RESUMO
Objective To investigate the impact of ultrasound-targeted microbubble destruction ( UTMD) combined with carboplatin sustained release microspheres on the temperature of the tumor microenvironment and the concentration of the drug release in target tumor . Methods Twenty tumor bearing rabbits were randomly assigned into 4 groups : the control group without any treatment ; the carboplatin-loaded PLGA microspheres (CPMs) group ,only intratumoral injection of carboplatin sustained-release microspheres ;the S2000 group ,diagnostic ultrasound irradiation using S2000 equipment on local chemotherapy tumor tissue combined with lipid microbubbles ;the AP-170 group ,the same treatment as the S2000 group except the application of AP-170 instead of S2000 . Far-infrared thermography was performed to measure the tumor temperature . The experimental equipment of extracorporeal circulation was set up . The experimental conditions were assigned into 4 groups :37℃ CPMs group ,37℃ S2000 group ,37℃ AP-170 group ,40℃ AP-170 group . After irradiation experiment ,the carboplatin absorbance was measured at 229 nm wavelength . The absorbance difference of each group was compared with the 37℃ CPMs group ,and each group was tested 10 times . Results The intratumorous temperature in AP-170 group increased to (40 .24 ± 0 .72) ℃ ,which was significantly different from all the other groups ( P ＜ 0 .01).The in vitro drug release experiment showed that the absorbance in the 40 ℃ AP-170 group was 0 .1537 ± 0 .0094 ,which was significantly different from other groups ( P ＜ 0 .01).Higher temperature promoted the release of chemotherapeutic drugs from carboplatin sustained-release microspheres , thus enhanced the chemotherapeutic effect .This might be the mechanism that UTMD affects the microenvironment in this experiment .Conclusions UTMD increases the permeability of tumor cells .The increase of temperature promotes more drugs into the microenvironment of tumor cells .Thus ,the local chemotherapeutic effect is enhanced in the tumor .