Lhrha-Targeted Microbubbles With Ultrasound Irradiation Enhance The Inhibition And Apoptosis Induction Of Cisplatin On Xenografted Ovarian Carcinoma

Objective: To establish nude mouse models of intraperitoneal xenografts with human ovarian carcinoma cells A2780/DDP in order to provide appropriate animal models of human ovarian carcinoma for further experimental study.Methods: Ten nude mice were inoculated intraperitoneally with A2780/DDP cells. Their body weight and abdominal perimeter were measured regularly, and tumor formations in their abdomen were observed. When tumor formations could be touched at the abdomen of all the tumor-bearing mice, four mice were sacrificed randomly and dissected to explore tumors, and histopathologic characteristics of transplanted tumor were studied by light microscopy. The survival time of the other six tumor-bearing mice was recorded, and the transplanted tumor growth was described.Results: The rate of intraperitoneal xenograft tumor formation in nude mice was 100%. The latent period of tumor growth was 12～15 d, and the survival time was 35～40 d. Histopathologic results showed the characteristics of transplanted tumor were identical with those of human serous ovarian carcinoma.Conclusion: Intraperitoneal xenografts models of human ovarian carcinoma in nude mice had been established successfully. The transplanted tumor remained the biological characteristics of original human ovarian carcinoma. The model may be an ideal animal model for the research of human ovarian carcinoma. Objective: To approach whether LHRHa-targeted microbubbles with ultrasound irradiation could enhance the inhibition and apoptosis induction of cisplatin(DDP) on human ovarian carcinoma transplanted intraperitoneal- ly in nude mice.Methods: The nude mouse models of intraperitoneal xenografts were established with human ovarian carcinoma cells A2780/DDP (DDP-resistant, LHRH receptor positive). Thirty tumor-bearing mice were randomly divided into six groups: groupⅠ(DDP+targeted microbubbles +ultrasound), groupⅡ(DDP+common microbubbles+ultrasound), groupⅢ(DDP), groupⅣ(targeted microbubbles+ultrasound), groupⅤ(targeted microbubbles) and the control group(normal saline). GroupⅠ～Ⅴwere experimental groups. After the last treatment, all mice were sacrificed, and their tumors were immediately excised, counted and weighed. The tumor inhibition rate was calculated by mass. The histopathologic characteristics of tumors and main organs were studied by light microscopy. The morphologic alterations in apoptotic tumor cells were inspected under transmission electron microscope. Expressions of matrix metalloproteinase-9(MMP-9) and caspase-3 in tumor tissues were detected by immunohistochemical staining with Streptavidin/Peroxidase (SP) method. The apoptotic tumor cells were detected in situ with terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) technology, and the apoptotic index(AI) was calculated. The content of cisplatin in tumor tissues was determined by reversed-phase high-performance liquid chromatography (RP-HPLC).Results: The tumor number, mass, AI, MMP-9 and caspase-3 expression all varied among the groups(P<0.01). In the groupⅠ, the tumor inhibition rate was highest, and the apoptosis of tumor cells was most obvious, its tumor number, mass and MMP-9 expression were all significantly lower than the other four experimental groups(P<0.05) and the control group(P<0.01), while its AI and caspase-3 expression were both significantly higher than the other groups(P<0.01). The cisplatin content in tumor tissues of groupⅠwas highest, compared with it in the groupsⅡandⅢrespectively, there were significant differences between them(P<0.05, P<0.01).Conclusion: LHRHa-targeted microbubbles with ultrasound irradiati- on can significantly enhance the inhibition and apoptosis induction of DDP on xenografted ovarian carcinoma. Its main mechanism may be increasing intracellular accumulation of cisplatin through enhancing permeability of tumor cell membrane.