Intra-articular injection of collagenase in the knee of rats as an alternative model to study nociception associated with osteoarthritis

Abstract

IntroductionAnimal models currently used in osteoarthritis-associated pain research inadequately reproduce the initiating events and structural pathology of human osteoarthritis. Conversely, intra-articular injection of collagenase is a structurally relevant model, as it induces articular degeneration both by digesting collagen from cartilage and by causing articular instability, thereby reproducing some of the main events associated with osteoarthritis onset and development. Here, we evaluated if the intra-articular injection of collagenase can be an alternative model to study nociception associated with osteoarthritis.MethodsOsteoarthritis was induced by two intra-articular injections of either 250 U or 500 U of collagenase into the left knee joint of adult male Wistar rats. A six weeks time-course assessment of movement- and loading-induced nociception was performed by the Knee-Bend and CatWalk tests. The effect of morphine, lidocaine and diclofenac on nociceptive behaviour was evaluated in animals injected with 500 U of collagenase. Joint histopathology was scored for both doses throughout time. The expression of transient receptor potential vanilloid 1 (TRPV1) in ipsilateral dorsal root ganglia (DRG) was evaluated.ResultsAn increase in nociceptive behaviour associated with movement and loading of affected joints was observed after intra-articular collagenase injection. With the 500 U dose of collagenase, there was a significant correlation between the behavioural and the histopathological osteoarthritis-like structural changes developed after six weeks. One week after injection of 500 U collagenase, swelling of the injected knee and inflammation of the synovial membrane were also observed, indicating the occurrence of an early inflammatory reaction. Behavioural changes induced by the 500 U dose of collagenase were overall effectively reversed by morphine and lidocaine. Diclofenac was effective one week after injection. TRPV1 expression increased six weeks after 500 U collagenase injection. ConclusionWe conclude that the intra-articular injection of 500 U collagenase in the knee of rats can be an alternative model for the study of nociception associated with osteoarthritis, since it induces significant nociceptive alterations associated with relevant osteoarthritis-like joint structural changes.

Injury of primary afferent neurons may contribute to osteoarthritis induced pain: an experimental study using the collagenase model in rats

“…Vehicle administration had no effect in both tests (data not shown, previously published in Ref. 7,31). Gabapentin had no sedative effect as determined by the normal exploratory behaviour in the CatWalk test.…”

“…injections were performed using a Hamilton syringe with a 26G needle inserted through the patellar ligament into the left knee joint cavity. Animals received two injections, one on day 0 and another on day 3, of 25 mL of either sterile saline (control group) or 500 U of type II collagenase from Clostridium histolyticum (SigmaeAldrich) dissolved in saline and filtered through a 0.22 mm membrane 7,8 . Animals were randomly assigned to each group before the first injection.…”

“…7. DRG sections were incubated with either mouse anti-a2d-1 (1:100, Sigma Aldrich), mouse anti-ATF-3 (1:200, Abcam), rabbit anti-NPY (1:2000, SigmaeAldrich) or rabbit anti-SP (1:1000, Peninsula Labs), overnight at room temperature.…”

“…A full analysis of the histological changes induced by this model was performed previously in Ref. 7. Here, we focused on the most relevant parameters for this model: total cartilage degeneration width (TCDW), measured as the percentage of the total width of the medial tibial plateau (MTP); significant cartilage degeneration width (SCDW), also as a percentage of the MTP; zonal depth ratio (ZDR) of lesions in zone 2, in the centre of the MTP, the most severely affected region 7 ; cartilage degeneration score (CDS) in zone 2 7 ; osteophytes score (OS); synovial membrane inflammation score (SMIS).…”

“…We have recently shown that the injection of collagenase leads, after 6 weeks of disease progression, to a set of both histopathological and nociceptive changes that are consistent with the development of OA-like alterations 7 . Collagenase induces the degeneration of articular cartilage (AC) both by directly digesting collagen from the extracellular matrix of cartilage 8 , and as a consequence of articular instability due to increased joint laxity 9 , thereby reproducing some of the main features associated with OA onset and development in humans 10e15 , and being a clinically relevant experimental approach to the study of OA-associated pain.…”