| Objective:The subcutaneous and claw pad transplanted tumor models of nasopharyngeal carcinoma?NPC?in nude mice were established and the expression of ELAM-1 in tumor-bearing nude mice was detected.To observe and compare the difference of PET/CT molecular imaging scanning after tail vein injection of 18F-FDG between metastasis group and non-metastasis group,and to study and analyze the correlation between SUVmax and T/NT value and ELAM-1 in tumor-bearing nude mice.Methods:?1?Nasopharyngeal carcinoma 5-8F cell suspension was injected into the left hindlimb and claw pad of nude mice,respectively.The status and tumor formation of nude mice were observed,and the body weight of nude mice and the length and short diameter of transplanted tumors were measured.?2?at the 8th week after modeling,18F-FDG PET/CT imaging was performed 1 h after intravenous injection of 18F-FDG 11MBq?300?ci?.The image quality was observed and evaluated by two senior nuclear medicine physicians.The SUVmax of tumor and contralateral muscle were measured by ROI and the ratio of T/NT was calculated.The relationship between the ratio of SUVmax and T/NT and the volume of transplanted tumor and the expression of ELAM-1 protein was analyzed.?3?the nude mice were killed and pathological examination was performed.The morphology and lymph node metastasis of 10 subcutaneous and 16 claw pad models were observed by hematoxylin-eosin staining.According to the results of HE staining,16 nude mice with claw pad model were divided into metastasis group and non-metastasis group.The expression of ELAM-1 protein in the transplanted tumor tissues of the two groups was detected by immunohistochemical?SP?and quantitatively analyzed by Image J software.The independent sample t test was used to analyze the relationship between the metastasis group and the non-metastasis group,and the correlation analysis was used to study the relationship between the two variables?P<0.05,the difference was statistically significant?.Results:?1?the tumor formation rate of 10 subcutaneous and 16 claw pad bearing nude mice was 100.0%,of which only one nude mouse had lymph node metastasis,the other 9 nude mice had no metastasis,the metastasis rate was10.0%.In the claw pad model,9 nude mice had lymph node metastasis,the other 7 nude mice had no metastasis,and the metastasis rate was 56.3%.Before modeling,there was no significant difference in initial body weight between the two groups[?18.50±1.39?g vs?18.56±1.77?g,t 0.072,P=0.943?0.005].?2?the growth curve of nude mice bearing claw pad tumor was drawn.The latent period of 16 nude mice was about 7 to 14 days.4 to 7 weeks after modeling,the tumor volume of nude mice increased exponentially.The tumor volume of nude mice in non-metastasis group was smaller than that in metastasis group[?1216.07±365.73?mm3 vs?1310.84±635.63?mm3,t=0.350,P=0.731?0.005].?3?Immunohistochemical results showed that the expression of ELAM-1was positive in the transplanted tumor and lymph node metastasis of nasopharyngeal carcinoma in nude mice,and the expression was mainly in the cell membrane.The average optical density?MOD?of the transplanted tumor in the metastasis group was significantly higher than that in the non-metastasis group?0.3440±0.1390 vs 0.0550±0.0063,t<6.230,P<0.050?.The difference was statistically significant.?4?the average SUVmax of 18F-FDG PET/CT imaging was 3.42±1.71,and the average T/NT ratio was 4.36±3.72.There was no significant correlation between SUVmax and the volume of transplanted tumor in nude mice?r=0.212,P<0.057?.There was a significant correlation between the ratio of T/NT and the volume of transplanted tumor in nude mice?r=0.549,P<0.050?0.05?.?5?the average SUVmax of 18F-FDG PET/CT imaging metastasis group and non-metastasis group was 3.04±1.16vs2.67±0.69,0.747,P<0.05.the average T/NT ratio between metastasis group and non-metastasis group was3.17±1.49vs2.89±0.66,t=0.515,p0.616?0.05.the mean T/NT ratio between metastasis group and non-metastasis group was 3.04±0.69,0.747,0.467?0.05.the mean T/NT ratio between metastasis group and non-metastasis group was3.17±0.66,t=0.515,p0.616?0.005).There was no significant correlation between SUVmax and the volume of transplanted tumor in nude mice?r=0.207,P=0.441?0.005?,but there was a significant correlation between the ratio of T/NT and the volume of transplanted tumor in nude mice?r=0.185,P=0.493?.There was no significant correlation between SUVmax and ELAM-1 expression in nude mice?r=0.150,P>0.05?,and there was no significant correlation between T/NT ratio and ELAM-1 expression in nude mice?r=0.062,P>0.05?.Conclusion:?1?in this study,the subcutaneous and claw pad transplanted tumor model of nasopharyngeal carcinoma in nude mice with good stability and high tumor formation rate was successfully established,in which the metastasis rate of claw pad model was high?9/16?,and there was no metastasis in subcutaneous model?1/10?.?2?the expression of ELAM-1 in nude mice was high and the expression in metastasis group was higher than that in non-metastasis group,which further indicated that ELAM-1 may play a role in promoting the growth and metastasis of nasopharyngeal carcinoma in nude mice.?3?Clinical PET/CT can well show the metabolism of tumor transplantation in nude mice,subcutaneous and claw pad transplantation tumor uptake,image quality can meet the needs of diagnosis.There was a significant correlation between the ratio of T/NT and the volume of transplanted tumor in nude mice,but there was no significant correlation between SUVmax and the volume of transplanted tumor in nude mice.There was no significant difference in the ratio of SUVmax and T/NT between the metastasis group and the non-metastasis group,and there was no significant correlation between the ratio of SUVmax and T/NT and the volume of tumor and the expression of ELAM-1in nude mice,indicating that the ratio of SUVmax and T/NT could not effectively evaluate the prognosis of nasopharyngeal carcinoma metastasis. |
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