CBA小鼠内耳感觉上皮的参考数据

Reference data of sensory epithelium in the inner ear in CBA mice

目的测量成年CBA小鼠耳蜗和前庭的有关数据,为内耳感受器定量分析提供参考依据。方法将6只出生后3个月左右的成年CBA小鼠(12耳)的耳蜗和前庭各终器取出并制备成全耳蜗基底膜铺片和全前庭终器铺片。测量全耳蜗基底膜的总长度,以及基底膜和Corti器在耳蜗不同部位的宽度。观察并记录全耳蜗毛细胞的总数和基底膜上不同区间的毛细胞密度。观察并记录椭圆囊斑和球囊斑毛细胞的总数及其微纹区和周边区的毛细胞密度,记录壶腹嵴上的毛细胞密度。结果正常成年CBA小鼠的耳蜗基底膜长度为(5.76±0.196)毫米(平均数±标准差,下同),基底膜的宽度在耳蜗底部距起始端约1.5毫米处为(339.1±9.87)微米,在耳蜗中部距起始端约3毫米处为(304.5±11.82)微米,在耳蜗顶部距起始端约5毫米处为(300.1±7.22)微米,说明小鼠耳蜗基底膜的宽度从底回到顶回逐渐变窄。Corti器的宽度在耳蜗底部距起始端1.5毫米处为(37.80±2.24)微米,在耳蜗中部距起始端约3毫米处为(45.00±2.67)微米,在耳蜗顶部距起始端约5毫米处为(52.20±3.16)微米,可见Corti器的宽度从底回到顶回逐渐变宽。CBA小鼠全耳蜗毛细胞的总数为(3116.41±151.91)个,其中内毛细胞总数为(680.67±17.50)个,而外毛细胞的总数是(2435.8±143.46)个。耳蜗内、外毛细胞的平均密度为(541.1±9.36)个/毫米,其中内毛细胞的平均密度为(118.3±2.68)个/毫米,外毛细胞的平均密度为(422.8±11.87)个/毫米,耳蜗毛细胞在耳蜗基底膜上不同区间的毛细胞密度无明显差异(P>0.05)。小鼠椭圆囊斑上的毛细胞总数为(3300±177.51)个,球囊斑上的毛细胞总数为(3045±361.57)个。前庭球囊斑和椭圆囊斑微纹区和周边区的毛细胞密度基本相同(P>0.05),两个囊斑微纹区的平均毛细胞密度为(40.2±6.59)个/0.0025mm2,两个囊斑周边区的平均毛细胞密度为(53.2±7.18)个/0.0025mm2,可见囊斑微纹区的毛细胞密度低于周边区。尽管小鼠上半规管和后半规管壶腹嵴的毛细胞区被位于嵴中央的上皮细胞分隔为两个区域,但三个壶腹嵴上的毛细胞密度基本相同,其平均密度为(44.7±7.15)个/0.0025mm2。结论本实验所得CBA小鼠耳蜗和前庭测量数据,为进一步定量观察CBA小鼠内耳病理学改变提供了重要的参考依据。

Objective To provide useful reference data of sensory epithelium in the inner ear, the cochlear and vestibular system were carefully measured in CBA mice. Methods Six young CBA mice at three months of age were used for this study. The surface preparations of cochlear basilar membrane and vestibular end-organs were measured under light microscope. The length and the width of basilar membrane and organ of Corti were examined along the cochlear basilar membrane. In addition, the total number and the density of cochlear hair cell along the basilar membrane were also calculated. To evaluate the vestibular end-organs, the total amount of hair cells in macula of saccule and utricle were counted. The hair cell density of striola region and marginal region in saccule and utricle were calculated respectively, and the density of hair cells in cristae in membranous ampulla of three semicircular canals were also counted. Results The total length of the cochlear basilar membrane was 5.76 ±0.196 mm in CBA mice. The width of basilar membrane was 339.1 ±9.87 μm at 1.5 mm, 304.5± 11.82 μm at 3 mm, and 300.1 ±7.22 μm at 5 mm from the cochlear base respectively. This indicated that the width of cochlear basilar membrane was gradually narrowing from base to apex. In contrast, the width of organ of Corti was 37.80±2.24 μm at 1.5 mm, 45.00±2.67 μm at 3 mm, and 52.20 ± 3.16μm at 5 mm from the base respectively, which demonstrated that the width of organ of Corti was gradually increasing from base to apex. The total number of cochlear hair cells in CBA mice was 3116.41 ± 151.91, which included 680.67 ± 17.50 inner hair cells and 2435.8 ± 143.46 outer hair cells. The density of cochlear hair cells was similar across the entire length of the cochlea with a density of 541.1 ±9.36/mm. The density of inner hair cells and outer hair cells were 118.3±2.68/mm and 422.8 ±11.87/mm respectively. The total number of hair cells in macula of utricle and saceule were 3300 ±177.51 and 3045 ± 361.57 respectively. The density of hair cells was lower in striola region than the marginal region in both saccule and utricle. In which, the density of hair cell in striola is 40.2 ±6.59/0.0025 mm2, while in marginal region was 53.2 ±7.18/0.0025 mm2. The density of hair cell in crista of ampulla was 44.7 ± 7.15/0.0025 mm2. Conclusion The reference data from current measurement provide important information for further quantitative analysis in pathological changes in the inner ear in CBA mice.