). Patients were followed-up at three, six and 12 weeks, and at six and 12 months with the Constant and Murley, ASES, UCLA and SST evaluation scales. Moreover, passive forward flexion, abduction, and internal and external rotations were recorded.

RESULTS

Range of motion showed satisfactory results in both groups at final follow-up: in group A the mean ABD increased from 60° to 154°, ER from 20° to 40°, and FF from 75° to 174°; in group B, ABD raised from 76° to 145°, ER from 20° to 35°, and FF from 115° to 164°. All the evaluation scales performed increased significantly at final follow-up in both groups. However, while patients of group A had already reached significant improvement at the six-week follow-up (p <0.03), in group B this happened only at the 12 week follow-up (p <0.03).

CONCLUSIONS

Both types of treatment were effective in improving final range of motion; however, while patients of group A accomplished their goal by the six-week follow-up, in group B the same result was obtained at the 12-week follow-up.

The snake venom metalloproteinase BaP1 induces joint hypernociception through TNF-alpha and PGE2-dependent mechanisms

BACKGROUND AND PURPOSE

Matrix metalloproteinases (MMPs) have been implicated in joint tissue destruction in arthritis. However, MMPs have not been assigned a role in joint pain. We investigated the ability of BaP1, a metalloproteinase from Bothrops asper snake venom, with structural homology to MMPs, to induce joint hypernociception.

EXPERIMENTAL APPROACH

Animals received intra-articular (i.art.) BaP1. Hypernociception was assessed using the rat-knee joint articular incapacitation test. Cell influx, prostaglandin E(2) (PGE(2)), and TNF-alpha levels were assessed in joint exudates following BaP1 injection.

KEY RESULTS

BaP1 (5 microg per joint) provoked hypernociception between 1 and 6 h after i.art. injection. Cell influx, mostly neutrophils, was maximal 3 h after BaP1 i.art. injection. BaP1 also led to increase in PGE(2) and TNF-alpha levels in the joint exudates. Pretreatment with either indomethacin (4 mg.kg(-1) i.p.) or with an anti-TNF-alpha antiserum (i.art.) significantly inhibited both BaP1-induced joint hypernociception and cell influx. In isolated rat peritoneal macrophages, BaP1 increased cyclooxygenase (COX)-2 expression, while not altering that of COX-1.

CONCLUSIONS AND IMPLICATIONS

This is the first demonstration that a metalloproteinase promotes joint hypernociception. This effect involves local release of PGE(2) and TNF-alpha. BaP1-induced increase in PGE(2) is associated to increased COX-2 expression in macrophages. Blocking PGE(2) or TNF-alpha inhibits BaP1-induced hypernociception. In addition to unravelling a hitherto unknown mechanism whereby TNF blockade provides analgesia in arthritis, the data show, for the first time that MMPs are involved in inflammatory joint hypernociception and induce COX-2 expression.

Effects and mechanisms of catechin for adjuvant arthritis in rats

The present study was carried out to investigate the effects of catechin on adjuvant arthritis (AA) in the rat and its possible mechanisms of action. AA was induced by metatarsal footpad injection with complete Freund's adjuvant in male Sprague-Dawley rats. The secondary inflammatory reaction was evaluated through assessment of hind paw swelling, polyarthritis index, and pain response. Proliferation of synoviocytes and the activity of interleukin-1 were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Tumor necrosis factor-alpha, prostaglandin E(2) (PGE(2)), and cyclic adenosine monophosphate levels in synoviocytes were measured by radioimmunoassay. The PGE(2) receptor, EP(2), was analyzed by Western blot analysis. Intragastric administration of catechin (60 and 120 mg/kg) significantly suppressed secondary inflammatory paw swelling, pain response, and polyarthritis index. It also inhibited production of interleukin-1, tumor necrosis factor-alpha, and PGE(2) and increased cyclic adenosine monophosphate levels in rats with AA. In the immunoblot analysis, catechin could upregulate expression of EP(2) in the synoviocytes of rats with AA. The results showed that catechin reduced secondary inflammation in rats with AA; this outcome reflects its ability to mediate cAMP levels, upregulate expression of EP(2), and inhibit secretion of proinflammatory cytokines in rats with AA.

