| Objective:In order to investigate the effect and the possible underlying mechanism ofmagnesium sulfate(MgSO4) on the proliferation, cell cycle, apoptosis of humanumbilical vein endothelial cells (HUVECs) irradiated by60Co γ ray. and the Effect ofmagnesium sulfate on the progress of cell cycles and apoptotic of U251cells afterirradiation. These results can provide experimental evidence and support for the clinicalapplication of magnesium sulfate.Methods:1、HUVECs under exponential growth phase were used in this experiment, and thecells’ survival rate and cells proliferation were detected by the CCK-8method；and theappropriate concentration of MgSO4was Filtered out. Flow cytomety was used to detectcell cycle distribution and Annexin V/PI double staining detection of the early apoptosisrate.2、The NO concentration and the SOD levels were detected using NO kit and SODkit.And the level of malondialdehyde (MDA) included in HUVEC were test by thethiobarbituric acid (TBA) method.3、Real-time PCR assay was applied to detect the expression of ICAM-1andNF-κB mRNA.4、 At different time points,we collected the human glioma U251cells duringlogarithmic growth phase which pretreated with different concentrations ofmagnesium.And then used the flow cytometry to measure the cells’distribution cycleand apoptosis rate.5、SAS8.0software was used for statistical analysis, the data was shown as mean±standard deviation (x s).And A P-value of less0.05was considered statisticallysignificant. Results:1、The experimental results of CCK-8method showed that the concentration ofMgSO4between1.25mg/mL and6.25mg/mL has non-toxic to HUVEC.And theconcentration of MgSO4at6.25mg/mL had no effect on the proliferation of HUVECsno matter whether irradiated by4Gy γ ray.But when the concentration of MgSO4above6.25mg/mL, there showed a different degrees of inhibited effect on HUVEC no matterwhether irradiated by4Gy γ ray, at the same time,the suppression was both in thedose-dependent and time-dependent.2、The concentration of MgSO4at6.25mg/mL or above could alleviate the cells’G2/M arrest induced by irradiation. Compared with the control group, the apoptosis rateof irradiation group increased in different levels.However compared with the time pointof at24h, the apoptosis rate in of6.25mg/mL and12.5mg/mL MgSO4experimentalgroup tended to restore at48h. It indicated that magnesium can alleviate HUVECapoptosis.3、The HUVECs were exposed to γ ray, then the cells were respectively cultured atdifferent times. The concentration of MDA and NO in cells were significant increasedwhile the activity of SOD was decreased. Compared with control group,MgSO4experimental groups showed statistically difference (p<0.05).6.25mg/mL magnesiumcould enhance intracellular SOD activity, reduce Reduce the level of free radicals.4、Real-time PCR test results showed that, the intracellular ICAM-1mRNA andNF-κB mRNA expression level were increased in varying degrees induced by γ ray,butwere both inhibited on some level by6.25mg/mLMgSO45、MgSO4tended to rise the proportion of U251cells’G2/M arrest cycle induced byradiation, meanwhile,6.25mg/mL,12.5mg/mL magnesium increased the apoptosis rateof U251cells at time points of24h,48h. Compared with the irradiation group, MgSO4experimental groups showed statistically difference(p<0.05).Conclusions：1、The MgSO4had no toxicity on HUVECs when in low concentration, it couldreduce the content of free radicals in irradiated cells. While the high concentration ofMgSO4had an inhibitory effect on the proliferation of HUVECs in time-dependent anddose-dependent.2、MgSO4could ease the cells’ G2/M arrest and apoptosis rate of HUVECs afterexposed to4Gy60Co γ ray, in the meantime, regulated and reduced the cells’ radiosensitivity.3、The mechanisms of MgSO4reduce the radiation sensitivity of HUVEC cellsmay be through inhibition of the expression level of ICAM-1mRNAand NF-κB mRNA4、MgSO4could increase the rate of cells’G2/M arrest cycle and promote the cells’apoptosis rate of U251cells after4Gy60Co γ ray. Thus increased the U251cells’radiosensitivity. |
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