Elsevier

Osteoarthritis and Cartilage

Volume 15, Issue 9, September 2007, Pages 1053-1060
Osteoarthritis and Cartilage

Interleukin-1 and tumor necrosis factor alpha inhibit repair of the porcine meniscus in vitro1

https://doi.org/10.1016/j.joca.2007.03.003Get rights and content
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Summary

Objective

Injury or removal of the knee meniscus leads to progressive joint degeneration, and current surgical therapies for meniscal tears seek to maximally preserve meniscal structure and function. However, the factors that influence intrinsic repair of the meniscus are not well understood. The goal of this study was to investigate the capacity of meniscus tissue to repair a simulated defect in vitro and to examine the effect of pro-inflammatory cytokines on this process.

Methods

Cylindrical explants were harvested from the outer one-third of medial porcine menisci. To simulate a full-thickness defect, a central core was removed and reinserted immediately into the defect. Explants were cultured for 2, 4, or 6 weeks in serum-containing media in the presence or absence of interleukin-1 (IL-1) or tumor necrosis factor alpha (TNF-α), and meniscal repair was investigated using mechanical testing and fluorescence confocal microscopy.

Results

Meniscal lesions in untreated samples showed a significant capacity for intrinsic repair in vitro, with increasing cell accumulation and repair strength over time in culture. In the presence of IL-1 or TNF-α, no repair was observed despite the presence of abundant viable cells.

Conclusions

This study demonstrates that the meniscus exhibits an intrinsic repair response in vitro. However, the presence of pro-inflammatory cytokines completely inhibited repair. These findings suggest that increased levels of pro-inflammatory cytokines post-injury or under arthritic conditions may inhibit meniscal repair. Therefore, inhibition of these cytokines may provide a means of accelerating repair of damaged or injured menisci in vivo.

Key words

Meniscus
Injury
Cartilage
Integrative repair
IL-1
TNF-α
Osteoarthritis
Knee
Fibrochondrocyte

Cited by (0)

1

Source of support: This study was supported by the Rehabilitation Research and Development Service of the Department of Veterans Affairs, NIH grants AR48182, AR50245, and AG15768. Dr Alfred Hennerbichler was the recipient of an Erwin-Schroedinger-Fellowship of the Austrian Science Fund (project no. J2294) at Duke University Medical Center.