Effect of curing time and concentration for a chemical treatment that improves surface gliding for extrasynovial tendon grafts in vitro

The purpose of this study was to evaluate whether treatment time and concentration of these reagents have an effect on the resulting gliding resistance. Forty peroneus longus (PL) tendons were used, from 20 adult mongrel dogs, along with the A2 pulley obtained from the ipsilateral hind paw. After the baseline gliding resistance was measured, the PL tendons were treated with one of three concentrations of hyaluronic acid (HA) and 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) or N-hydroxysuccinimide (NHS) mixed with 10% gelatin for various times (5, 30, and 60 min). Tendon friction was measured over 1000 cycles of simulated flexion/extension motion. Gliding resistance of the untreated PL tendons had no significant difference among the groups. After surface treatment with low concentration of HA and EDC/NHS for 5-min cure, the gliding resistance was similar to that of the untreated PL tendon and significantly higher than its 30- and 60-min treatment. For the rest of high concentration of HA and EDC/NHS groups, the gliding resistance was lower than that of untreated PL tendon. However, there was no significant difference among the timing points. It is possible to optimize the effect of surface treatment on friction and durability by regulating cure time and concentration of reagents in a canine extrasynovial tendon in vitro.

Endothelin ETB receptors inhibit articular nociception and priming induced by carrageenan in the rat knee-joint

The participation of the endothelin system on nociception and priming induced by carrageenan in the knee-joint was investigated. Intra-articular (i.a.) carrageenan (300 microg) caused long-lasting nociceptive effects (i.e., increases in paw elevation time [PET]), which were potentiated by endothelin-1 (dual endothelin ETA/ETB receptor agonist) and inhibited by sarafotoxin S6c (endothelin ETB receptor agonist; both at 30 pmol, i.a., 24 h beforehand). Priming the naive joint with carrageenan augmented nociceptive responses to a second carrageenan challenge, 72 h later. Carrageenan-induced priming, but not nociception, was potentiated by local BQ-788 (10 nmol, i.a., 15 min before priming; endothelin ETB receptor antagonist; N-cis-2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D-1-methoxycarbonyl-tryptophanil-D-norleucine), but BQ-123 (endothelin ETA receptor antagonist; cyclo [D-Asp-Pro-D-Val-Leu]) was ineffective. Sarafotoxin S6c markedly suppressed carrageenan-induced priming to nociception triggered by carrageenan, endothelin-1 or sarafotoxin S6c, and BQ-788 prevented this action. Thus, selective endothelin ETB receptor agonists inhibit carrageenan-induced nociception and priming in the naive joint. This priming effect of carrageenan to nociception evoked by subsequent inflammatory insults is limited by an endothelin ETB receptor-operated mechanism.

[The effect of ultra high molecular weight polyethylene particle on the tissues of joint prosthesis]

OBJECTIVE

To study the effect of the high molecular weight polyethylene on the periprosthetic tissue in vivo as to give some reference to treatment of loosening hip arthroplasty.

METHODS

Every lower limb of 20 New Zealand white rabbits was implanted a Co-Cr-Mo plug in femur by intercondylar notch. 15 mg polyethylene particles, dispersed in 1.5 ml normal saline solution, were injected into one knee joint. The other knee joint was injected 1.5 ml normal saline solution as control. This procedure was repeated 2,4,6,8 and 10 weeks after the implantation. Both of two lower limbs were given a X-ray examination 10 weeks to assess if there were periprosthetic osteolysis and loosening of the plugs. All animals were killed 2 weeks afer the last injection. The distribution of polyethylene in the knee joint capsule was examined to understand if there were loosening of implants or tissue change around implants. Knee joint capsule tissues and periprosthetic tissues were examined by optical microscope.

