Objective To investigate the effect of sodium hyaluronate (SH) intra-articular injection on the treatment of knee osteoarthritis (OA), andto compare the contents of free radicals and inflammatory factors in joint fluids of pre-and pro-treatment as to explore the treatment mechanism of SH. Methods Ninety-two patients (111 knees) with mild(51)，moderate(35) and serious(25) knee OA were treated with intra-articular injections of SH (20 mg once a week for 5 weeks). According to Lysholm scoring, clinical signs such aspain, swelling,and the ability to walk, squat, run, go upstairs and downstairs were assessed before and after the treatment, and the contents of nitric oxide (NO), superoxide dismutase(SOD), malonic dialdehyde(MDA) and IL-1β、TNF-α in joint fluids from the OA joints before 1st,2nd, and 5th injection and 3 months after each injection were observed. Results All cases were followed up for 3 months. The improvements in the signs and function of knees were excellent in 42 knees, good in 38 knees, fair in 21 knees and poor in 10 knees, with 72.1% excellent and good results. The lighter the illness was, the better the improvement was: the rate of the excellent and good was 92.1% in mild group, 68.6% in moderate group and 42.9% in serious group. The contents of oxygen free radicals and IL-1β、TNF-α of the patients with mild and moderate OA decreasedmarkedly after being treated with SH（Plt;0.05）, but these decreased lightlyin serious OA group（Pgt;0.05）. SH had mild effect on the contents of NO. Three months after treatment, only in mild OA group the contents of NO significantly decreased（Plt;0.05）, and no significant change in moderate and serious groups was observed（Pgt;0.05）. Conclusion SH intraarticular injection has a positive effect on the relief of clinical symptoms and on the improvement of articular function of knee OA. The therapeutical effect of SH on OA is achieved possibly by decreasing the contents of free radicals especially oxygen free radicals and inflammatory factors in joint fluids.
Perfusion of free flaps from groin of rabbits, after 12 hours of complete ischemia, with superoxide dismutase (SOD), an oxygen free radical scavenger, would significantly increase the survival rate of these flaps from 18.75% to 75% in the control group. Tissue levels of SOD and malonydialdehyde (MDA, an end product of lipoperoxidation) were measured before ischemia, after ischemia but before reperfusion, and 60 minites after reperfusion. In untreated flap, after 12 hours- ischemia, the SOD content of skin decreased significantly as compared with the SOD content before ischemia, and reperfusion further decreased SOD activity, while the concentration of MDA increased after ischemia and further increased after reperfusion. In the treated flaps, the concentration of SOD was not decrease and MADnot increased after reperfusion. There was a negative correlation between the values of SOD and MDA. These findings suggested that free oxygen radicals playedan important role in the free flap ischemia reperfusion injury. SOD could increase the survival of ischemic free-flaps by reducing lipoperoxidation. The results had significant clinical implications with regard to organ preservation and transplantation.