LABORATORY AND ANIMAL STUDIES

Experimental Study for the Effects of Polysaccharide Sulfate (PSS) on the Prevention of Steroid-induced Osteonecrosis
L Huang, T Dong
Department of Orthopaedic Surgery, The First Teaching Hospital of Soochow University, Soochow, China

Purpose: To investigate the preventive effect of PSS on the steroid-induced osteonecrosis in high risk group.

Method: 24 adult health rabbits were divided into two groups: Group A consisted of 14 rabbits that received 10ml/kg of sterile horse serum intravenously twice at three-week intervals, two-weeks after the second serum injection, they were treated with an intraperitoneal injection of 10mg/kg/day of dexamethasone for 3 consecutive days. Group B, PSS treated group, consisted of 10 rabbits that began to receive 50mg/day PSS orally on the day dexamethasone injected for 4 weeks, when being treated with combination of horse serum and dexamethasone like Group A. Serological tests (CHOL, TG, HDL-C, LDL-C, Lp(a), APTT, PT, TT, Fbg and AT-?, TXB2,6-Keto-PGF1a, t-PA, PAI, D-dimer) were measured before and 24 hours, 4 weeks after the final treatment. Meanwhile, the histopathological changes of the liver, heart, kidney, lung and the bone samples were observed under microscope, and the diameter of the largest fat cell intraosseous was measured, the rate of osteonecrosis occurrence of each group was calculated. The percentage of the bone area and fat area of the femoral head under microscope in both groups were evaluated by computer, then compared with each other to find the difference of them.

Results: CHOL, TG, LDL-C and TXB2, PAI, D-dimer levels of Group B with PSS were lower than that of Group A, while AT-? and t-PA levels of Group B were higher than that of Group A. On the other hand, the rate of osteonecrosis occurrence 20% Vs 71.43%?, the diameter of the largest fat cell?29.84µm Vs 45.54µm?and the percentage of fat area of the femoral head?16.35% Vs 30.45%?of Group B were lower than that of Group A, while the percentage of bone area?45.57% Vs 36.64%?of Group B was higher than that of Group A. (P?0.05).

Conclusion: PSS has the effect of lowing the blood lipid, increasing the ability of anti-coagulation and increasing the activity of fibrinolysis. PSS may have certain effect on prevention of steroid-induced osteonecrosis.