Expression And Distribution Of Aquaporin 1 In Osteosarcoma And Its Significance

Objective:To study the expression and the distribution of aquaporin1(AQP1) and tumor microvessel density(MVD) in osteosarcoma group and control group,and to detect the correlation between MVD and the expression of AQP1,then try to find out the significance of AQP1 in osteosarcoma.For the role of AQP1 adds new content in angiogenesis and development of osteosarcoma, and provide a new target to antiangiogenesis therapy of osteosarcoma.Method:AQP1 was detected by S-P immunohistochemical method in 39 cases of paraffin-embedded sections of osteosarcoma and 22 cases of paraffin-embedded sections of control group,which includes 11 cases of osteochondroma and 11 cases of osteofibrous dysplasia. The distribution of AQP1 in tissues and the appearance of AQP1 positive cells were observed with high-scope, and the expression of AQP1 was detected by artificial counting and auto-image analysis, to determine if there was difference between the two groups. Tumor microvessel was marked by CD34 antibody by immunohistochemical method, and the different appearances of tumor microvessel were observed with high-scope between two groups , and MVD was counted with high-scope.Applying SPSS11.5 statistical package, carry out two-samples t-test(if necessary t,- test),correlation test uses Pearson linear regression analysis on results.P value less than 0.05 was considered statistically significant.Results:①This immunohistochemical method showed that AQP1 protein was strongly expressed in the endothelium of microvessels and small vessels in all cases; AQP1 protein is mainly localized in the cellular membranes and cytoplasm of the most osteosarcomatous tumor-cells, especially in the osteosarcomatous tumor giant cells, but scattered in the cellular membrane and almost no or weak staining in tumor-cells in control group.②The percentage of AQP1 positive cells (YP) by artificial counting in osteosarcoma (44.08±22.29)% was significantly higher than that in control group (15.27±8.80)% (P<0.01); The positive rate of AQP1 by artif-counting grade in osteosarcoma(79.49%)was significantly higher than control group(27.27%)(P<0.01);The MD of AQP1 by IPP6.0 auto-image analysis in osteosarcoma[(11.06±8.05)×10-3] was also significantly higher than control group[(5.31±2.99)×10-3](P<0.01);All the data indicate that the expression of AQP1 in osteosarcoma was higher than that in control group.③MVD by CD34 staining in osteosarcoma (38.31±17.73) was significantly higher than that in control group(15.14±7.83) (P<0.01).④In osteosarcoma , there is a significant positive correlation between YP of AQP1 and MVD(r=0.341,P<0.05),so the stronger the expression of AQP1,the higher that of the MVD.Conclusion:This study confirmed for the first time that AQP1 was strongly expressed in the endotheliums of microvessels and small vessels in all cases; AQP1 was mainly localized in the cell membranes and cytoplasm of the most osteosarcomatous tumor-cells, especially higher expressed in the osteosarcomatous tumor giant cells; The reason why so many osteosarcomatous tumor-cells strongly expressed AQP1 was unknown ; MVD in osteosarcoma was significantly higher, manifested that the role of AQP1 in osteosarcomatous development and in differentiating the innocuousness or malignancy of bone tumor ; The AQP1 expression in malignant osteosarcoma was remarkably stronger, signifying the role of AQP1 in osteosarcomatous development and metastases, moreover a significant positive correlation between YP and MVD in osteosarcoma , further indicated the important role of AQP1 in tumor angiogenesis. This study revealed that AQP1 may become a new target for osteosarcomatous therapy .