The Research On Telomerase Inhibitors AZT Acting On Rat Models Of Malignant Gliomas

Objective:To promote the Scientization and Standardization on the establishment of rat glioma models(RGMs).Studying on the effect of AZT on the rat glioma cells. To contribute to the research on the effective treatments on gliomas.Methods:1. Making up the C6 stem cells and C6 cell suspension, injecting the suspensions into the Cranium of the rats at the cell mount 5×106 respectively.2. Devide the rats into 4 groups when the tumor outgrow:①control group for C6 cells;②treatment group for C6 cells;③control group for C6 stem cells;④treatment group for C6 stem cells. Everyday, we inject the AZT into the abdominal cavity of the rats in the both treatment group at the doseage of 300mg/kg.Two weeks later, we resect the tumors,weighting the flash tumors, oberserving their configuration, and computing the tumor inhibition rate. We checked the pathological characteristics and expression of the apoptosis-related proteins Bax/Bcl-2 of the tumor tissue by using the HE staining and immunohistochemical method. We observed the ultrastructure of the under the electron microscope and tested the apoptosis and cell cycle of the glioma cells by the means of flow cytometry technic.Results:1. We found tumors in 16 rats of all the 20 in the C6 cells,the tumor formation rate is 80%. Under the same condition, we found 19 rats get the tumors in the total 20 rats in the C6 stem cells group, the tumor formation rate is 95%.2. In the C6 cells models the average weight of tumors in the control group and treatment group was 0.8320±0.1046(g) and 0.5839±0.0376(g)(P＜0.01), In the C6 stem cells models the average weight of tumors in the control group and treatment group was 1.1201±0.1072(g) and 0.8827±0.0281(g)(P＜0.01), and the tumor inhibition rate were respectively 29.8%,21.4%, there were statistical differences during the groups (P＜0.05).3. The histopathological test showed that there were more apoptosis happened in the treatment group than in the control group. Expression of the Bax/Bcl-2 was observed in all the samples. In the treatment group the level of Bcl-2 is fewer than in the control group(P＜0.01).This change was more significant in the C6 cell models than in the C6 stem cells models, and show a difference in statistics (P＜0.05). At the same time the expression of the Bax show no statistics difference in the treatment group and contrl group(P＞0.05).4. The result of the microscope:compare to the control group, we found that many nuclei had become pyknotic, and fragmentation and the Chromatin was agglomerate and leaning toward the brim.5. The FCM method showed that the apoptosis rate had a statistical different between the control groups and treatment groups(P＜0.01). We found the cells proportion of S,G2 period increase with a decreasing of the G1 period, The AP(Apoptosis peak) was found in every treatment groups.Conclusion:1. Under the same conditions, the C6 stem cells were more capable of incubating the tumors.Tumors coming from the C6 cells and the C6 stem cells show little difference in pathology2.AZT can induce the apoptosis of the glioma cells and inhibit its proliferation in vitro in rat. The mechanism of that may related to its action in decreasing the Bcl-2 or increasing the Bax/Bcl-2.3. The tumors formed by the C6 cells were more sensitive to the AZT than the tumors coming from the C6 stem cells.