Dewen Wang

Neural Cell Apoptosis Induced by Microwave Exposure Through Mitochondria-dependent Caspase-3 Pathway

To determine whether microwave (MW) radiation induces neural cell apoptosis, differentiated PC12 cells and Wistar rats were exposed to 2.856GHz for 5min and 15min, respectively, at an average power density of 30u2009mW/cm2. JC-1 and TUNEL staining detected significant apoptotic events, such as the loss of mitochondria membrane potential and DNA fragmentation, respectively. Transmission electron microscopy and Hoechst staining were used to observe chromatin ultrastructure and apoptotic body formation. Annexin V-FITC/PI double staining was used to quantify the level of apoptosis. The expressions of Bax, Bcl-2, cytochrome c, cleaved caspase-3 and PARP were examined by immunoblotting or immunocytochemistry. Caspase-3 activity was measured using an enzyme-linked immunosorbent assay. The results showed chromatin condensation and apoptotic body formation in neural cells 6h after microwave exposure. Moreover, the mitochondria membrane potential decreased, DNA fragmentation increased, leading to an increase in the apoptotic cell percentage. Furthermore, the ratio of Bax/Bcl-2, expression of cytochrome c, cleaved caspase-3 and PARP all increased. In conclusion, microwave radiation induced neural cell apoptosis via the classical mitochondria-dependent caspase-3 pathway. This study may provide the experimental basis for further investigation of the mechanism of the neurological effects induced by microwave radiation.

RKIP Regulates Neural Cell Apoptosis Induced by Exposure to Microwave Radiation Partly Through the MEK/ERK/CREB Pathway

In the present study, we investigated whether Raf-1 kinase inhibitory protein (RKIP) is important for neural cell apoptosis induced by microwave exposure and explored the role of MEK/ERK/CREB pathway regulated by RKIP in the apoptosis. Differentiated PC12 cells were exposed to continuous microwave radiation at 2.856xa0GHz for 5xa0min with average power density of 30xa0mW/cm2. RKIP sense and anti-sense recombinant plasmids were constructed and transfected into PC12 cells, respectively. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining and caspase-3 activity assay were used to detect cell apoptosis. The results showed that RKIP was downregulated after microwave exposure while the MEK/ERK/CREB signaling pathway was activated excessively. Moreover, the ratio of Bcl-2/Bax decreased, activity of caspase-3 increased, and thus apoptotic DNA fragmentation increased. RKIP overexpression significantly inhibited the phosphorylation of MEK, ERK, and CREB, while RKIP downregulation had the reverse effect. Furthermore, U0126 was found to antagonize the changes caused by RKIP downregulation after exposure to radiation. In conclusion, RKIP plays an important role in the neural cell apoptosis induced by microwave radiation, and the regulation of cell apoptosis by RKIP is partly through the MEK/ERK/CREB pathway. This suggests that RKIP may act as a key regulator of neuronal damage caused by microwave radiation.

Improvement of spatial memory disorder and hippocampal damage by exposure to electromagnetic fields in an Alzheimer's disease rat model.

Although some epidemiological investigations showed a potential association between long-term exposure of extremely low frequency electromagnetic fields (ELF-EMF) and Alzheimer’s disease (AD), no reasonable mechanism can explain this association, and the related animal experiments are rare. In this study, ELF-EMF exposure (50Hz 400µT 60d) combined with D-galactose intraperitoneal (50mg/kg, q.d., 42d) and Aβ25–35 hippocampal (5μl/unilateral, bilateral, single-dose) injection was implemented to establish a complex rat model. Then the effects of ELF-EMF exposure on AD development was studied by using the Morris water maze, pathological analysis, and comparative proteomics. The results showed that ELF-EMF exposure delayed the weight gain of rats, and partially improved cognitive and clinicopathologic symptoms of AD rats. The differential proteomic analysis results suggest that synaptic transmission, oxidative stress, protein degradation, energy metabolism, Tau aggregation, and inflammation involved in the effects mentioned above. Therefore, our findings indicate that certain conditions of ELF-EMF exposure could delay the development of AD in rats.

