فهرست مطالب masumeh rezaei

In the bystander effect, non-irradiated cells receive biological signals from adjacent irradiated cells and undergo a variety of alterations, considered recently in non-ionizing irradiation like ultrasound waves. In this study, the bystander effect of therapeutic ultrasound exposure alone and in combination with cisplatin was determined. This study aims to determine the bystander effect caused by ultrasound and cisplatin. This experimental study was conducted on the human melanoma cell line including two groups of target and bystander cells. The target cell group was divided into three sub-groups of ultrasound irradiation alone, cisplatin alone, and ultrasound irradiation in the presence of cisplatin that the culture medium of these three groups of cells was transferred to the bystander cell group using the medium transfer technique. Then, apoptotic bystander cells and the expression of P53 and HO-1 in target and bystander groups were measured. The results of the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and apoptosis assay showed that cell death in target and bystander groups receiving the ultrasound with cisplatin is higher than in the ultrasound without cisplatin. PCR (the polymerase chain reaction) results in the target and bystander groups receiving treatments with increased expression of the P53 gene. Target and bystander groups receiving the ultrasound without cisplatin showed a decrease in HO-1 gene expression, while the ultrasound with cisplatin showed an increase in the HO-1 gene compared to the control group.  Combining ultrasound with ultrasound and without it can transfer bystander signals to the cells that are not directly treated.

Bystander effect is defined as biological responses observed in cells that are not exposed to radiation directly but these radiation effects are induced through messages from irradiated cells. One of the non-invasive methods for cancer treatment is ultrasound waves. The therapeutic efficacy of ultrasound waveslike treatment with ionizing radiation can be altered by the bystander effect, so it is necessary to evaluate the bystander effect after ultrasound exposure. In this study, the effect of ultrasound exposure on the expression of P53 gene in neighboring cells has been investigated.

The cells were divided into three groups: control (without treatment), target (under direct ultrasound exposure) and the bystander (no radiation, only receiving target cells culture media). In the target group, the cells were exposed to the ultrasound and after one hour their culture medium were transferred to the bystander group. Cell viability and the expression of P53 gene by using the MTT assay and Real-time PCR was analyzed.

The percentage of cell survival in the target group was reduced compared to the control group, but in the bystander group, this difference was not significant. The expression of P53 gene in the bystander group was statistically increased compared to the control group.

The bystander effect is induced after ultrasound exposure and it can increase the level of P53 gene expression in bystander cells.