Comparison of pain behaviour and osteoarthritis progression between anterior cruciate ligament transection and osteochondral injury in rat models

Abstract

Objectives: In this study, we compared the pain behaviour and osteoarthritis (OA) progression between anterior cruciate ligament transection (ACLT) and osteochondral injury in surgically-induced OA rat models.

Methods: OA was induced in the knee joints of male Wistar rats using transection of the ACL or induction of osteochondral injury. Changes in the percentage of high limb weight distribution (%HLWD) on the operated hind limb were used to determine the pain behaviour in these models. The development of OA was assessed and compared using a histological evaluation based on the Osteoarthritis Research Society International (OARSI) cartilage OA histopathology score.

Results: Both models showed an increase in joint pain as indicated by a significant (p < 0.05) decrease in the values of %HLWD at one week post-surgery. In the osteochondral injury model, the %HLWD returned to normal within three weeks, while in the ACLT model, a significant decrease in the %HLWD was persistent over an eight-week period. In addition, OA progression was more advanced in the ACLT model than in the osteochondral injury model. Furthermore, the ACLT model exhibited a higher mean OA score than that of the osteochondral injury model at 12 weeks.

Conclusion: The development of pain patterns in the ACLT and osteochondral injury models is different in that the OA progression was significant in the ACLT model. Although both can be used as models for a post-traumatic injury of the knee, the selection of appropriate models for OA in preclinical studies should be specified and relevant to the clinical scenario.Cite this article: T. Tawonsawatruk, O. Sriwatananukulkit, W. Himakhun, W. Hemstapat. Comparison of pain behaviour and osteoarthritis progression between anterior cruciate ligament transection and osteochondral injury in rat models. Bone Joint Res 2018;7:244-251. DOI: 10.1302/2046-3758.73.BJR-2017-0121.R2.

Keywords: Anterior cruciate ligament transection; Osteoarthritis progression; Osteochondral injury; Pain; Surgically induced osteoarthritis model.

Images showing the induction of surgically induced osteoarthritis models: a) anterior cruciate ligament transection; b) osteochondral defect.

Fig. 2

Graph showing the course of time for the development of an osteoarthritis (OA)-related pain profile in surgically-induced OA models. The pain-related behavioural results were expressed as the mean percentage of weight-bearing distribution on the operated hind limb (*p < 0.05 versus sham and naïve groups). Each point represents the mean and standard error of the mean of each group. ACLT, anterior cruciate ligament transection.

Histopathological evaluation of representative haematoxylin and eosin (H&E) staining sections of articular cartilage from the rat femoral condyle in the (a) naïve and (b) sham groups at 12 weeks post-surgery, and in the (c to e) anterior cruciate ligament transection (ACLT) and (f to h) osteochondral injury groups at four, eight and 12 weeks post-surgery, respectively (original magnification, x 100).

Graphs showing Osteoarthritis Research Society International (OARSI) scores obtained from the anterior cruciate ligament transection (ACLT) (a) and osteochondral defect (b) model groups at different study timepoints, including at four, eight and 12 weeks post-surgery. Values were expressed as the mean and standard error of the mean (** p < 0.01 and **** p < 0.0001).

Fig. 5

Graph showing Osteoarthritis Research Society International (OARSI) scores obtained from the anterior cruciate ligament transection (ACLT) and osteochondral defect model groups at the end of the follow-up period. Values were expressed as the mean and standard error of the mean (**** p < 0.0001).