Rhabdomyolysis-Induced Acute Kidney Injury Under Hypoxia and Deprivation of Food and Water

Background: To investigate the renal pathophysiologyin rhabdomyolysis-induced acute kidney injury (AKI) in rats under hypoxia and deprivation of food and water (HDFW), thus broadening the knowledge about rhabdomyolysis-induced AKI in massive earthquake. Methods: Male Wistar rats weighing 200-230g were randomized into control, rhabdomyolysis (R), HDFW and rhabdomyolysis in combination with HDFW (R/HDFW) group. Experimental rhabdomyolysis rat model was established through clamping hind limb muscles, HDFW model rats were kept in 10% hypoxic chamber unavailable to food and water. At 1, 3, 5, 7, 9, 11d after treatment, serum creatinine (Scr) level, renal index, renal structural changes and cell apoptosis were analyzed. Results: After R, HDFW, R/HDFW treatment, the animals showed significantly higher Scr levels than the control group. Renal index in R and R/HDFW groups elevated remarkably compared with that in control and HDFW group. The results of histopathology, ultra-structure and apoptosis assay suggested that rhabdomyolysis caused renal tubular injury, HDFW treatment resulted in renal vascular dilation, tissue congestion and tubular cell damage. In addition, more severe renal lesion appeared in R/HDFW. Conclusions: We conclude that the association of experimental rhabdomyolysis with HDFW results in a different functional and histological pattern. The rhabdomyolysis-HDFW combination causes more severe renal injury.

Hepatitis C and B virus infection in Chinese patients with extrahepatic bile duct carcinoma

ObjectiveIn China, the incidence of extrahepatic bile duct carcinoma (EBDC) tends to increase over the past decades. The etiology of the noted increase in EBDC is not identified. Approximately, in a half of the overall Chinese patients with EBDC, the causative factors in the development of EBDC have not been demonstrated. There is a high prevalence of hepatitis C virus (HCV) or hepatitis B virus (HBV) in China, both of which can induce malignant transformation of infected cells and strongly associated with hepatocellular carcinoma (HCC). In this study, EBDC tissues from Chinese patients were examined for the presence of HCV and HBV infection to investigate further the potential causes of EBDC.MethodsHCV NS5 protein and HBsAg were detected by labeled streptavidin biotin (LSAB) method; HCV RNA and HBV DNA were detected by in situ polymerase chain reaction (IS-PCR) in formalin fixed, paraffin embedded specimens from 51 Chinese patients with EBDC. HCV RNA and HBV DNA were detected by IS-PCR in 34 Chinese patients with specimens of benign lesions of hepatobiliary tract (control group).ResultsIn 51 case tissue sections of EBDC, NS5 protein was detected in 14 (27.5%), and HBsAg in 5 (9.8%), HCV RNA in 18 (35.4%) and HBV DNA in 8 (15.9%), respectively, of which HCV and HBV co-infection was detected in 2 (3.9%). In 34 case tissue sections of the control group, HCV RNA was detected in 2 (5.9%), and HBV DNA in 3 (8.8%).ConclusionIn this study using standard histochemical and PCR techniques, HCV and HBV genomes and their encoding proteins were detected in the tissues of EBDC. The data show that there is a higher than expected incidence of HCV and HBV presence in EBDC tissues than would be expected on serologic grounds. The detectable rate of HCV RNA in EBDC tissues was significantly higher than in control group (χ2=9.808,P=0.002). As a result, this study indicates that there is a correlation between the presence of HCV infection and EBDC, and HCV infection has possible etiologic significance in the development of EBDC in China. While HBV DNA was detected in EBDC tissues with the difference in the detectable rate of HBV. DNA being not significance between EBDC tissues and the control group (χ2=0.853,P=0.356). Further research is necessary to determine the presence of a causal relationship between HCV/HBV infection and the development of EBDC.

