BACKGROUND:Matrix metal oproteinases (MMPs) have been shown to break the balance between the production and degradation of extracel ular matrix by degrading col agen, gelatin, elastin and other macromolecules, which is the leading cause of bone and cartilage damage in rheumatic arthritis.
OBJECTIVE:To determine the expression levels of MMP-2 and MM-9 in the rabbit knee osteoarthritis cartilage, and to analyze whether they are related to the early MRI performance.
METHODS:Fifty healthy Japanese white rabbits free from osteoarthritis were enrol ed and randomly divided into control group (n=10) and model group (n=40). The anterior and posterior cruciate ligament amputation was adopted to establish the model of osteoarthritis. Subsequently, MRI examination and the expression levels of MMP-2 and MMP-9 were detected at 1, 3, 5 and 7 weeks (n=10 at each time point), respectively.
RESULTS AND CONCLUSION:MRI examination showed that more damaged cartilage appeared with time in the rabbit model of osteoarthritis, and significantly different from MRI classification (P<0.05). The expression levels of MMP-2 and MMP-9 mRNA in the model group were always significantly higher than those in the control group (P<0.05);MMP-2 level reached the highest at 3 weeks after modeling (P<0.01), and then presented a slight decline;MMP-9 level peaked at 5 weeks after modeling (P<0.01) and slightly decreased at 7 weeks. MRI classification of cartage injury and expressions of MMP-2 (R2=0.119, P=0.119) and MMP-9 (R2=0.466, P=0.466) were shown to have the correlation. These results il ustrate that the serum levels of MMP-2 and MMP-9 are related to the early destruction of articular cartilage in patients with osteoarthritis, and can be used as predictors for early osteoarthritis.

Objective:To evaluate the effect of autologous platelet plasmapheresis (APP) and reinfusion on acute kidney injury (AKI) after total aortic arch replacement.Methods:Sixty American Society of Anesthesiologists physical status Ⅲ or Ⅳ patients of both sexes, aged 18-64 yr, with body mass index of 19-34 kg/m 2, scheduled for total aortic arch replacement under general anesthesia, were divided into 3 groups( n=20 each)using a random number table method: APP-reinfusion group (group A), acute normovolemic hemodilution (ANH) group (group N) and autologous blood withdrawal-reinfusion group (group C). In group A, APP was completed before the operation, concentrated red blood cells were transfused timely according to the intraoperative conditions, and platelet-poor and platelet-rich plasma were transfused after protamine neutralization.In group N, ANH was completed before the operation, and the whole blood released was transfused after protamine neutralization.Autologous blood withdrawal and washed red blood cell (RBC) transfusion were only performed in group C, and autologous blood withdrawal was performed in group A and group N. Cervical venous blood and urine samples were collected at 10 min after anesthesia induction (T 1), at 5min after cardiopulmonary bypass (T 2), immediately after the end of surgery (T 3), at 24h and 48h after surgery (T 4、5) for determination of the concentrations of hematocrit (Hct), plasma free hemoglobin (fHb), urinary neutrophil gelatinase-associated lipocalin (NGAL), tissue metalloproteinase-inhibitor -2 (TIMP-2) and insulin-like growth factor binding protein-7 (IGFBP-7) and for calculation of [TIMP-2]×[IGFBP-7]. Glomerular filtration rate (GFR) and concentrations of reatinine (Scr), urea, uric acid and cystatin C were measured before surgery, on the right postoperative day, and at 1, 2 and 3 days after surgery.The intraoperative requirements for allogeneic blood product transfusion, postoperative mechanical ventilation time, duration of intensive care unit (ICU) stay and hemodialysis were recorded. Results:Compared with group C, the postoperative requirement for allogeneic RBC transfusion in group A and group N and the allogeneic platelet transfusion in group A were significantly reduced, Hct at T 2 in group N was decreased, fHb at T 3 and T 4 in groups N and group A was decreased, Scr concentration on the right postoperative day and at 1 day after operation in group A was decreased, and cystatin C concentration on the right postoperative day and at 2 and 3 days after operation in group A was decreased ( P<0.05). Compared with group N, the postoperative requirement for the allogeneic platelet transfusion, concentrations of NGAL and TIMP-2 at T 3-5, IGFBP-7 concentration and [TIMP-2]×[IGFBP-7] at T 3 and T 4, Scr concentration on the right postoperative day and at 1 day after operation and cystatin C concentration on the right postoperative day and at 2 and 3 days after operation were significantly decreased in group A ( P<0.05). Conclusion:APP-reinfusion provides better efficacy in alleviating postoperative AKI than ANH in the patients undergoing total aortic arch replacement.