Fig. 4

In vivo fluorescent image after IA injection of CAPP, TKP or TKCP probes to detect the level of ROS induced by MIA in C57BL6/J knees. a The up-regulated ROS activity in the OA joints was reflected by fluorescent signal and measured by an in vivo imaging system at selected time points after IA-injection. Ex: 630 nm, Em: 700 nm. b The relative fluorescence intensity of TKCP, CAPP or TKP probes at different treatment times. c Representative photographs showed the macroscopic appearance of the cartilage from the femoral condyles and in vivo NIR bioimaging indicated the level of ROS via the fluorescent intension according to the development of OA. d Analysis of the macroscopic score and relative fluorescent intensity to evaluate the severity of OA. (n = 3; ean ± SD; *, # indicate p < 0.05, **; ## indicate p < 0.01; ***, ### indicate p < 0.001.)