Effects of Tanshinone IIA in Adult Rats after SCI Figure 2. Effects of TIIA on histological changes at 24 h after SCI. Normal structure of spinal cord was observed in the sham (A) and sham/ TIIA (B) groups at 24 h after SCI. A significant damage of spinal cord was shown by the presence of edema, haemorrhage and loose structure tissue at 24 h after SCI (C). A significant protective effect of TIIA (20 mg/kg) was observed in the SCI/TIIA group (D). wm: white matter; gm: gray matter. The histological score was accessed in a blinded manner (E). MPO activity in tissues was significantly increased at 24 h in the SCI group compared with the sham and sham/TIIA groups and was decreased with the treatment of TIIA (F). Bars represent means 6 SEM. **p,0.001 vs. sham group, #p,0.05 vs. SCI group. doi:10.1371/journal.pone.0038381.g002 Hospital, Xi’an, China) to characterize the spinal cord injury, and the slices were scored for edema, neutrophil infiltration, and hemorrhage. A scale of 0–4 represents the severity of spinal cord injury: 0 for none or minor, 1 for modest or limited, 2 for intermediate, 3 for widespread or prominent, and 4 for widespread and most prominent [26]. These tasks were conducted in a blinded manner, so that investigators were not able to identify the treatment and outcome of the animal until the completion of the measurement. Myeloperoxidase activity assay The myeloperoxidase (MPO) activity, an indicator of polymor- phonuclear leukocyte accumulation, was determined in the spinal cord tissue as previously described [27]. The extracted injured tissues from rats of all groups (n = 4 for each group) were weighed at 24 h after SCI, and the myeloperoxidase activity was measured. Each tissue sample was homogenized in homogenate medium [0.5% (w/v) hexadecyltrimethyl-ammonium bromide dissolved in 10 mM potassium phosphate buffer (pH 7)] and centrifuged at 20,0006g for 30 min at 4uC. An aliquot of the supernatant was subsequently incubated with a solution of 1.6 mM tetramethyl- Figure 3. Effects of TIIA on the activation of astrocytes at 24 h after SCI. Few positive staining cells for GFAP were observed in the spinal cord tissues collected from the sham (A) and sham/TIIA (B) groups. A significant increase of GFAP positive cells was found in tissue from the SCI group at 24 h after injury (C). A significant reduction of GFAP positive cells was observed in the SCI/TIIA group (D). Analysis of the amount of GFAP showed the similar results (E). Bars represent means 6 SEM. **p,0.001 vs. sham group, # p,0.05 vs. SCI group. doi:10.1371/journal.pone.0038381.g003 PLoS ONE | www.plosone.org 3 June 2012 | Volume 7 | Issue 6 | e38381