Fig. 1

The levels of Hb in herniated nucleus pulposus are higher than those in nonherniated nucleus pulposus, as determined by MALDI-TOF MS. a MS spectra of total protein lysates measured by a high-mass detector. The tissue sample was obtained from the patient 24 in Table 1. b The spectra of Hb standard (1), tissue lysates (2), and a standard and lysate mixture (3) measured by the high-mass detector. The tissue sample was obtained from the patient 23 in Table 1. c The spectra of tissue lysates from herniated nucleus pulposus and nonherniated nucleus pulposus measured by a high-mass detector. The tissue samples were obtained from the patients 14 and 4 in Table 1. d Scatter plot of the Hb-related peak intensity in 13 samples of herniated nucleus pulposus and 9 samples of nonherniated nucleus pulposus as measured by a high-mass detector. The data were analyzed with GraphPad Prism 5.02 software. **P < 0.01. e The PCA clustering diagram of 13 samples of herniated nucleus pulposus and 9 samples of nonherniated nucleus pulposus. f ROC curve analysis of 6 Hb-related peaks in 13 samples of herniated nucleus pulposus and 9 samples of nonherniated nucleus pulposus