脂多糖联合低剂量海人藻酸诱导建立幼鼠热性惊厥脑损伤模型

Establishment of Brain Damage Model with Febrile Seizures in Developing Rats Induced by Lipopolysaccharide and Low-Dose Kainic Acid

目的探讨应用脂多糖(LPS)联合低剂量海人藻酸(KA)腹腔注射建立大鼠热性惊厥(FS)脑损伤模型的方法。方法取64只14日龄新生SD大鼠随机分为4组:LPS+KA组(A1B1组,n=16),9 g.L-1盐水(NS)+NS组(A2B2组,n=16),NS+KA组(A2B1组,n=16),LPS+NS组(A1B2组,n=16),采用LPS联合低剂量KA腹腔注射的方法诱导大鼠高热惊厥。HE染色观察各组大鼠海马神经元显微结构的改变,原位末端标记法(TUNEL)检测各组大鼠海马神经细胞凋亡数的变化。结果 A1B1组16只大鼠均出现惊厥,而其他3组大鼠不出现惊厥,惊厥发作时肛温为(39.3±0.4)℃,与人类相似。HE染色发现A1B1组各时间点大鼠海马组织切片上出现不同程度的神经元变性及丢失,惊厥后24 h病理改变最明显。A1B1组在惊厥后24 h、48 h时间点海马CAl区TUNEL阳性细胞数明显升高,与A1B2组、A2B1组、A2B2组比较差异均有统计学意义(Pa<0.01)。结论 LPS联合低剂量KA腹腔注射诱导大鼠FS与人类FS有许多相似之处,大鼠长时间FS发作可导致海马神经元凋亡数增加,该模型是进一步研究高热惊厥脑损伤及其机制的理想模型。

Objective To explore the method for establishing a brain damage model with febrile seizures （FS） in developing rats induced by lipopolysaccharide （LPS） and low - dose kainic acid （KA）. Methods Sixty - four cases of 14 - day - old Sprague - Dawley rats were randomly divided into 4 groups ： LPS ± KA group （ A1 B1 group, n = 16 ） , normal sodium （NS） ± NS group （ A2 B2 group, n = 16 ）, N S ± KA group （ A2B1 group,n = 16）, LPS ± NS group （ A1B2 group, n = 16）. LPS combined with KA of intraperitoneal injection as used to induce convul- sions with fever. Then the histopathology changes in hippocampus were viewed by HE staining and electronmicroscope, the neuron apoptosis was observed by TdT - mediated dUTP nick end labeling （TUNEL）. Results In A1B1 group,16 rats all appeared seizures,while the rats in the other 3 group were all without convulsions, the average rectal temperature of seizures was （ 39.3 ± 0.4 ） ℃, similar to human. HE staining discovered that there were different degrees degeneration and cell loss in hippocampus neurons in FS group, 24 h neurons presented most shape. In A1 B1 group, the 24 h time point after seizure ,TUNEL- positive cells in hippocampus CA1 region increased significantly, compared with that in the A1 B2 group, A2B1 group and A2B2 group, the differences were significant （P 〈 0.01 ）. Conclusions There are much similarities between LPS combined intraperitoneal injection of KA - induced FS in rats and FS in humans. Prolonged FS in rats can increase the number of apoptosis in hippocampal neurons in the developing rats. Therefore, this model is ideal model for the mechanisms involved in the genesis of FS and their long - term consequences damage on brain development.