[Effects of 40 Hz multisensory stimulation on trauma-induced anxiety-like behavior in rats].

OBJECTIVE: To investigate the effects of 40 Hz acousto-optical stimulation on anxiety like symptoms of post-traumatic stress disorder (PTSD), with emphasis on the possible molecular mechanism stimulation. METHODS: Thirty SD rats were randomly divided into three groups: Control group, PTSD group and PTSD+40 Hz group,ten rats in each group. The SPS&S model was established in the rats of the PTSD group and PTSD+40 Hz group and, then PTSD+40 Hz group rats were stimulated with 40 Hz acousto-optical stimulation for 7 days. The behavior of anxiety was tested by elevated plus maze (EPM) and open field test (OFT). The expressions of brain-derived neurotrophic factor (BDNF), tyrosine kinase receptor B (TrkB), synapsinⅠand postsynaptic density protein 95 (PSD95) in the rat prefrontal cortex (PFC) and hippocampus (HIP) were detected by Western blot. The mRNA transcription level of BDNF genes in the PFC and HIP was verified by real-time quantitative PCR (RT-PCR) and the distribution of BDNF in the PFC and HIP was determined by immunofluorescence. RESULTS: Compared with the Control group, in the OFT the total distance and the time spending in the center, and in the EPM the total distance were decreased significantly (P＜0.05), the number of entering into the open arm as a percentage of the total number of entering in two arms was decreased,and the expression levels of BDNF, TrkB, PSD95, Synapsin I protein in HIP and PFC, and the mRNA expression level of BDNF were reduced significantly (P＜0.01), the immunofluorescence expression of BDNF was reduced in CA1, DG and PFC in the PTSD group rats; Compared with the PTSD group, the total distance and the time spending in the center in OFT (P＜0.05), the total distance and the number of entering into the open arm as a percentage of the total number were increased significantly (P＜0.05), the protein expression levels of BDNF, TrkB, PSD95, SynapsinⅠin the PFC and HIP, the mRNA expression level of BDNF were increased significantly (P＜0.05), and the immunofluorescence expression of BDNF was increased significantly in CA1, DG and PFC in the PTSD+40 Hz group rats. CONCLUSION: 40 Hz acousto-optical stimulation improves the formation of anxiety-like symptoms in rats with PTSD, which may be related to the synaptic plasticity influenced by BDNF-TrkB signaling pathway.

[Effects of GLAST gene knockout on phenotype and hearing in mice].

OBJECTIVE: To investigate the effects of glutamate aspartate transporter (GLAST)deletion on the normal auditory function of mice. METHODS: We hybridized GLAST+/- mice with C57BL/6J background and identified the genotypes of their offspring by agarose gel electrophoresis. 9-10-week-old mice were selected to detect the expression of GLAST protein in the cochlea by immunofluorescence staining and to verify the knockout results(n=3). The changes in weight from 7 days to 30 days after birth and the 30-day body length of male and female mice were compared(n=8). The auditory brainstem response(ABR) was used to detect the auditory threshold and the amplitude of wave I in 9-10-week-old male and female mice(n=5). RESULTS: Male GLAST-/- mice had shown significantly lower weight and body length compared to male GLAST+/+ and GLAST+/- mice(P＜0.01), and male GLAST-/- mice showed significant differences compared to GLAST+/+ from P7 to P30 statistical time. Male GLAST-/- mice exhibited a significant reduction in weight after P15 compared to male GLAST+/- mice. In contrast, no significant differences in weight and body length were observed in female GLAST-/- mice compared with female GLAST+/+ and GLAST+/- mice. There was no difference in the hearing threshold detected by ABR between the three genotypes in both male and female mice, but the amplitude of wave I in GLAST-/- mice was significantly lower than that in male GLAST+/+ mice(P＜0.01). In contrast, the amplitude of wave I in females was reduced throughout the stimulus intensity but was most significant only at high-intensity stimulation (e.g.80 dB, 90 dB) (P＜0.05). CONCLUSION: GLAST knockout affects the normal growth and development of male mice, and decreases the amplitude of wave I, but do not change the threshold, suggesting that GLAST knockout may lead to synaptic pathological changes, and there are gender differences in this effect.