RESULTS

Nine cases formed fibrous membrane and four cases formed new bone around prostheses in experiment group. Eleven cases formed new bone and two cases formed fibrous membrane in control group (P < 0.05) The X-ray results indicated that the plugs were in distal medulla of femur. There was no sign of periprosthetic osteolysis, implants loosening or new bone formation. Optical microscope study indicated that there were a lot of polyethylene particles inside the capsule. The polyethylene particles were surrounded by multinucleated foreign-body giant cells and fibroblast. In some cases, there were fibroblasts and fibrous tissue around plug. There were no polyethylene particles and multinucleated foreign-body giant cells around plug in the marrow. There were a lot of polyethylene particles on the joint surface. The bone surface that contacted multinucleated foreign-body giant cells was coarse.

CONCLUSION

Maximizing ultra high molecular weight polyethylene can restrain rabbit periprosthetic bone formation.

The role of capsular distention in the arthroscopic management of arthrofibrosis of the knee: A technical consideration

Arthroscopic treatment of arthrofibrosis of the knee is a technically challenging procedure. Capsular distention with fluid before arthroscopy results in easier and safer insertion of arthroscopic instruments with improved arthroscopic visualization. In addition, it stretches the entire capsule, including the difficult to access posterior capsule. This report describes a simple technique for capsular distention before arthroscopic treatment of arthrofibrosis of the knee.

Abrogation of alpha-adrenergic vasoactivity in chronically inflamed rat knee joints

It has previously been shown that chronic inflammation causes a reduction in sympathetic nerve-mediated vasoconstriction in rat knees. To determine whether this phenomenon is due to an alteration in smooth muscle adrenoceptor function, the present study compared the alpha-adrenoceptor profile of blood vessels supplying the anteromedial capsule of normal and chronically inflamed rat knee joints. While the rats were under urethan anesthesia, the alpha(1)-adrenoceptor agonists methoxamine and phenylephrine and the alpha(2)-adrenoceptor agonist clonidine (0.1-ml bolus; dose range 10(-12)-10(-7) mol) were applied to exposed normal rat knees, resulting in a dose-dependent fall in capsular perfusion. Comparison of drug potencies indicated that alpha(2)-adrenergic effects > alpha(1)-vasoactivity. One week after intra-articular injection of Freund's complete adjuvant to induce chronic joint inflammation, the vasoconstrictor effects of methoxamine, phenylephrine, and clonidine were all significantly attenuated compared with normal controls. These findings show that the preponderance of sympathetic adrenergic vasoconstriction in the anteromedial capsule of the rat is carried out by postjunctional alpha(2)-adrenoceptors. Chronic joint inflammation compromises alpha(1)- and alpha(2)-adrenoceptor function, and this change in alpha-adrenergic responsiveness may help explain the perfusion changes commonly associated with inflammatory arthritis.

Nitric oxide modulates articular sensory discharge and responsiveness to bradykinin in normal and arthritic rats in vivo

Nitric oxide is implicated in peripheral nociceptive processing. This study determined the effects of the nitric oxide synthase inhibitor, L-NAME, on neural discharge from articular C-fibre afferents innervating normal and arthritic ankle joints in anaesthetized rats. Intra-arterial injection of L-NAME (10-20 mg kg(-1)) increased neural discharge in normal and arthritic ankle joints, whereas D-NAME (30 mg kg(-1)) had no effect. The excitation induced by L-NAME (20 mg kg(-1)) was reduced by co-injecting the nitric oxide precursor, L-arginine (50 mg kg(-1)). L-NAME (20 mg kg(-1)) also enhanced responsiveness to bradykinin (10 microg) but only in arthritic rats, whereas L-arginine (50 mg kg(-1)) reduced the excitation by bradykinin (30 microg) in both groups. These results provide evidence that nitric oxide modulates articular C-fibre activity and reduces responsiveness to bradykinin.