Microarray Analysis of Altered Gene Expression and the Role of ATF3 in HK-2 Cells Treated with Hemin

Objective: To identify gene expression changes and the role of activating transcription factor 3 (ATF3) in hemin toxicity in renal tubular epithelial cells, then elucidate molecular mechanisms of hemin toxicity on renal tubular epithelial cells. Methods: An oligo array comprising 35,035 genes was used to compare differential gene expression in hemin-treated and non-treated HK-2 cells (human renal proximal tubular epithelial cells), and the role of ATF3 in hemin toxicity was assessed using siRNA technique. Results: A total of 128 mRNAs were at least twofold up-regulated and 101 mRNAs were at least twofold down-regulated after hemin treatment. Expression levels of ATF3, heat shock protein 70, c-fos, and c-jun were remarkably increased. Hemin also suppressed nuclear factor-kappa B inhibitor α, β-2 adrenergic receptor, and interleukin-6 mRNA amounts more than twofold. We further demonstrated the protective role of ATF3 in hemin cytotoxicity. Conclusions: The data suggest that hemin caused multiple changes of gene expression in HK-2 cells, and ATF3 protects against hemin cytotoxicity.

Effects of Power Frequency Magnetic Fields Acute Exposure on Growth and Apoptosis of PC12 Cells

PC12 cells were cultured in vitro,then exposed to 50 Hz and 100 μT extremely low frequency electromagnetic fields for 24 h.The proliferation activity,cell cycle and apoptosis was detected respectively by methyl thiazolyl tetrazolium colorimetry,flow cytometry and acridine orange/ethidium bromide,double label immunofluorescence.It was found that: 1) After exposure,proliferation activity was decreased at 0 h(P0.01),but increased at 8 h(P0.05) and 12 h(P0.01),and there were no significant changes at 4 h.2) After exposure,G0/G1 cells were increased(P0.01) and S cells were decreased(P0.05) at 0 h,G2/M cells were increased(P0.05) at 6 h,G0/G1 cells were decreased(P0.01) and S cells were increased(P0.05) at 12 h,there were no significant changes at 24 h.3) The apoptotic rates were increased significantly at 12 h(P0.05),18 h(P0.01) and 24 h(P0.01) during exposure,and 6 h,12 h,18 h and 24 h after exposure(P0.01).The results indicated that 50 Hz and 100 μT extremely low frequency electromagnetic fields exposure for 24 h can change the proliferation activity and cell cycle of PC12 cells and increase cell apoptosis.

INVESTIGATION ON HEPATITIS C AND B VIRUS INFECTION IN CARCINOMA OF THE EXTRAHEPATIC BILE DUCT IN CHINA

Objective: The incidence of carcinoma of extrahepatic bile duct tends to increase during recent decade in China, but its cause is unclear. This study is to investigate the Hepatitis C virus (HCV) and Hepatitis B virus (HBV) infection in the tissues of carcinoma of extrahepatic bile duct and study their correlation. Methods: HCV RNA and HBV DNA was detected byin situ polymerase chain reaction (IS-PCR) in sections of 51 cases of carcinoma of extrahepatic bile duct and 34 cases of control group. Results: Of 51 carcinoma of extrahepatic bile duct, HCV RNA was detected in 18 (35.4%), HBV DNA in 8 (15.9%). In 34 cases of control group, HCV RNA was detected in 2 (5.9%), and HBV DNA in 3 (8.8%). Conclusion: The prevalence of hepatitis C and B viral infection in the tissues of carcinoma of extrahepatic bile duct was significantly higher than in control group. The findings suggest a correlation between HCV, HBV infection and carcinoma of extrahepatic bile duct, inferring HCV and HBV might be involved in the development of carcinoma of extrahepatic bile duct.