Experimental Study Correlation Between MRI-IVIM And MVD,VEGF In Rhabdomyosarcoma Murine Model

Objective: To investigate the correlation between the Standard ADC value,D value,D* value and f value from IVIM and MVD or VEGF in the mouse model of rhabdomyosarcoma.Materials and Methods: 1.Experimental materials 1.1 Experimental animals Female Balb/c nude mice,22,4-6 weeks old 1.2 Experimental cell line Human embryonal rhabdomyosarcoma cell line RD 1.3 experimental reagents High glucose DMEM medium,Cyan streptomycin,CD34 antibody,VEGF antibody.1.4 experimental equipment Cell incubator,3.0T MR scanner,Microscope.2.Experimental methods 2.1 Establishment of rhabdomyosarcoma mouse models Rhabdomyosarcoma cells were cultured in DMEM complete medium,and cells in logarithmic phase were collected and inoculated subcutaneously on the right back of nude mice.2.2 MR imaging and post-image processing in mouse model of rhabdomyosarcoma The mouse model of rhabdomyosarcoma was examined by T1 WI,T2WI and IVIM.Standard ADC,D,D* and f pseudo-color diagrams were obtained by Functool software of GE ADW 4.7 workstation.ROI was selected from the highest point of the signal on the original IVIM diagram to obtain the corresponding parameter values,and the average value of the three measurements was taken as the final result.2.3 MRI-pathological comparison method in mouse model of rhabdomyosarcoma After anesthesia,the mice were marked on the body surface,followed by MRI examination.After the examination,the tumor was completely removed and fixed in formalin solution for 8 hours.2.4 HE section staining and observation in mouse model of rhabdomyosarcoma HE sections were obtained through xylene dewaxing,gradient alcohol rehydration,hematoxylin staining,hydrochloric acid alcohol differentiation,eosin restaining,gradient alcohol dehydration,xylene transparency and neutral resin sealing.The observation range was selected from HE staining sections,and the observation was carried out under low power,medium power and high power respectively.2.5 immunohistochemical staining and observation of results in mouse model of rhabdomyosarcoma The slices were baked in the oven,and then the slices were successively dewaxed with xylene,rehydrated with gradient alcohol,repaired with antigen,added with an appropriate amount of primary antibody for immune reaction,stained with hematoxylin,dehydrated with gradient alcohol,sealed with xylene and sealed with neutral gum to obtain immunohistochemical slices.The results of MVD count and VEGF expression were obtained by observing slices under 200 times microscope.3.Observe indicators 3.1 Establishment of rhabdomyosarcoma mouse model 3.2 MRI findings in mouse model of rhabdomyosarcoma 3.3 Histopathological findings in mouse model of rhabdomyosarcoma 4.Statistical methods SPSS 24.0 software was used to analyze the data.P<0.05 was considered statistically significant.If the counting data were normally distributed,Pearson test was performed for the correlation analysis of Standard ADC value,D value,D* value and f value with MVD count and VEGF expression,respectively.If the counting data were non-normal distribution,Spearman test was performed on the correlation analysis.Results: 1.Establishment of rhabdomyosarcoma mouse model The time of tumor formation in 22 mouse models of rhabdomyosarcoma was 7-15 days.The tumor volume reached its maximum at 46-60 days after tumor cell inoculation,with the maximum diameter of 12.0-20.0 mm and volume of 807.36-2220.10 mm3.2.MRI findings in mouse model of rhabdomyosarcoma 2.1 conventional MRI findings The tumor was located subcutaneously on the right back of nude mice,showing uniform or slightly high signal on T1 WI,uniform high signal on T2 WI,and higher signal on speckle in some of them.2.2 IVIM findings IVIM in 22 mouse models of rhabdomyosarcoma showed high signal.The mean Standard ADC value,D value,D* value and f value of rhabdomyosarcoma mouse models were 1.068±0.232×10-3mm2/s,0.705±0.075×10-3mm2/s,5.920±1.815×10-3mm2/s and 0.172±0.070,respectively.3.The pathology of rhabdomyosarcoma in mouse models 3.1 Routine pathological manifestation Gross pathological examination revealed that the tumor was round or irregular in shape,with graying and tough texture on all sections.Microscopically,the tumor cells were found to have uneven distribution,irregular necrotic areas,small round or oval cells,large hyperchromatic nuclei,and little cytoplasm.3.2 MVD count and VEGF expression Immunohistochemical staining of CD34 in 22 cases of rhabdomyosarcoma showed the brown-yellow color of vascular endothelial cells,and the expression of VEGF in cytoplasm or intercytoplasm was brown-yellow.The mean MVD count was 21.91±9.47,and the mean VEGF expression was 20.33±7.89%,with a moderately positive correlation between MVD and VEGF expression.4.The correlation between IVIM parameters and MVD or VEGF in the mouse model of rhabdomyosarcoma 4.1 The correlation between IVIM parameters and MVD There was a moderately positive correlation between D* and MVD,with statistical significance(P < 0.05).There was no correlation between the values of IVIM-Standard ADC value,D value and f value and MVD in the mouse model of rhabdomyosarcoma.4.2 The correlation between IVIM parameters and VEGF expression D* showed a moderately positive correlation with VEGF,which was statistically significant(P < 0.05).There was no correlation between the values of IVIM-Standard ADC value,D value and f value and VEGF in the mouse model of rhabdomyosarcoma.Conclusions: On the basis of MRI-pathological comparison,correlation analysis of IVIM parameters with MVD and VEGF in 22 mouse models of rhabdomyosarcoma was conducted,and the following conclusions can be drawn: 1.The D* value of IVIM parameter in the mouse model of rhabdomyosarcoma was positively correlated with MVD,that is,with the increase of D* value,the pathological MVD increased,and otherwise decreased.Standard ADC value,D value and f value have no correlation with MVD in the mouse model of rhabdomyosarcoma.2.The D* value of IVIM parameter in the mouse model of rhabdomyosarcoma was positively correlated with MVD,that is,the expression of VEGF increased with the increase of D* value,and decreased with the increase of D* value.There was no correlation between the Standard ADC value,D value and f value and VEGF in the mouse model of rhabdomyosarcoma.