Upregulation of mRNA of interleukin-1 and -6 in subchondral cystic lesions of four horses.
Authors: von Rechenberg B, Leutenegger C, Zlinsky K, McIlwraith C W, Akens M K, Auer J A
Journal: Equine veterinary journal
Summary
# Editorial Summary Subchondral cystic lesions (SCLs) represent a challenging and often progressive pathology in equine joints, yet the cellular mechanisms driving their expansion remain incompletely understood. Von Rechenberg and colleagues investigated whether pro-inflammatory cytokines interleukin-1beta (IL-1β) and interleukin-6 (IL-6) play a role in SCL progression by examining fibrous tissue and bone from affected lesions in four horses using in situ hybridisation and quantitative real-time PCR. Both cytokines showed significant mRNA upregulation, though with distinct spatial distribution: IL-1β expression concentrated at the lesion periphery adjacent to healthy bone, whilst IL-6 predominated within the central fibrous tissue. The findings suggest these pro-inflammatory mediators, working alongside elevated prostaglandin E2 production, actively drive pathological bone resorption and perpetuate the slow healing, maintenance or enlargement characteristic of SCLs. For practitioners managing these lesions therapeutically, this mechanistic insight supports the rationale for anti-inflammatory interventions targeting cytokine pathways, whether through systemic approaches or intra-articular delivery, and highlights why early intervention before extensive central fibrous tissue colonisation may be critical for preventing progressive cyst expansion.
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Practical Takeaways
- •Subchondral cystic lesions involve active inflammatory cytokine signalling that may perpetuate the lesion and explain their chronic, slow-healing nature
- •Understanding the cytokine profile in SCL could inform future therapeutic targets aimed at modulating IL-1 and IL-6 to promote healing
- •The location-specific upregulation of different cytokines suggests distinct pathological mechanisms operating at the cyst periphery versus centre
Key Findings
- •IL-1beta mRNA was upregulated at the periphery of subchondral cystic lesions adjacent to normal bone
- •IL-6 mRNA was upregulated within fibrous tissue in the centre of subchondral cystic lesions
- •Both IL-1beta and IL-6 are associated with pathological bone resorption in subchondral cystic lesions
- •Upregulated cytokines combined with increased prostaglandin E2 production may explain slow healing and cyst expansion