Matrix metalloproteinase activity in stifle synovial fluid of cranial cruciate ligament deficient dogs and effect of postoperative doxycycline treatment.

This prospective clinical study investigated the activity of matrix metalloproteinases (MMPs) in stifle synovial fluid (SF) of 13 dogs with acute cranial cruciate ligament (CCL) rupture, and the effect of a postoperative doxycycline treatment. MMP-2, 3, 9 and 13 activities were compared with respect to the time of sampling (preoperatively or 1 month after surgical stabilisation) and the type of postoperative adjuvant treatment (doxycycline or not). No significant activity was detected for both MMP-3 and MMP-13. MMP-2 and MMP-9 activities were found to be significantly highly increased in SF of CCL ruptured stifles compared to control stifles of unaffected dogs. No significant effect from surgical stabilisation and postoperative doxycycline treatment on MMP-2 and MMP-9 activities was found, indicating that doxycycline may not be an appropriate postoperative medical treatment after CCL rupture.

Expression of MMP-1 in cartilage and synovium of experimentally induced rabbit ACLT traumatic osteoarthritis: immunohistochemical study.

UNLABELLED: To observe the level and the distribution of MMP-1 in cartilage and synovium over the progression of OA in rabbit ACLT model, and to explore the relationship between the amount of MMP-1 expression and the degree of OA cartilage degradation. OA was induced in 20 rabbits by anterior cruciate ligament transection (ACLT) and ten rabbits were killed at 4 and 8 weeks after the operation, respectively. A further ten rabbits received unilateral knee arthrotomy as controls. Cartilage degradation was observed under dissecting microscope, immunohistochemical, and morphometric analysis were adopted to record the tissue level and distribution of MMP-1 in cartilage and synovium. Cartilage degradation in both ACLT groups was more severe than that in control group, and the degradation in 8-week ACLT group was more severe than that in 4-week ACLT group. MMP-1 was expressed predominantly in the superficial and upper intermediate layers of cartilage and in the lining layer of synovium. Its expression was increased steadily over the progression of OA both in cartilage and in synovium, but there was a little difference in the increase pattern between them: increase of MMP-1 in synovium lagged behind that in cartilage in early stage of OA. CONCLUSION: MMP-1 was involved in OA development in rabbit ACLT model and the amount of its expression was related with the degree of cartilage degradation. The increase of MMP-1 expression in synovium lagged behind that in cartilage, suggesting OA pathology was originated from cartilage, but synovitis may also paticipate in cartilage degradation, especially in middle and late stage of OA.

Apoptosis of ligamentous cells of the cranial cruciate ligament from stable stifle joints of dogs with partial cranial cruciate ligament rupture.

OBJECTIVE: To describe the presence and amount of apoptotic ligamentous cells in different areas of partially ruptured canine cranial cruciate ligaments (prCCLs) and to compare these findings with apoptosis of ligamentous cells in totally ruptured cranial cruciate ligaments (trCCLs). ANIMALS: 20 dogs with prCCLs and 14 dogs with trCCLs. PROCEDURES: Dogs with prCCLs or trCCLs were admitted to the veterinary hospital for stifle joint treatment. Biopsy specimens of the intact area of prCCLs (group A) and the ruptured area of prCCLs (group B) as well as specimens from trCCLs (group C) were harvested during arthroscopy. Caspase-3 and poly (ADP-ribose) polymerase (PARP) detection were used to detect apoptotic ligamentous cells by immunohistochemistry. RESULTS: No difference was found in the degree of synovitis or osteophytosis between prCCLs and trCCLs. No difference was found in degenerative changes in ligaments between groups A and B. A substantial amount of apoptotic cells could be found in > 90% of all stained slides. A correlation (r(s) = 0.71) was found between the number of caspase-3-and PARP-positive cells. No significant difference was found in the amount of apoptotic cells among the 3 groups. No significant correlation could be detected between the degree of synovitis and apoptotic cells or osteophyte production and apoptotic cells. CONCLUSIONS AND CLINICAL RELEVANCE: The lack of difference between the 3 groups indicates that apoptosis could be a factor in the internal disease process leading to CCL rupture and is not primarily a consequence of the acute rupture of the ligament.

Intra-articular injection of hyaluronate and indomethacin in rabbits with antigen-induced arthritis.

Combined effects of hyaluronate and indomethacin in the treatment of rabbits with antigen-induced arthritis (AIA) were evaluated by assessing joint swelling, C-reactive protein (CRP) and prostaglandin E(2) (PGE(2)) levels with periodic intra-articular (ia) injections of hyaluronate alone (HA group) and with either a low or high concentration of indomethacin (LI-HA or HI-HA group). End-point analyses included matrix metalloproteinases-3 (MMP-3) activity and macroscopic and histological joint examinations. Results demonstrated that treatment in LI-HA and HI-HA groups resulted in statistically significant suppression of CRP, PGE(2, )and MMP-3 in comparison with those of HA group. Inhibition of serum CRP was only observed in LI-HA group. The order of serum MMP-3 inhibition was LI-HA>HI-HA>HA. Based on macroscopic and histological analyses of pannus formation, hyperplasia, inflammation, joint leakage and erosion, and loss of proteoglycan, the only statistically significant improvement was shown in LI-HA group compared to HA group and HI-HA group compared to control group.

Matrix metalloproteinases and aggrecanases cleave aggrecan in different zones of normal cartilage but colocalize in the development of osteoarthritic lesions in STR/ort mice.

OBJECTIVE: To map aggrecan cleavage by matrix metalloproteinases (MMPs) and aggrecanases in normal murine tibial articular cartilage (CBA strain) and in the development of spontaneous osteoarthritis (OA) in the STR/ort mouse and to assess the influence of sex hormone status on these conditions in gonadectomized STR/ort mice. METHODS: The distributions of neoepitopes of aggrecan generated by MMP (VDIPEN) and aggrecanase (NITEGE) cleavage were investigated by immunohistochemistry. RESULTS: VDIPEN neoepitope was detected mainly in the pericellular matrix of deep-zone chondrocytes in normal tibial cartilage from STR/ort and CBA mice. In early OA, VDIPEN immunostaining also localized to the pericellular matrix of chondrocytes at the site of the lesion. With increasing severity of OA lesions, VDIPEN immunostaining was also detected in the interterritorial matrix, close to the site of the lesion. In contrast, NITEGE mapped most strongly to the pericellular matrix of upper-zone chondrocytes in normal tibial cartilage. As with VDIPEN, NITEGE was strongly expressed in the pericellular matrix at the site of early OA lesions. With advancing OA, NITEGE colocalized with VDIPEN in both the pericellular and interterritorial matrices of chondrocytes adjacent to OA lesions and in those of the deep zones. Hormone status did not appear to influence the development of OA or the distribution of aggrecan neoepitopes in STR/ort mice. CONCLUSION: MMP- and aggrecanase-generated neoepitopes map predominantly to different regions in normal murine tibial cartilage. However, both groups of enzymes generate increased amounts of neoepitopes in pericellular and interterritorial matrix adjacent to histopathologic lesions of OA. Aggrecan degradation and the development of OA appear to be independent of sex hormone status in this model.