SOD makes the first line of defense against free radicals attacks by catalyzing the dismutation of superoxide anion (O2) into hydrogen peroxide (H2O2) and molecular oxygen (O2). SOD level was
assayed on the 21st day in the different groups as shown in Fig. 5a. A significant decrease (p < 0.001) in SOD activity was found in joints of CIA rats as compare to control. SOD activity was significantly increased (p < 0.001) in the group receiving 5 ppm of Cd as
compared to a CIA group whereas at 50 ppm of Cd, a significant decreased (p < 0.001) in SOD activity was noted as compared to CIA.