导向药物转化生长因子α-Sporin对增殖平滑肌细胞生长的抑制作用

为证实生物导向药物对平滑肌细胞增殖的作用，用SPDP化学联结法合成了转化生长因子α-Saporin，通过MTS比色法观察了转化生长因子α-Saporin对培养中的增殖平滑肌细胞的细胞毒性作用，并用氟标胸腺脱氧嘧啶核苷掺入法进一步探讨了转化生长因子α－Saporin对平滑肌细胞的DNA合成的影响以及过量转化生长因子α-对转化生长因子α-Saporin的受体竞争抑制作用。结果发现，联结后的转化生长因子α－Saporin可明显抑制平滑肌细胞的增殖，而Saporin的抑制作用却很弱，转化生长因子α－Saporin对培养的平滑肌细胞氘标胸腺脱氧嘧啶核苷掺入量有明显抑制作用。与对照组比较氘标胸腺脱氧嘧啶苷掺入量降低了39．1％（P＝0．0017），而在加入表皮生长因子受体的配体转化生长因子α后可明显竞争抑制转化生长因子α－Saporin对平滑肌细胞增殖的细胞毒性作用。实验结果提示：转化生长因子α－Saporin通过表皮生长因子受体介导已具有较Saporin明显增强的细胞毒性作用。本实验为转化生长因子α－saporin在经皮腔内冠状动脉成形术术后再狭窄的临床防治中的应用的研究提供初步的实验依据。αα

Cytotoxic Effects of Transforming Growth Factor-

Aim　To testify the inhibitory effects of transforming growth factor-( conjugated with cytotoxin saporin on proliferating vascular smooth muscle cells.　Methods　Conjugation of saporin to TGFα was accomplished after derivatization of saporin and TGFα with N-succinimidyl-3 (2-pyridyldithio) proprionate and final purification of the conjugate was achieved within Eppendorf Centrifugal Filter Tubes.　Biological assay of cytotoxicity was measured by MTS (a colorimetric method).　The studies of influence of TGFα-Saporin on values of Thymidine incorporation into SMCs were measured by 3 H-thymidine uptake and receptor competition studies of TGFα-Saporin are measured by adding excess TGFα in SMCs exposed for TGFα-Saporin.　Results　Biological assay of cytotoxicity assays testified TGFα-Saporin conjugate could inhibit specially proliferation of SMCs in culture.　The absorbances measured by MTS of the group treated by TGFα-Saporin（10-7 mol/L）reduced to 60% comparedwith the control group（P=0.0003).　However, the absorbances of the group treated by saporin (10-3mol/L) only reduced to 40% of the control group.　The values of thymidine of TGFα-Saporin group (10-9 mol/L) in comparison significantly decreased to 60.9% of the control group (P<0.05), suggesting that cellular DNA synthesis obviously decreased as TGFα-Saporin was added.　Saporin did not affect cellular DNA synthesis at 10-3 mol/L.　But excess TGFα(10-7 mol/L) added in SMCs exposed for TGFα-Saporin (10-9 mol/L) can completely blocked the inhibitory effects of TGFα-Saporin so that 3 H-thymidine uptake in the group was similar compared with the blank control group.　Conclusions　TGFα-Saporin possesses the more effective cytotoxicit.