| In this paper, we investigated the biological effects of primary cultured hippocampus neuron cells in vitro and hippocampus tissue in vivo, which irradiated by pulse microwave. We firstly adopted local, investigation area pulse field dose instead of space-field dose to indicate irradiation condition. Then, we systematically investigated biological effects from two levels, rat hippocampus tissue in vivo and hippocampus neuron cells in vitro, to obtain the dose-effect relationship and the threshold value of the pulse field intensity, which resulted in obvious biological effects.We investigated the dose-effect relationship between microwave pulse number and the biological effects upon hippocampus cells and tissue under the irradiation of2.71GHz pulse microwave. Besides, we investigated the dose-effect relationship between microwave pulse field intensity and the biological effects upon hippocampus cells and tissue under the irradiation of9.33GHz pulse microwave. We used flow cytometry and UV-Spectrophotometry to study biological effects of hippocampus neuron cells caused by pulse microwave irradiation. We also made rat brain paraffin slice after irradiation and observed the rat hippocampus tissue changes by optical microscopy.The results showed that with the increase of pulse number or field intensity, the biological effects of hippocampus tissue in vivo and hippocampus neuron cells in vitro had the trend of increase, including the release of lactate dehydrogenase, the increase of cells apoptosis and necrosis rate, the decrease of cells survive rate, the increase of hippocampus tissue pathology damage, and the decrease of neural cells density. After2.17GHz of pulse microwave irradiation, obvious biological effects of the tissue and cells appeared with the pulse number of20.The minimum value of the pulse field intensity which aroused obvious biological effects was found, for hippocampus neuron cells in vitro and hippocampus tissue in vivo. Obvious biological effects appeared when pulse field intensity is higher than it. Both of the minimum value of the pulse field intensity for hippocampus cells in vitro and hippocampus tissue in vivo has no significant difference. Conclusion:there is a minimum value of pulse field intensity (between8320V/m and9860V/m)which aroused obvious biological effects for hippocampus, either hippocampus cells biological effects or hippocampus tissue biological effects, obvious biological effects appeared when pulse field intensity is higher than it. The results supply important reference value for research on safe threshold of pulse microwave. |
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