Gao Yabing

Establishment of Imaging Mass Spectrometry for Biological Tissues and Its Application on the Proteome Analysis of Microwave Radiated Rat Hippocampus

Abstract Imaging mass spectrometry based on matrix assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) for biological tissues was established. The key experimental factors were optimized as follows: 20 mg ml −1 of sinapic acid as matrix, ACN:H 2 O (1:1, v/v) as matrix solvent; MALDI-TOF-MS was operated at positive linear scan mode, 30%–50% of laser power range, 200 laser shots per scan, and 200 μm as the laser moving step. This method was used for the proteome analysis of SD-rat brain hippocampus after microwave radiation. 5902 spectra and 320 MS images per slice for normal group were acquired; 5993 spectra and 346 MS images per slice for microwave radiation group were acquired. Software was developed to calculate the Hits values, which reflected the component distribution and abundance. By statistic analysis of normal species and radiation group, a total of 199 differentiate molecules were found, out of which 194 molecules were up regulated. These molecules may be important for investigating the injury mechanism of hippocampus microwave radiation.

Activation of HIF-1α/ERK Pathway Regulates the Injury of Neuron Mitochondria in Hippocampus Induced by Long-term Microwave Exposure

Change of HIF-1α/ERK signaling pathway and its significance in the damage of the hippocampus induced by microwave exposure provides new targets for in-depth study of microwave injury mechanisms and prevention and control measures and approaches. 100 male Wistar rats were exposed to microwave at 2.5, 5 and 10 mW/cm2. The exposure time was 6 min/times, 5 times/week, and the exposure was continuous for one month. Rats were sacrificed at 6 h, 7 d, 14 d, one and two months after exposure. The expression of hif-1α mRNA in hippocampus was detected by real-time PCR. HIF-1α, ERK1/2, p-ERK1/2 expression were detected by Western blot, IHC and image analysis. The mRNA and protein levels of HIF-1α in hippocampus were increased significantly at 14 d and one month in 2.5 and 5 mW/cm2 groups, while decreased from 14 d to two months in 10 mW/cm2 group. There was no significant change of ERK1/2 within two months in exposure groups. In sham group, p-ERK1/2 was expressed weakly positive in neuron cytoplasm of hippocampus, while there was no changes in 2.5 mW/cm2 group, and p-ERK1/2 was expressed positive or strong positive from 7 d to one month in 5 and 10 mW/cm2 group. Therefore, HIF-1α and p-ERK1/2 expression in hippocampus were changed after 2.5, 5 and 10 mW/cm2 microwave exposure, which indicated the activation of HIF-1α and ERK pathway participated in the processes of hippocampus mitochondria injury induced by microwave, and might repair the mitochondria injury.

PI3K Activates NF-κB Signal Pathway Which Prevents IEC-6 Cells from Neutron Irradiation

Neutrons are high LET rays. It damages the bodies more seriously than γ rays. Intestinal epithelial cells are very sensitive to neutron irradiation. While by far, there are no papers concerning PI3K regulation of NF-κB signal pathway and its effects in the intestinal epithelial cells damaged by neutron irradiation. To explore the change of nuclear factor-kappa B (NF-κB) pathway in intestinal epithelial cell No.6 (IEC-6) cell line induced by fission neutron irradiation and the regulation of PI3K, we set up IEC-6 cell lines model by subculturing. Three groups of IEC-6 were given: control group, neutron irradiation group, LY294002 treatment and neutron irradiation group. Except the control group, the other groups were homogeneously irradiated by 4 Gy fission neutrons. The LY294002 treatment group cells were given LY294002 before 24 h of neutron irradiation. At 6 h and 24 h after neutron irradiation of 4 Gy, the proliferation ability of the IEC-6 cells was assayed by MTT colorimetry, the apoptosis and necrosis rates of the IEC-6 cells were assayed by flow cytometry (FCM), and changes of NF-κB (p65), the inhibitor of kappa Bα (IκBα) and IκB kinase β (IKKβ) were assayed by Western blotting. We quantitatively analyzed the results by means of image analysis. At 6 h and 24 h after neutron irradiation of 4 Gy, their proliferation ability decreased and lots of apoptosis and necrosis IEC-6 cells were found; the changes of NF-κB and IKKβ in IEC-6 cells were decreased and that of IκBα increased. The injuries of LY294002 treatment and neutron irradiation group were more serious than the control and neutron irradiation group. We found that IEC-6 cells were obviously damaged and induced serious apoptosis and necrosis by neutron irradiation of 4 Gy. The NF-κB pathway in IEC-6 cells was activated by neutron irradiation which can protect IEC-6 against injury caused by neutron irradiation. PI3K can activate NF-κB pathway which protects IEC-6 cells from being damaged by neutrons.