Ultrasound Activation Of Ppix H22 Tumor Cell Apoptosis Induced By

Cancer is one of the most deadly diseases for human beings just bellow the cardiovascular diseases.There are many traditional modalities being used for cancer therapy including radiotherapy, chemotherapy,surgical therapy and so on,but which all can not cure cancer patient effectively due to the unclear mechanism about tumor occurrence.Acordingly,effective therapeutics was in need.In 1978,Doughtery firstly present PDT,and Japan scholar Yumita firstly reported a new mathed called Sonodynamic therapy(SDT).Ultrasound can penetrate deep within tissue and can be focused in a small region of tumor;it can then chemically activate relatively non-toxic chemicals with minimal undesirable side effects.Because of possessing excellent pertinency,penetration ability and no wound for normal tissues, the therapy has advantages for curing deep cancers,which is taken attention of cancer research experts all over the world.a series of theories have been proposed,such as sono-cavitation,free radicals,lipid peroxidation and so on.However the exact mechanism about SDT is still unknown. The sonosensitizers,the ultrasound exposure parameters,and the type of biological system being irradiated are co-determinant factors for the specific mechanisms of sonosensitization.Basing on the international development and earlier experiment results,this paper has done some work about the National Natural Science Foundation of China(Grant No.39870240 and No. 30270383).The present study was to investigate the ultrasonically induced cell damaging effect in the presence of 20μM protoporphyrinⅨ,at the ultrasound frequency of 1.43 MHz and an intensity of 1 W/cm~2.The present results can be explained as follows:1.Fluorescence of PpⅨwas imaged using laser scanning confocal microscopy over time.Result indicated PpⅨbinds to the mitochondria,and mitochondrial localization of PpⅨwas in a time dependent manner.2.By using the conversion of non-fluorescent 2',7'-dichlorodihydrofluorescin(DCFH) to fluorescent 2',7'-dichlorofluorescein(DCF),we monitored intracellular ROS formation.After SDT,DCF fluorescence increased immediately in Us and Up groups.And the result indicated that ROS originated from mitochondria.3.Cell survivals were assessed by the Trypan blue dye exclusion test after ultrasound treatment in combination with PpⅨ.The cell viability in SDT treated group significantly decreased in comparison with other three groups.4.The changes of ultrastructure on H22 cells were observed by scanning electron microscope after SDT treatments.Under the scanning electron microscope,we found that ultrasound alone had some effects on the surface of H22 cells,but with the same ultrasound intensity,the H22 cells showed significantly damaged in ultrasound combined PpⅨgroup,and the cell damage in ultrasound plus PpⅨgroup was more serious than ultrasound group as time passed.Apoptosis bodies formed in the cell membrane.This suggests that PpⅨmay play a role in induction of cell death due to SDT.5.Double-staining experiments that allow for the simultaneous detection of mitochondria and cytochrome c,Bax and Bid showed the translocation of these proteins.In this paper,we have investigated the ultrasonically induced cytotoxicity effect of PpⅨon H22 cells,and preliminarily explored the biological mechanism about sonodynamic treatment.Our results imply PpⅨhas great potential as a sonosentizer for sonodynamic tumor treatment and provide useful information about the application of SDT.However,the research on the effects of ultrasound activating PpⅨis still in its primary stages,further investigations are needed to enrich and perfect this theory.