Background: Buthus martensii Karsch Chlorotoxin（BmK CT） has been shown to inhibit the invasion ability of glioma cells by selectively restraining the Cl channel of glioma cells.Purpose: We aim to explore the effect and the mechanism of125I-BmK CT on the invasion ability of glioma.Methods: Transwell method was used to evaluate the invasion ability of glioma cells.The ELISA was used to evaluate the effect of125I-BmK CT on the secretion of MMP2.The Real-Time PCR and Western-blot were used to detect the effect of125I-BmK CT on the expression of MMP2 mRNA and protein.Results: Transwell indicated that both125I-BmK CT and BmK CT can inhibit the invasion ability of glioma cells

and125I-BmK CT was superior to BmK CT（P<0.05）.ELISA indicated that the secretion of MMP2 protein can be inhibited by125I-BmK CT significantly（P<0.05）.Real-Time PCR indicated that125I-BmK CT can not affect the synthesis of MMP2 in gene level（P>0.05）.Western-blot indicated that 125I-BmK CT can inhibit the protein synthesis of MMP2（P<0.05）.Conclusions:125I-BmK CT can inhibit the invasion ability of glioma cells

which may be related with the decreased secretion and synthesis of MMP2.