[Establishment of a multiple myeloma local tumor model in mice]

This study was purposed to establish a multiple myeloma local tumor model in the BLAB/c mice. Healthy BLAB/c mice were injected subcutaneously with 6 x 10(5) MPC-11 cells. In the peak time of the subcutaneous nodules observed, five mice were randomized selected to be executed and the subcutaneous nodules of these mice executed were used to detect the CD138 and kappa light chain by means of HE staining and the immunohistochemistry methods. The serum immunofixation electrophoresis (IFE) of tumor-bearing mice were performed at 5, 7, 9, 11, 12, 35 and 65 days after the initial MPC-11 cell injection. Hemoglobin level was assayed at 15 and 30 days after the initial MPC-11 cell injection. The serum levels of IL-6 were also assayed at 35 and 65 days after the initial MPC-11 cell injection. The tumor volume was monitored twice a week and their body weights were measured once a week. The results showed that the peak of the subcutaneous nodules appeared at 12 to 15 days after the initial MPC-11 cell injection. The serum monoclonal immunoglobulin could be detected at 12 days after MPC-11 cell injection. The results of HE staining and immuno-histochemistry assay for detection of CD138 and kappa light chain positive expressions proved that the subcutaneous tumor nodules originated from MPC-11 plasmacytes. The serum monoclonal protein (M protein) of the tumor-bearing mice was detected at 12 days after bearing tumor which manifested thick bands of IgG and kappa light chain. The peak time of mortality was at 20 to 40 days after the initial MPC-11 cell injection, and the median survival time was 31 days. Anemia in mice appeared at 15 days. There was a significant difference of Hb level between the tumor-bearing group and the normal group at 15 and 30 days respectively (p < 0.05). The serum level of IL-6 in tumor-bearing mice was higher than that in the normal group. It is concluded that to establish the multiple myeloma local tumor model in mice by using subcutaneous injection of MPC-11 cells has various advantages, such as simple method of model established, relative high success of bearing tumor, easy observation of tumor growth change and so on. This model can be useful for studying and evaluating the therapeutic efficacy for multiple myeloma through monitoring the changes of tumor size, serum IL-6 level and serum immunofixation electrophoresis.