| Osteosarcoma mainly exists in youngsters, which is the most common malignant tumor of bone, about occupying 20% of bone malignant tumors. In the last twenty years, the treatment of osteosarcoma has been made a great progress. Now ,effective neoadjuvant chemotherapy has been applied, and becomes the standard pattern for osteosarcoma therapy o Cisplatin is one of the most early and active chemotherapy drug for osteosarcoma. But more and severe toxicity has impaired the clinical effect and application of cisplatin. Carboplatin would appear to have a similar qualitative spectrum of activity to cisplatin ,and exhibits a more favorable toxicity profile and a easier administration than cisplatin, so has replaced cisplatin in chemotherapy regimens of some diseases..But myelosuppression, particularly thrombocytopenia is the dose-limiting toxicity for carboplatin. Some investigation has been done on cisplatin combined with carboplatin for some malignant tumor(ovarian cancer and lung cancer).The results have demonstrated that though cisplatin and carboplatin are some category of chemotherapy drug,the toxicity of eath drug is different. Cisplatin combined with carboplatin would not influence the clinical effect but relieve their toxicity. This study want to provide with experimental proofs for cisplatin combined with carboplatin in therapy of osteosarcoma through comparing the cytotoxity of half dose cisplatin combined with half dosecarboplatin , cisplatin and arboplatin in osteosarcoma cell line(OS-732).Materials and MethodsMaterialsOS-732 cell line;Cisplatin; Carboplatin; MTT(Amresco): RPM1 1640medium (Gibcol); DMSO ; newly born bovine serum; 96-well multiplates; cell culture incubator(Heraeus,HERA cell); invert microscope(Leica,MPS 30); Elisa reader (Opsys MR)MethodsHuman osteosarcoma cell line (OS-732) was cultured with RPMI-1640 medium containing 10% (vol/vol) heat-inactivated newly born bovine serum ,100 units/ml penicillin, and 100 ug/ml streptomycin at 37癈 in a CO2 incubator in 95% air:5% CO2, at 100% humidity. A solution of 0.25% trypsin was used to detach OS-732 cells for subculture.OS-732 cells were diluted with medium to 1 X 105 cells/ml and aliquots (1.8 x 104cells/180 ul) were placed in individual wells in 96-well multiplates. Each well in addition received 20 ul of either cisplatin or carboplatin. All six wells in the same column had an identical concentration of cisplatin, ranging from 1.0 to 100.0 ug/ml, or carboplatin ranging from 40.0 to 320.0ug/ml. Cells were incubated for 48hrs, then their viability was determined by the colorimetric MTT assay . according to the mean 1C50 of cisplatin and carboplatin for OS-732 cell line we have gotten, we set two group. Group A: all six wells in the same column had ICso of cisplatin , IC5o of carboplatin ,orl/2 IC50 of cisplatin combined with 1/2 IC50 carboplatin, Cells were incubated for 48hrs; Group B: all sixwells in the same column had IC50 of cisplatin , IC50 of carboplatin ,orl/2 IC50 ofcisplatin combined with 1/2 IC50 carboplatin, Cells were incubated for 72hrs . then their viability was determined by the colorimetric MTT assay .The MTT solution (5 mg/ml in PBS, 20 ul) was added to each well and the plates were incubated for 4 hrs. The bulk of the medium from each well was suctioned off, leaving 10-20 ul behind, together with purple formazan crystals. DMSO (150.0 ul) was added to each well to dissolve the crystals and the plates were shaken for 10 minson a shaker. The absorbance (^)of each well was read at 570nm on a Opsys MR Elisa reader. Calculation Cytotoxicity Index (CD, CI= (control groups-testing group S) / control group A xlOO%. We treat the results with method of Post Hoc Tests in SPSS9.0 statistics software.Results.l.The mean absorbance (A) and CI of OS-732 cells incubated with cisplatin for 48hrs, see table 1:2.The mean absorbance (A) and CI of OS-732 cells incubated with carboplatin for 48hrs. see table 2:the mean IC5o of carboplatin for OS-732 cells is 200.0u.g/ml.3.The mean a... |
