Figure 5B shows a low level of JAK1 phosphoryla tion that occurred immediately at 1 h after EMF expo sure, JAK1 phosphorylation subsequently returned to basal levels. In contrast, phosphorylation of JAK2 was found to increase over a period of several hours, show ing kinetics similar to those of STAT3 table 5 phosphorylation. JAK2 phosphorylation was also apparent at low levels in the control group. The total amount of JAK1 and JAK2 did not change in response to EMF stimulation. Inhibitory effect of P6 on EMF induced CD11b, TNF a and iNOS expression and NO release To further assess the potential role of the JAK2 STAT3 pathway in EMF induced activation and pro inflamma tory responses of N9 microglia, we examined whether the JAK inhibitor P6 could affect EMF induced increase of TNF a, iNOS and NO, and the initial activation of microglia.
Western blot analysis and EMSA experiments show that P6 preconditioning completely blocks activa tion of JAK2 and STAT3 at 3 and 12 h after EMF expo sure. Our results also show that P6 preconditioning Inhibitors,Modulators,Libraries reduces CD11b expression, decreases expression of iNOS and TNF a, and blocks NO release at 12 h after EMF exposure. Interestingly, the fluorescence intensity of CD11b was found to still be significantly increased at 3 h after EMF exposure even with P6 preconditioning. Inhibitors,Modulators,Libraries In addition, P6 preconditioning was found to have a slight inhibitory effect on TNF a and iNOS mRNA expression or protein synthesis at 3 h after EMF expo sure. Discussion In the present study, we observed N9 microglial activation and pro inflammatory responses after EMF exposure.
We found that the JAK2 STAT3 pathway is activated in EMF stimulated N9 microglial cells. The activation of microglia and the secretion Inhibitors,Modulators,Libraries of pro inflammatory factors were signifi cantly reduced by P6 treatment at 12 h after EMF expo sure, while P6 preconditioning did not inhibit the above processes at 3 h post exposure. Our data suggest that the JAK2 STAT3 pathway may play a pivotal role in the pro inflammatory response but not in the initial activation of microglia after EMF exposure. It has been reported that increased CD11b expression corresponds to extent of microglial activation. Here, we observed a dramatic increase in CD11b expres sion in an in vitro model exposing N9 cells to 2. 45 GHz using a waveguide system that simulates occupational or residential exposure, at a specific absorption rate of 6 W kg.
This result suggests that EMF Inhibitors,Modulators,Libraries may poten tially affect microglial activation. Our data are consistent with earlier findings demonstrating increased glial reac tivity in a model using about 900 MHz from a global system for mobile communication, at a high SAR of 6 W kg. Other investigators, however, Inhibitors,Modulators,Libraries have argued that EMF exposure does not lead to microglial activation at this low SAR values simulating either micro wave radiation or mobile telephone radiofrequency fields.