He Si-chun, Chen Zhongj-ie, Ma Ning
Department of Physiology, Medical College of Jinan University, Guangzhou, China.
Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2010 Feb;26(1):77-81.
To probe the changes of fast component of brainstem auditory evoked potentials (FC-BAEP), slow component of brainstem auditory evoked potentials (SC-BAEP) and the mitochondrial ultrastructures of the neurons in the brainstem in the rat pups with hyperbilirubinemia.
7 days old SD rat pups were randomly divided into control group (C, 17 rat pups) and two test groups (T1, 17 rat pups and T2, 17 rat pups). Bilirubin solutions (2 g/L) were injected into the abdominal cavity of the rat pups in the group T1 and T2 at the postnatal day 7 and 10. Six hours after the second injection, seven rat pups of each group were randomly selected to test serum bilirubin concentration via a micro-gauge. FC-BAEP and SC-BAEP were examined with an evoked potential recorder in the rest rat pups of each group at postnatal day 17 and 20. At the postnatal day 20, the endocardial perfusion was performed in these rat pups for the fixation of the brain, and then the brains were taken out. The cochlear nuclei were used for observation via electron microscope.
Six hours after the injection of bilirubin solution at the postnatal day 10, the serum bilirubin concentrations of the rat pups in group T1 and T2 were increased significantly. Except for II-IV inter-peak latency(IPL), all the peak latency(PL) and IPL of FC-BAEP evoked via three sound stimulating rates (10/s, 40/s,80/s) at the postnatal day 17 prolonged significantly in the rat pups of group T1 and T2, and the PL in group T2 were much longer than that in group T1. Except for II-IV IPL of FC-BAEP evoked via sound stimulating rates of 10/s and 40/s, all the PL and IPL at the postnatal day 20 prolonged significantly in the rat pups of group T1 and T2. The PL of SC-BAEP evoked via sound stimulating rate of 10/s at the postnatal day 17 and 20 in the rat pups of group T1 and T2 prolonged significantly, and the PL at the postnatal day 17 in group T2 were much longer than that of group T1. The changes of mitochondria of the neurons in the cochlear nuclei at the postnatal day 20 in the rat pups of group T1 and T2 were characterized by swell, the slurred membranes, the broken crista and so on.
There were the abnormal changes of FC-BAEP, SC-BAEP and the mitochondrial ultrastructures of the neurons in the brainstem in the rat pups with hyperbilirubinemia. The PL and IPL of FC-BAEP and SC-BAEP could be taken as the objective and sensitive indexes for early monitoring the bilirubin-induced hearing loss and brain injury.
探讨高胆红素血症幼鼠脑干听觉诱发电位快成分（FC-BAEP）、慢成分（SC-BAEP）及脑干神经元线粒体超微结构的变化。
将7日龄SD幼鼠随机分为对照组（C组，17只）和两个试验组（T1组，17只；T2组，17只）。于出生后第7天和第10天，向T1组和T2组幼鼠腹腔注射胆红素溶液（2 g/L）。第二次注射后6小时，每组随机选取7只幼鼠，用微量血糖仪检测血清胆红素浓度。出生后第17天和第20天，用诱发电位记录仪对每组其余幼鼠进行FC-BAEP和SC-BAEP检测。出生后第20天，对这些幼鼠进行心内灌注固定大脑，然后取出大脑。取耳蜗核用于电镜观察。
出生后第10天注射胆红素溶液6小时后，T1组和T2组幼鼠血清胆红素浓度显著升高。出生后第17天，T1组和T2组幼鼠在三种声刺激率（10/s、40/s、80/s）诱发的FC-BAEP中，除Ⅱ-Ⅳ峰间潜伏期（IPL）外，所有峰潜伏期（PL）和IPL均显著延长，且T2组的PL比T1组长得多。出生后第20天，T1组和T2组幼鼠在声刺激率为10/s和40/s诱发的FC-BAEP中，除Ⅱ-Ⅳ IPL外，所有PL和IPL均显著延长。出生后第17天和第20天，T1组和T2组幼鼠在声刺激率为10/s诱发的SC-BAEP的PL显著延长，且出生后第17天T2组的PL比T1组长得多。出生后第20天，T1组和T2组幼鼠耳蜗核神经元线粒体的变化表现为肿胀、膜模糊、嵴断裂等。
高胆红素血症幼鼠存在FC-BAEP、SC-BAEP及脑干神经元线粒体超微结构的异常改变。FC-BAEP和SC-BAEP的PL和IPL可作为早期监测胆红素所致听力损失和脑损伤的客观、敏感指标。
