| Objective:Using dynamic contrast-enhanced MRI (DCE-MRI) to monitor early response of colon cancer xenografts in nude mice. To explore the feasibility and value of DCE-MRI parameters were used to assessing early effects of vascular-targ-eted therapy for tumors. Methods:Thirty six nude mice were injected subcutaneou-sly with human colon cancer cells HT-29 to the right hind leg. The nude mice w-ere evenly divided into anti-angiogenesis drug group (n=12), tumor vascular-disrupti-ng agent group (n=12) and control group (n=12). The experiment groups were trea-ted with bevacizumab 10mg/kg, combretastatin 100mg/kg and the control group wi-th the same dose of normal saline. DCE-MRI was performed before medication an-d 1h,24h and 48h after medication. The Ktrans, Kep, Ve and iAUC of DCE-MR-I were analyzed by using Siemens tissue 4D perfusion software, Then every two t-umors were harvested and underwent pathology examination each time, including HE stain-ing and microvessel density (MVD). The DCE-MRI parameters were anal-yzed using repeated measures analysis of variance (RMANOVA). The Pearson corre-lation coefficient was used to analyze the correlation between parameters of DCE-MRI and MVD. Results:(1) Under DCE-MRI, the edge of subcutaneous colon ca-ncer xenografts was obviously gradually enhanced, pseudo color indicated high perf-usion, the strength degree of the central region was low and which meant low per-fusion. (2) The differences in Ktrans and Kep values of different time in bevacizu-mab group and combretastatin group were statistically significant (F=4.849,21.116 and F=9.255,61.396, P<0.05). The Ktrans was no significant difference (F=0.633, P=0.600) and the Kep there was significant difference in control group (F=4.536, P=0.011). (3) There was no significant difference in Ktrans and Kep before medica-tion in different group (F=0.855 and 1.548, all P>0.05). There were significant di-fference in Ktrans and Kep 1h 24h 48h after medication (F1h=36.551 and 67.616, F24h=11.163 and 108.884, F48h=17.053 and 8.760, all P<0.05) between different gr-oups. (4) The Ve value of bevacizumab group had significant difference in differen-t times (F=3.592, P=0.0245). There were significant difference of the Ve and iAU-C at 24h after medication between different groups (F=5.602 and 3.810, all P<0. 05). (5) MVD of experimental groups were lower than of control group. Ktrans an-d Kep were positively correlated with MVD (r=0.640 and 0.257, P<0.05). Ktrans and Kep/iAUC values were positively correlated (r=0.663 and 0.705,.P<0.05). Con-clusion:Ktrans and Kep of DCE-MRI were sensitive to monitor the change of mi-crocirculation perfusion and capillary permeability. Ktrans and Kep were positively correlation with the MVD, may be used in monitoring the earlier effects of vascul-ar-targeted agents in targeted therapy for colon cancer. |
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