| Objective:To clarify the inhibitory effect of topical administration of Chinese cobra venom toxin(MT-12)on bladder tumor growth,and to verify the possible mechanism and safety of MT-12 inhibiting the growth of transplanted tumor in animal experiments,and further evaluate the application of MT-12.Clinical prospects for the prevention and treatment of bladder cancer.method:The nude mouse(Balb/c)subcutaneous xenograft model was established by using the bladder cancer cell line RT4.According to the dose of MT-12,24 nude mice were randomly divided into high dose group(0.5 mg/kg)and medium dose group.(0.25 mg/kg),low dose group(0.1 mg/kg)and tumor-bearing control group(0.9%NS),6 nude mice per group.The experimental group was injected subcutaneously with MT-12 at different doses per day,once every other day,and a total of 10 injections were required.The control mice were injected with the same amount of normal saline under the peri-tumor.The general condition of the nude mice in each group was observed,and the survival rate and safety of each group were compared.Tumor size was measured every 3 days,the growth curve of subcutaneous xenografts was calculated,the mean tumor weight and the average tumor weight inhibition rate were calculated.All animals were killed the next day after withdrawal.and the transplanted tumors were removed.Gross observation and histopathological examination were performed to evaluate MT-12 inhibition of subcutaneous xenografts in nude mice.The expression of VEGF,ICAM-1 and VCAM-1 in tumor tissues was detected by real-time PCR,and the results were confirmed by immunohistochemistry.To explore the mechanism of MT-12 inhibition of tumor formation in bladder cancer nude mice.result:1.The volume of xenografts in nude mice was larger than that in the MT-12 group.The difference was statistically significant.The volume of xenografts in the three groups of MT-12 patients was statistically different.The control group and the MT-12 group were used.The difference in tumor weight was statistically significant.The tumor inhibition rate was concentration-dependent.The higher the MT-12 concentration,the more obvious the tumor inhibition rate.The difference in tumor weight between the three different MT-12 concentrations was statistically significant(P<0.01).2.The results of HE staining showed that the control group had larger deep staining,nuclear abnormality and nuclear ratio than the tumor cells.The tumor cells in the MT-12 group were less affected than the control group and had certain degenerative changes.3.The results of immunohistochemistry showed that there were significant differences in the expression of VEGF,ICAM-1 and Cleaved casebase-3 in the tumor tissues at the protein level,and the difference was statistically significant.The expression of VCAM-1 was not significantly different in each group.4.Realtime PCR results showed that at the mRNA level,the expression of VEGF,ICAM-1 and Cleaved casebase-3 in each group of tumor tissues was significantly different,and it was concentration-dependent in a certain concentration range.The expression of VCAM-1 was not significantly different in each group.conclusion:1.MT-12 can inhibit the growth of subcutaneous implanted tumors in nude mice of RT4 cells,and it is concentration-dependent in a certain concentration range.2.The nude mice in the treatment group had no obvious adverse reactions.After the tumor formation in nude mice,the body weight of the MT-12 group was lower than that of the control group,and the final body weight was also larger than that of the control group.The difference was statistically significant(P<0.01),indicating that it was effective.At the inhibitory concentration,MT-12 has higher safety.3.MT-12 inhibits tumor growth by inducing apoptosis of tumor cells.4.MT-12 inhibits the production of blood vessels in tumors and the adhesion and invasion of tumor cells by inhibiting the expression of VEGF and ICAM-1 at mRNA and protein levels. |
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