Klasik ve pulse radyofrekans termokoagülasyonun nöroablatif etkilerinin nöronal dizin hücreleri üzerinde incelenmesi

Neuroablation generated by the high-temperature in conventional RF (CRF) can lead to neuritis-like reactions, motor deficits and deafferentation sequels. The ongoing new searches in order to reduce the side effects resulted in the discovery of pulsed RF (PRF) by Sluijter in 1996. Although formation of heat causing ``thermocoagulation?? of the nervous tissues is thought to be responsible of the clinical outcome, pulsed radiofrequency (PRF) delivers the RF current without producing destructive levels of heat. Pulsed radiofrequency (PRF) has been rapidly accepted for its clinically demonstrated effectiveness and the lack of any permanent neurological deficits. Although the clinical results support the use of PRF, the mechanism of action is still unclear.In this study, the aim is to investigate the effects of RF treatment on the behavior of neuronal cells by using neurotoxicity screening test and apoptosis and oxidative stress immunohistochemistry in neuroblastoma cell line. The relationship between the oxidative stress on the neurons caused by PRF application and subsequent inhibition of neuritis and the level of apoptosis will provide important information in terms of guidance of future uses of these applications.In understanding the effects of RF applications on neurons, three-dimensional in vivo environment becomes available to demonstrate only the significant toxic effects and poses difficulties in understanding the mechanisms used. Therefore, the two-dimensional in-vitro culture environments which are simple and allowing a better understanding of the mechanisms are required by eliminating the complexity of in-vivo environments. These environments are important in terms of investigating the effects of RF applications, especially RF applications, on the neuronal behavior, demonstrating the potential hazards of the application, and examining their mechanisms of actions.In this study, rat neuroblastoma NaB2 cell line was used. 24 cell culture containers were used, and 4 different groups were created based on the duration of the RF. The durations of RF application were 180 seconds, 360 seconds and 540 seconds in the first, second and third groups, respectively. The fourth group was not underwent RF application and considered as a control group. Each of these 4 groups were divided into four sub-groups as CRF at 40°C, PRF at 40°C, CRF at 60°C and PRF at 60ºC. Steroid was applied in one of each cell line of the control group and the first group (180 sec), and the effects of steroids on the lesion were investigated. After RF applications, iNOS, eNOS, and TUNEL staining were performed. Phase contrast microscope images were transferred to a computer, and morphometric analysis was performed.A significant cell loss was observed as a result of the use of RF application for 540 sec at 40°C It was proven that significant cell death occurred with the applications for 360 sec at 40°C, and this was more pronounced with the use of CRF. It was demonstrated that the rate of cellular death was lower by approximately one-third of the culture container, and they generally had a healthy appearance with the applications for 180 sec at 40°C This appearance was found to be more evident in the PRF applications than the CRF applications. It was found that the cells in the 180 sec at 60°C group were affected by a similar level that of 360 sec groups and that this influence was more pronounced in CRF application.The cell death was determined to not constitute a difference between applications; the effect of RF applications for 180 sec at 40°C was seen as the inhibition of neuritis at high magnification. Different levels of neuritis extension occurred in every field, and the toxic effect that occurred after the RF applications was seen to be heterogeneous.When the relationship between the inhibition of neuritis caused by RF applications and oxidative stress, and the presence of apoptosis mechanism brought by this relationship were investigated, the basal level of iNOS and eNOS media were detected and a small amount of apoptotic cell were found in the control samples. There is a marked increase in the presence of the NOS with the increase in RF duration, accompanied by an increase in apoptotic cells. This effect was found to be more pronounced with the CRF application when compared with the PRF application.In morphometric analysis, it was found there is a significant increase in cell death with increasing RF durations (p <0.001), but not in the apoptotic cells. The amount of cell death was lowest with the application for 180 sec at 40°C, and the application at 60°C caused a significant increase in toxic effect (p <0.05), but not in the number of apoptotic cells. While a lesser extent of inhibition of neuritis occurred in PRF applications for 180 sec and 40°C (p <0.05), quite significant level of inhibition of neuritis occurred in CRF application (p <0.001). While similar results were available for iNOS and eNOS, the least apoptotic effect was found to be with the CRF application in TUNEL staining.When compared to the PRF, the toxic effect of CRF was found to cause macro-findings associated with the necrosis characterized by the numerical decline in the cells, and mostly moderate toxic effects with the inhibition of neuritis. The latter effect was also found to be associated with NOS and apoptosis.In conclusion, we concluded that the toxic effect was increased with the increasing duration and temperature in RF applications, a significant damage occurred in CRF applications, and this damage can be lessened but not eliminated with PRF application. Steroid application was found to have no in vitro protective effect.