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.
目的: 观察谷氨酸天冬氨酸转运蛋白(GLAST)缺失对小鼠正常听觉功能的影响。方法: 我们选用C57BL / 6J背景的GLAST+/-小鼠进行杂交,用琼脂糖凝胶电泳进行后代小鼠基因型鉴定。我们选用9～10周龄雄性小鼠,用免疫荧光染色技术检测耳蜗中GLAST蛋白表达,对敲除结果进行验证(n=3)。比较雌雄小鼠出生后7d至30 d体重变化及30 d的体长(n=8)。听性脑干反应(ABR)测试9-10周龄雌性和雄性小鼠听觉阈值及其Ⅰ波振幅的变化(n=5)。结果: 雄性GLAST-/-小鼠与雄性GLAST+/+和GLAST+/-小鼠相比,体重及体长均显著降低(P＜ 0.01),其中雄性GLAST-/-小鼠与GLAST+/+相比,在P7至P30统计时间里,均表现出明显差异;与雄性GLAST+/-小鼠相比,P15后均表现出体重显著性降低。而雌性GLAST-/-小鼠与雌性GLAST+/+和GLAST+/-小鼠相比,体重及体长均未见明显差异。雄性和雌性小鼠三种基因型之间ABR检测到听力阈值变化均无差异,但与雄性GLAST+/+小鼠相比雄性GLAST-/-小鼠Ⅰ波振幅明显降低(P＜0.01);而雌性的I波振幅在整个刺激强度都有降低,但是多只在高强度刺激(如80 dB、90 dB)时具有显著性(P＜0.05)。结论: GLAST敲除影响雄性小鼠正常生长发育,同时降低ABR I波振幅,但不改变阈值,这提示GLAST敲除可能导致突触病变,且这种影响存在性别差异。.
Keywords: auditory function; gene identification; gene knockout; glutamate; glutamate-aspartate transporter; mice.