OBJECTIVE: To evaluate the impact of forced joint exercise following acute knee injury on lubricin metabolism and its relationship to cartilage degeneration and to assess chondroprotection of a single-dose purified human lubricin injection in exercised injured joints. METHODS: Anterior cruciate ligament transection (ACLT) was performed in rats with six experimental groups; 3-week post-ACLT, 3-week post-ACLT + exercise, 5-week post-ACLT, 5-week post-ACLT + exercise, and 5-week post-ACLT + exercise treated with intra-articular phosphate buffered saline (PBS) or lubricin. Joint exercise was achieved using a rotating cylinder at a speed of 6 rpm for 30 min daily, 5 days a week starting 1 week following surgery. Cartilage lubricin expression in injured joints was determined. Histological analyses included Safranin O/Fast Green, activated caspase-3, and lubricin mRNA in-situ hybridization. Assessment of cartilage damage was performed by osteoarthritis research society international (OARSI) modified Mankin scoring and urinary CTXII (uCTXII) levels. RESULTS: At 3 weeks, lubricin expression in exercised ACLT joints was significantly (P < 0.001) lower compared to ACLT joints. The OARSI scores were significantly (P < 0.001) higher in the ACLT + exercise animals compared to ACLT animals at 5 weeks. Compared to 3-week ACLT, 3-week ACLT + exercise cartilage showed increased caspase-3 staining. Compared to ACLT + exercise and PBS-treated ACLT + exercise, lubricin intra-articular treatment resulted in a significant increase (P < 0.001) in cartilage lubricin gene expression and a reduction (P < 0.05) in uCTXII levels. CONCLUSION: Joint exercise resulted in decreased lubricin cartilage expression, increased cartilage degeneration and reduced superficial zone chondrocyte viability in the ACLT joint. Intra-articular lubricin administration ameliorated cartilage damage due to exercise and preserved superficial zone chondrocytes' viability.
OBJECTIVE: To evaluate the impact of forced joint exercise following acute knee injury on lubricin metabolism and its relationship to cartilage degeneration and to assess chondroprotection of a single-dose purified humanlubricin injection in exercised injured joints. METHODS: Anterior cruciate ligament transection (ACLT) was performed in rats with six experimental groups; 3-week post-ACLT, 3-week post-ACLT + exercise, 5-week post-ACLT, 5-week post-ACLT + exercise, and 5-week post-ACLT + exercise treated with intra-articularphosphate buffered saline (PBS) or lubricin. Joint exercise was achieved using a rotating cylinder at a speed of 6 rpm for 30 min daily, 5 days a week starting 1 week following surgery. Cartilagelubricin expression in injured joints was determined. Histological analyses included Safranin O/Fast Green, activated caspase-3, and lubricin mRNA in-situ hybridization. Assessment of cartilage damage was performed by osteoarthritis research society international (OARSI) modified Mankin scoring and urinary CTXII (uCTXII) levels. RESULTS: At 3 weeks, lubricin expression in exercised ACLT joints was significantly (P < 0.001) lower compared to ACLT joints. The OARSI scores were significantly (P < 0.001) higher in the ACLT + exercise animals compared to ACLT animals at 5 weeks. Compared to 3-week ACLT, 3-week ACLT + exercise cartilage showed increased caspase-3 staining. Compared to ACLT + exercise and PBS-treated ACLT + exercise, lubricinintra-articular treatment resulted in a significant increase (P < 0.001) in cartilagelubricin gene expression and a reduction (P < 0.05) in uCTXII levels. CONCLUSION: Joint exercise resulted in decreased lubricincartilage expression, increased cartilage degeneration and reduced superficial zone chondrocyte viability in the ACLT joint. Intra-articularlubricin administration ameliorated cartilage damage due to exercise and preserved superficial zone chondrocytes' viability.
Authors: Katherine M Larson; Ling Zhang; Khaled A Elsaid; Tannin A Schmidt; Braden C Fleming; Gary J Badger; Gregory D Jay Journal: J Orthop Res Date: 2017-03-02 Impact factor: 3.494
Authors: Elizabeth Feeney; Bridgette T Peal; Jacqueline E Inglis; Jin Su; Alan J Nixon; Lawrence J Bonassar; Heidi L Reesink Journal: J Orthop Res Date: 2019-03-28 Impact factor: 3.494
Authors: Mark Hurtig; Iman Zaghoul; Heather Sheardown; Tannin A Schmidt; Lina Liu; Ling Zhang; Khaled A Elsaid; Gregory D Jay Journal: J Orthop Res Date: 2018-12-17 Impact factor: 3.494
Authors: Kimberly A Waller; Ling X Zhang; Khaled A Elsaid; Braden C Fleming; Matthew L Warman; Gregory D Jay Journal: Proc Natl Acad Sci U S A Date: 2013-03-25 Impact factor: 11.205