Proteoglycan synthesis rate as a novel method to measure blood‐induced cartilage degeneration in non‐haemophilic and haemophilic rats

Abstract

Introduction:Haemophilic animal models are used to study blood-induced cartilage damage, but quantitative and sensitive outcome measures are needed. Aim:To develop a novel quantitative method for detecting early cartilage degeneration in a haemophilic rat model of blood-induced joint damage. Methods: The 35 Sulphate incorporation ( 35 SO 4 2− assay) was applied to tibial and patellar cartilage of wild-type rats to quantify baseline proteoglycan synthesis and to evaluate the effect of 4-day blood exposure in vitro. Next, haemarthrosis was induced in 39 FVIII-deficient rats and characterized by changes in knee joint diameter and development of bone pathology (using micro-CT). Four-and 16-day posthaemarthrosis proteoglycan synthesis rate (PSR) was assessed using the 35 SO 4 2− assay, with the contralateral knee as control.Results: In vitro, a decrease in PSR in tibial and patellar cartilage was demonstrated following blood exposure. In vivo, joint diameter and development of bone pathology confirmed successful induction of haemarthrosis. In the blood-exposed knee, tibial and patellar PSR was inhibited 4 and 16 days after induced haemarthrosis.Interestingly, at day 16 the proteoglycan synthesis in the contralateral knee was also inhibited to an extent correlating with that of the blood-exposed knee. Conclusion: For the first time, early changes in cartilage matrix synthesis upon blood exposure were quantified with the 35 SO 4 2− assay in a haemophilic rat model, establishing this assay as a novel method to study blood-induced cartilage damage. K E Y W O R D S arthropathies, cartilage, experimental animal models, haemarthrosis, haemophilia | e89 PULLES Et aL.

Effects of Joint Immobilization and Treadmill Exercise on Articular Cartilage After ACL Reconstruction in Rats

“…Previous studies revealed that blood exposure of rat knee articular cartilage or cultured human articular cartilage decreased proteoglycan synthesis. 17 , 40 Therefore, in the posterior region in the ACLR + IM group, a dramatic decrease in chondrocyte density and blood clot formation would result in proteoglycan loss and cartilage thinning.…”

On‐demand treatment with the iron chelator deferasirox is ineffective in preventing blood‐induced joint damage in haemophilic mice

“…In addition, both knee joints of joint bleed naive haemophilic mice (10 animals; 20 joints) were included as external controls, since the use of an internal control for this model is under debate due to the observation of contralateral joint damage upon blood exposure. 17 All animals were between three and 4 months of age. This study was performed according to the European Convention on Animal Care and was approved by the institutional and national animal ethical committee (project number AVD115002016451).…”

“…The hind legs were removed, knee joints isolated and prepared for histological staining. 22 So far, the focus of histological evaluation has been mainly on the tibiofemoral compartment, while blood‐induced patellar cartilage 17 and bone damage 18 , 23 , 24 , 25 , 26 are noticed in rodent models as well. This is supported by the finding that blood spreads throughout the joint cavity and ascends to the patella upon hemarthrosis in haemophilic mice.…”

“…Taking into account an expected 25% loss, 16 a total of 66 animals (30 males and 36 females) were included in the study. In addition, both knee joints of joint bleed naive haemophilic mice (10 animals; 20 joints) were included as external controls, since the use of an internal control for this model is under debate due to the observation of contralateral joint damage upon blood exposure 17 . All animals were between three and 4 months of age.…”