Fig. 4. Correlation analyses between the number of circulating EPCs and SOD or MDA. Circulating EPCs were weakly to moderately correlated with SOD levels at day 7 (A) and with MDA levels at day 7 (B) post mild TBI. EPC, endothelial progenitor cell; SOD, superoxide dismutase; MDA, malonyldialdehyde; TBI, traumatic brain injury.