| ObjectivesTo study the effect of single and continuous microwave radiation on theapoptosis of Lewis lung carcinoma transplanted tumor in mice and analyses of theexpression of apoptosis related proteins and VEGF. To observe the differencebetween varied dosages and action-times of microwave radiation.Male6-week-old C57BL/6J mice were chosen.Plant Lewis lung carcinoma cellin the back of the mice. Choose single or continuous microwave radiation for Lewislung carcinoma transplanted tumor in every mouse.Single microwave radiation: Mice were divided into5groups (S1: the controlgroup, S2:10mW*5min, S3:10mW*15min, S4:30mW*5min, S5:30Mw*15min).Separate the tumor after6h or24h of microwave radiation. Pathologic morphologyobservation, calculation of nuclear fission, TUNEL were performed to observe theapoptosis.Immunohistochemistry and image analysis were used to observe theexpression of P53, Bcl-2, Bax, Caspase-3proteins and the expression of VEGF.Continuous microwave radiation: Mice were divided into5groups (C1: thecontrol group, C2:10mW*5min, C3:10mW*15min, C4:30mW*5min, C5:30Mw*15min), once a day for a week. Measure the tumor size the next day. Datasare used to draw the tumor growth curve. Weigh the tumor after microwave radiation.Pathologic morphology observation, calculation of nuclear fission, TUNEL wasperformed to observe the apoptosis. Immunohistochemistry and image analysis wereused to observe the expression of P53, Bcl-2, Bax, Caspase-3proteins and VEGF.Results1. Single microwave radiation:There are no significant difference between experimental groups and controlgroup in pathological morphology observation、the counts of nuclear fission、the apoptosisrate and the expression of P53, Bcl-2, Bax, Caspase-3proteinand VEGF after6h or24h of microwave radiation. 2. Continuous microwave radiation:The weight of tumor is decreased in experimental groups compared with controlgropu,but not significantly different.We observed dispersal and multiple necrotic fociincreased hemorrhage and petechiae around the tumor in H&E sections,especially ingroup C5.The number counts of nuclear fission are significantly decreased inexperimental groups (C1:9.32±1.78%, C2:6.00±2.03%, C3:5.92±0.81%，C4:5.44±1.48%，C5:4.76±1.16%，p＜0.05), which is negatively correlated with thepower density of microwave and radiation time.The apoptosis rate significantly increased in experimental groups(C1:5.53±0.09%, C2:6.40±2.94%, C3:13.20±4.29%, C4:11.00±4.36%，C5:19.42±2.42%), except group C2, which is positively correlated with the powerdensity of microwave and radiation time.The radiation significantly upregulated the expression of P53(C1:3.33±1.31%,C2:5.87±1.89%, C3:7.83±1.15%，C4:6.28±1.26%，C5:12.07±2.15%，p＜0.05),except group C2（p0.05）, which is also positively correlated with the power densityof microwave and radiation time.The expression of Caspase-3is upregulated in radiation groups（C1:3.530.96%, C2:5.521.52%、C3:5.421.17%，C4:5.731.66%，C5:11.803.73%，p＜0.05）, which is positively correlated with the power density ofmicrowave and radiation time.No significant difference was detected in the paired comparisons of C2-C3、C2-C4,whereas in group C5it is significantly higher than group C3and C4.The radiation significantly upregulate the expression of Bax （C1: IOD1.02±0.33，C2: IOD1.26±0.53, C3: IOD2.30±0.72, C4: IOD2.04±0.27, C5: IOD2.45±0.89, groups C3、C4、C5are significantly higher than control group, p＜0.05，except for group C2p0.05），which is also positively correlated with the powerdensity of microwave and radiation time.The expression of Bcl-2is downregulated in radiation groups（C1: IOD3.66±1.00，C2: IOD2.81±0.60, C3: IOD2.69±0.32, C4: IOD2.66±0.76, C5: IOD 1.13±0.02, group C3andC5are significantly lower than control group，p＜0.05，whereas we detected no significant difference in group C2and C4from controlgroup，p>0.05）,which is negatively correlated with the power density of microwaveand radiation time. No significant difference was detected in the paired comparisonsof C2-C3、C2-C4,whereas in group C5it is significantly higher than group C3andC4.The expression of VEGF is upregulated after the radiation （C1: AOD0.18940.0114, IOD2.690.61，C2: AOD0.19330.0288, IOD3.890.79，C3:AOD0.22600.0205, IOD4.200.75，C4: AOD0.20270.0095, IOD4.101.88, C5:AOD0.22200.0198, IOD4.150.33), they are significantly higher in group C3andC5than control, p＜0.05，but not group C2and C4, p0.05).ConclusionsThe single microwave radiation had no effect on tumor tissue when it isperformed in small dose and short term.The continuous microwave radiation can cause the damage of the tumor tissueapoptosis of tumor cells, which may be related with up or downregulation of P53,Bax, Caspase-3,Bcl-2; microwave cause the upregulation of the expression of VEGF,the radiation effect is positively correlated with radiation dose and radiation time.Microwave radiation can promote apoptosis of in Lewis lung carcinoma transplantedtumor in mice. The effect depends on the action time and radiation dose. The P53,Bcl-2, Bax, and Caspase-3protein may be involved in the apoptotic process of inLewis lung carcinoma transplanted tumor in mice. Microwave radiation can changethe expression of VEGF in tumor tissues，the effect of is positively correlated to theaction time and radiation dose. |
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