Fig. 2.

EPR imaging showed increased pO₂ after PEGPH20 treatment. EPR imaging was performed in BxPC3-HAS3 tumor bearing mice treated with control buffer or PEGPH20 (n = 7 each group) before (before the first injection on day 0) and after treatment (3 h after the 2nd PEGPH20 injection on day3). A, Representative oxygen map obtained by EPR imaging and T2-weighted anatomical image. B, Histograms of pO₂ distribution within the tumor of each group. C and E, The mean pO₂ of each tumor before and after treatment are shown by treatment group. Individual values are shown. D and F, pO₂ change (%) from the baseline (pre-treatment) of each group. Data are shown as mean ± SE. G and H, Histological assessment of pimonidazole staining. BxPC3-HAS3 tumors treated with control buffer or PEGPH20 were surgically resected 3h after the 2nd PEGPH20 injection on day3. Frozen sections of tumors were stained for exogenous hypoxia marker pimonidazole (pimo). G, Representative pimo staining of each group (scale bar = 1mm). H, Quantification of pimo positive area. I, Comparison of ΔHF10 between control and PEGPH20 groups evaluated by EPR imaging. Data are shown as mean ± SE (n = 5 per group). Statistical significance between groups was determined by paired t-test for C and by Student's t-test for D and F. *p < 0.05, **p < 0.01, ***p < 0.001 ****p < 0.0001.