Preliminary Study On Effects Of Microwave Ablation Of Normal Muscle Combined With Celecoxib On Cell Proliferation And Blood Perfusion Of Distant VX2 Implanted Tumor

Part Ⅰ Establishment and biological characteristics of VX2 tumor model in rabbit paraspinal muscleObjective:To establish a VX2 tumor model of rabbit paraspinal muscle and observe its biological characteristics.Materials and Methods:VX2 tumor tissue mass were implanted into the paraspinal muscles of 15 New Zealand white rabbits by CT-guided percutaneous puncture.CT scans and enhanced CT scans were performed on the 14th,21st,28th,and 35th day after inoculation,and one tumor-bearing rabbit was randomly selected and sacrificed for gross anatomy and pathology.Results:VX2 tumor tissue mass were successfully implanted into the paraspinal muscles of the 15 rabbits by CT-guided percutaneous puncture.Paraspinal muscle VX2 tumors were successfully modeled in 14 rabbits,and the tumor formation rate was 93.3%.The CT scan of the paraspinal muscle VX2 tumor was a low-density nodule with blurred edges.CT-enhanced scan lesions were ring-enhanced,with blurred edges and low-density necrotic areas in the center.The paraspinal muscle VX2 tumors grew rapidly and there was a statistical difference between the TGRs at different time points(P=0.004).The size of the tumor was 1.0-2.5cm on the 14th to 28th day after VX2 tumor tissue implantation.There was a statistically significant difference in the rate of tumor necrosis between the 14th and the 28th day(P<0.01).There was no significant difference in the rate of tumor necrosis between the 28th day and the 35th day(P=0.243).The histopathology of paraspinal muscle VX2 tumor showed invasive growth and internal porridge-like necrosis.The tumor cells are diffusely distributed in a strip or nest,and the interstitial blood vessels are abundant.The tumor cells are irregular in shape,large in volume,and have obvious cell atypia and more mitotic figures.On the 35th day,CT enhancement scan of 5 tumor-bearing rabbits revealed retroperitoneal lymph nodes and lung metastasis,and the spinal cord of 2 tumor-bearing rabbits was violated.Conclusion:The paraspinal muscle VX2 tumor has high malignancy,fast growth rate,short tumor formation time and abundant blood supply of tumor tissue.It is an ideal experimental model for studying local treatment of tumor.Part Ⅱ Preliminary study on the effect of microwave ablation of normal muscle on cell proliferation and blood perfusion of distant VX2 implanted tumorObjective:To investigate the effects of microwave ablation(MWA)on the cell proliferation and blood perfusion of distant VX2 implanted tumors.Materials and methods:Sixteen rabbits with paraspinal intramuscular VX2 implanted tumor were randomly divided into MWA group and sham treatment group.In MWA group,ablation of normal muscle tissue simulated complete ablation of tumor.CT perfusion scan of distant VX2 implanted tumor was performed at the points of 24 hours before MWA,immediately after MWA,72 hours,7 days and 14 days after MWA.Peripheral blood samples were collected at the points of 24 hours before MWA,72 hours,7 days and 14 days after MWA,and the concentration of cyclooxygenase-2(COX-2)in rabbit serum was determined by rabbit COX-2 enzyme-linked immunosorbent assay(ELISA).Percutaneous biopsy was performed after simultaneous perfusion scanning.Immunohistochemical CD34 and proliferating cell nuclear antigen(PCNA)staining were performed to count microvascular density(MVD)and PCNA-positive cells.Independent sample t test was used to compare the concentration of COX-2 in peripheral serum,CT perfusion parameters,proportion of PCNA-positive cells and MVD counts of distant VX2 implanted tumor between the two groups.Results:The technical success rate was 93.75%.After MWA,the proliferation of distant VX2 implanted tumor cells was accelerated.compared with sham treatment group,the tumor growth rate(TGR)of distant VX2 implanted tumor in MWA group increased on the 14th day(P≤0.02).The proportion of PCNA-positive cells increased on the 7th and 14th day(P<0.05),and the MVD count increased from the 72nd hour to the 14th day(P<0.05).The CT perfusion parameters of distant VX2 implanted tumor in MWA group were compared with those in sham treatment group:Blood volume(BV)value increased on the 7th and 14th day,and there was significant difference between the two groups(P<0.05),and Blood flow(BF)value decreased at the same time.There was significant difference between the two groups(P<0.01).Mean transmit time(MTT)increased from 72 hours to 14 days,and there was significant difference between the two groups(P<0.05).On the 7th day,permeability surface(PS)increased,and there was significant difference between the two groups(P ≤0.000).Comparison of peripheral serum COX-2 concentration between MWA group and sham treatment group:there was significant difference at 72 hours and 7 days,but there was no statistical difference at 24 hours before MWA and 14 days after MWA.Conclusions:The complete ablation model constructed by MWA of normal muscle tissue is simple and reliable.After ablation,the proliferation of VX2 tumor cells accelerated and the blood perfusion increased.Part Ⅲ Preliminary study on effects of microwave ablation of normal muscle combined with Celecoxib on cell proliferation and blood perfusion of distant VX2 implanted tumorObjective:To preliminarily investigate the effects of microwave ablation(MWA)combined with Celecoxib on blood perfusion and cell proliferation of distant VX2 implanted tumors.Materials and Methods:Twenty-four rabbits were randomly divided into MWA group,combined treatment group and control group(Group A,B and C,8 rabbits each).After MWA normal muscle tissue,the combined treatment group was fed with 50 mg Celecoxib daily,and the other two groups were fed with normal saline.After CT perfusion scanning of VX2 implanted tumors,percutaneous biopsy was performed.Immunohistochemical staining of CD34 and Proliferating Cell Nuclear Antigen(PCNA)was performed to count the ratio of PCNA positive cells and microvascular density(MVD)of VX2 tumor tissue.The concentration of Cyclooxygenase(COX-2)in peripheral serum was measured.Quantitative data were analyzed by independent sample t test or one-way ANOVA.Results:Celecoxib can inhibit the proliferation of tumor cells,reduce MVD and blood perfusion in tumors after MWA.Tumor growth rate(TGR)of the Group B was lower than that of Group A on the 14th day(P=0.022),but there was no significant difference between Group B and C on the 14th day.The PCNA ratio in Group B was significantly lower than that in Group A(P=0.003,0.009),but there was no statistical difference between Group B and C(P=0.428,0.152)on the 7th and 14th day.The MVD count of Group B was lower than that of Group A on the 7th day(P=0.026),and there was no significant difference on the 14th day.CT perfusion parameters present significant differences among the three groups at different time points.On the 7th and 14th day,the BV,MTT and PS values of Group B were lower than those of Group A,while the BF values increased,with statistical differences.On the 7th day,the concentration of COX-2 in peripheral serum of Group B was lower than that of Group A(P=0.022),but there was no significant difference between Group B and group C(P=0.315).On the 14th day.there was no significant difference in the concentration of COX-2 in peripheral serum among the three groups.Conclusion:Combined application of Celecoxib can reduce the blood perfusion and tumor cell proliferation of distant VX2 implanted tumor induced by normal muscle tissue of MWA.