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Home / Equine Research Bank / Osteoarthritis Cartilage / Synovial incorporation of polyacrylamide hydrogel after inje...
Osteoarthritis and cartilage2016; 24(11); 1999-2002; doi: 10.1016/j.joca.2016.07.007

Synovial incorporation of polyacrylamide hydrogel after injection into normal and osteoarthritic animal joints.

Abstract: Polyacrylamide hydrogel (PAAG) is a non-toxic, non-degradable synthetic product, used for years in the augmentation of soft tissues. Preliminary results in animals and humans have suggested long-lasting beneficial effects on symptoms of osteoarthritis (OA). The aim of this histopathological study was to investigate whether intra-articular injection of PAAG is integrated into synovial tissue in normal and OA animal joints, and if this integration is sustained. (A) A prospective, controlled, longitudinal study of normal knee joints injected with PAAG was performed in 10 rabbits, following the animals up to 1 year, and (B) a post mortem examination was carried out up to 2 years post-injection on 18 horse joints which had previously been treated with 1-2 injections of 2 ml PAAG for clinically and radiologically diagnosed OA. Integration of the injected gel was evident at day 10 in the rabbit and by day 14 in the horse, with proliferation and invasion of synovial cells into the gel. By day 90 in rabbit joints and day 30 in horse joints, the gel had formed a sub-synovial layer, which was traversed by thin strands of connective tissue with vessels and covered by a synovial lining facing the joint cavity. This histological appearance persisted up to 2 years post-injection in horse joints. Intra-articular injection of PAAG results in a stable, long-lasting sub-synovial layer of gel traversed with thin strands of connective tissue. Further studies to explore potential effects on synovial inflammation and pain are warranted.
Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.
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Publication Date: 2016-07-30 PubMed ID: 27485850DOI: 10.1016/j.joca.2016.07.007Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research investigates the potential of Polyacrylamide hydrogel (PAAG), a safe and durable synthetic compound, in addressing symptoms of osteoarthritis (OA). The focus is on whether this substance integrates into joint lining both in normal and OA-enforced animal joints, and if this integration is sustainable.

Methodology

  • The experiment is a longitudinal study and a post mortem examination, comprising a total of 28 animal joints from rabbits and horses.
  • The first part of the study involves injecting PAAG into the knee joints of ten rabbits and following their condition for a year.
  • The second part involves a post mortem examination of 18 horse joints. These joints had previously received 1-2 injections of PAAG for clinically and radiologically diagnosed OA.

Results

  • The integration of the injected gel was visible as early as day 10 in the rabbit and by day 14 in the horse. This was evidenced by the proliferation and invasion of synovial cells into the gel.
  • By day 90 in rabbits and day 30 in horse joints, the gel had formed a sub-synovial layer. This layer was intertwined with thin strands of connective tissue and vessels, with a synovial lining facing the joint cavity.
  • This histological appearance was stable and sustained up to 2 years post-injection in horse joints.

Conclusion

  • PAAG injection results in a stable, long-lasting sub-synovial layer of gel intertwined with thin connective tissue strands.
  • The promising results of this study warrant further investigation into PAAG’s potential effects on synovial inflammation and pain, two critical factors in the treatment of osteoarthritis.

Cite This Article

APA
Christensen L, Camitz L, Illigen KE, Hansen M, Sarvaa R, Conaghan PG. (2016). Synovial incorporation of polyacrylamide hydrogel after injection into normal and osteoarthritic animal joints. Osteoarthritis Cartilage, 24(11), 1999-2002. https://doi.org/10.1016/j.joca.2016.07.007

Publication

Osteoarthritis and cartilage
ISSN: 1522-9653
NlmUniqueID: 9305697
Country: England
Language: English
Volume: 24
Issue: 11
Pages: 1999-2002
PII: S1063-4584(16)30189-3

Researcher Affiliations

Christensen, L
  • Department of Pathology, Herlev Hospital, University of Copenhagen, Denmark. Electronic address: lise.christensen.01@regionh.dk.
Camitz, L
  • Camitz Equestrian, Glumsoe, Denmark. Electronic address: Camitz@mail.dk.
Illigen, K E
  • Statens Serum Institut, Copenhagen, Denmark. Electronic address: KEI@ssi.dk.
Hansen, M
  • Hojgaard Horse Hospital, Fuen, Denmark. Electronic address: kontakt@hoejgaard-hestehospital.dk.
Sarvaa, R
  • Felina Cat Clinic, Copenhagen, Denmark. Electronic address: Dyredoktor@hotmail.com.
Conaghan, P G
  • Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds and NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK. Electronic address: P.Conaghan@leeds.ac.uk.

MeSH Terms

  • Acrylic Resins / therapeutic use
  • Animals
  • Horses
  • Injections, Intra-Articular
  • Joints
  • Longitudinal Studies
  • Prospective Studies
  • Rabbits
  • Synovial Membrane

Citations

This article has been cited 11 times.
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  7. Luedke LK, Seabaugh KA, Cooper BG, Snyder BD, Wimmer MA, McIlwraith CW, Barrett MF, Kawcak CE, Grinstaff MW, Goodrich LR. A Safety and Efficacy Study of a Synthetic Biolubricant in an Equine Model of Post-Traumatic Osteoarthritis. Animals (Basel) 2025 Feb 1;15(3).
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  9. Bliddal H, Beier J, Hartkopp A, Conaghan PG, Henriksen M. Effectiveness and safety of polyacrylamide hydrogel injection for knee osteoarthritis: results from a 12-month follow up of an open-label study. J Orthop Surg Res 2024 May 2;19(1):274.
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  10. Wathier M, Lakin BA, Cooper BG, Bansal PN, Bendele AM, Entezari V, Suzuki H, Snyder BD, Grinstaff MW. A synthetic polymeric biolubricant imparts chondroprotection in a rat meniscal tear model. Biomaterials 2018 Nov;182:13-20.
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