Objective To observe the damaging effect of microwave on neurons and the protective effect of selenium on damaged neurons after exposure to microwave. Methods In vitro cultured PC12 cells were exposed to 65 mW/cm 2 microwave. The survival rate, SOD activity, GSH-Px activity, and MDA concentration of PC12 cells were detected. The effects of selenium on PC12 cells after exposure to microwave were reflected by these markers. Results Survival rate, activity of superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity of PC12 cells decreased, but malondialdehyde (MDA) concentration of PC12 cells increased after microwave radiation. These changes weakened when PC12 cells were exposed to microwave after pretreatment with selenium. This effect was more significant after pretreatment with selenium at the high dose. Conclusion PC12 cells can be damaged by microwave through peroxidation. Selenium pretreatment can promote the antioxidation and protect PC12 cells from damages induced by microwave.

Objective To compare the analgesic effect ofHuamoyan Keli(HMYKL) between Kunming mice and BALB/c mice.Methods Eighty Kunming mice and eighty BALB/c mice were randomly divided into five groups, respectively: a control group, a ibuprofen group, a HMYKL high-dose group(13.98 g crude dru g/kg), HMYKL middle-dose group(6.99 g crude drug/kg)and a HMYKL low-dose group(3.50 g crude dru g/kg). There were 16 mice in each group with 8 male mice and 8 female mice. Drugs were administered intragastrically daily for 5 days. After 1 h of drug treatment on day 4, the latency of tail-flick response was evaluated using illuminated pain measurement instrument. After the last drug treatment, pain model was established by i.p. acetic acid, writhing latency and writhing times were recorded to evaluate the analgesic effect of HMYKL.Results In tail-flick test, there was no statistical difference among male and female Kunming mice in the HMYKL groups. Among male BALB/c mice, the latency in HMYKL middle-dose group was significantly longer than that in the control group(4.84±1.16 minvs. 3.93±0.76 min,P<0.05). In writhing test, compared with control group(19.06±6.34), the writhing times among BALB/c mice were decreased in HMYKL high-dose group(8.56±6.19), HMYKL middle-dose group(5.73±3.17), HMYKL low-dose group(6.88±4.59)(allP<0.01).Conclusion All dose groups of HMYKL showed good analgesic effect on the pain induced by chemical stimulation and there was no sex difference. Kunming mice were not suitable for the evaluation of the analgesic pharmacodynamics because of their large individual difference. On contrast, BALB/c mice which had less individual difference could be used to produce the model of pain.