Examination of colocalization of calcitonin gene-related peptide- and substance P-like immunoreactivity in the knee joint of the dog

It is generally assumed that the majority of substance P (SP)-containing afferents are also immunoreactive for calcitonin gene-related peptide (CGRP). In order to determine whether this is also the case in articular afferents where the contents of these peptides are low, we carried out a double labeling study using Fast Blue (FB) as a retrograde tracer injected into the center of the knee joint cavity of the dog together with immunohistochemistry for SP and CGRP. After 7-36 days of survival, dorsal root ganglia (DRGs, L4-S1) were removed. Labeled cells were found mainly (94%) in L5 - 6 DRGs, and SP- and CGRP-like immunoreactivity was found in about 17 and 29% of FB-labeled cells, respectively. The coexistence of SP and CGRP was observed in 10.4% of articular afferents and only 62.7% of SP-positive articular neurons contained CGRP, a much lower ratio than in other afferents of the dog such as testicular afferents. Our data suggest that these peptides are not always released together and that they do not always work together in the joint under normal conditions.

Distention arthrography in the treatment of adhesive capsulitis of the shoulder

PURPOSE

Adhesive capsulitis involving the glenohumeral joint (frozen shoulder) is an insidious and painful condition that results in gradual loss of joint motion. Recovery is frequently prolonged despite multiple therapeutic maneuvers. The authors investigate the mechanism of action and the long-term clinical result of distention arthrography for the treatment of patients with frozen shoulder.

PATIENTS AND METHODS

Sixteen patients with adhesive capsulitis of the shoulder were treated with therapeutic capsular distention by using intra-articular injection of a 30-mL mixture of lidocaine, corticosteroid, and contrast media immediately following diagnostic arthrography.

RESULTS

Capsular disruption was demonstrated in all cases. Thirteen patients (80%) experienced immediate pain relief and increased shoulder mobility. This improvement was maintained over a follow-up interval of 6 months or more. Disruption occurred at the subscapular bursa in eight patients, the subacromial bursa in six, and the distal bicipital tendon sheath in two. These latter two patients had no pain relief.

CONCLUSION

Arthrographic distention of the constricted capsule appears to be an excellent therapeutic intervention for achieving rapid symptomatic relief from adhesive capsulitis.

Does the glenohumeral joint capsule have proprioceptive capability?

We performed a clinical study examining 60 volunteers with stable shoulder joints randomized to two groups. In group 1 we injected 5 ml lidocaine intra-articularly. In group 2 we injected 5 ml saline with 5 ml contrast dye the same way. After the injection we measured the amount of passive anteroposterior translation that occurred during anterior and posterior drawer tests and the amount of inferior subluxation during downward stress. We documented the extent of the passive glenohumeral translation using ultrasound. We had no complications related to the intra-articular injection or to the stability measurement. After the injection neither group had significant pain, and the patients were not apprehensive about the ensuing stability test. In group 1 (lidocaine) anteroposterior translation of 13.2 +/- 6.3 mm was seen in the anterior and posterior drawer test, whereas in group 2 (no lidocaine) the anteroposterior translation was only 6.8 +/- 3.2 mm. The difference between the two groups was statistically significant (P < 0.05). With downward stress during the sulcus test the distance between the acromion and the humeral head increased by 5.6 mm (+/- 3.2) in group 1 and by 2.7 mm (+/- 2.1) in group 2. This difference was also statistically significant (P < 0.05). Clinical consequences: Taking our preliminary findings into account, the capsule of the glenohumeral joint seems to have proprioceptive capability. Nerve fibres and mechanoreceptors seem to be localized in the capsule tissue, being part of a physiological feedback mechanism. If our conclusions proprioceptive capability. Nerve fibres and mechanoreceptors seem to be localized in the capsule tissue, being part of a physiological feedback mechanism.