内毒素血症小鼠骨骼Toll样受体4基因的变化

The change in Toll-like receptor 4 gene expression in skeleton of endotoxemia mice

目的通过检测内毒素血症模型动物骨骼相关基因表达变化，进一步明确内毒素对机体的损害机制，为下一步研究骨骼变化对脏器产生何种影响奠定基础。方法腹腔注射内毒素脂多糖（LPS）制作内毒素血症小鼠模型。将48只小鼠随机分为正常组和LPS处理4、6、8、12、24、48和72h组，每组6只。采尾血计数全血白细胞；取眼眶血检测肝、肾功能；用逆转录-聚合酶链反应（RT—PCR）检测骨骼中TLR4mRNA表达；苏木素-伊红（HE）染色，镜下观察骨骼病理学变化。结果与正常组比较，LPS4h组白细胞计数显著下降（P〈0．01），之后逐渐升高，于72h时显著高于正常组（P〈0．05）；LPs4h和6h组丙氨酸转氨酶（ALT）水平显著升高（P均〈0．05），于8h降至正常水平（P〉0．05）；LPS6h组血尿素氮（BuN）水平逐渐升高（P〈0．05），于8h达峰值（P〈0．05），然后下降，12h趋于正常（P〉0．05）；LPS6h组TLR4mRNA表达增加（P〈0．01），24h达峰值（P〈0．01），然后逐渐下降，72h仍处在较高水平（P〈0．05）。LPS作用于骨骼后，HE染色显示骨骼无明显改变。结论内毒素血症中骨骼TLR4mRNA表达量显著增加。

Objective To explore the changes in gene expression of bone in endotoxemia in mice. Methods Lipopolysaccharide （LPS） was injected intraperitoneally to reproduce an endotoxemia model in mice. Forty-eight mice were randomly divided into eight groups： normal group, 4, 6, 8, 12, 24, 48 and 72 hours after LPS injection groups, with 6 mice in each group. To evaluate endotoxemia whole blood was collected for leukocytic count, eye sockets blood was obtained for liver and renal functions tests, mRNA expression level of Toll-like receptor 4 （TLR4） in bone was determined by reverse transcription-polymerase chain reaction （RT-PCR） assay. The pathological changes of bone and tissue slides were prepared with hematoxylin and eosin （HE） staining for observing under microscope. Results Compared with normal group, leukocyte count of 4-hour LPS-treated group was significantly decreased （P〈0. 01）. However, after 4 hours, leukocyte count became higher gradually and remained at high level at 72 hours compared with that of normal group （P〈0.05）. Compared with normal group, alanine aminotransferase （ALT） level reached to a high level in LPS-treated groups at 4 hours and 6 hours （both P〈0. 05）, and then decreased gradually showing a tendency to return to normal level after 8 hours （P〉0. 05）. Blood urea nitrogen （BUN） was increased at 6 hours （P〈0.05）, reaching to the highest level at 8 hours （P〉0. 05） and tended to become normal level after 12 hours （P〉0. 05）. Six hours after LPS treatment, the expression of TLR4 mRNA was enhanced （P〈0. 01） and reached the peak at 24 hours （P〈0.01）, and it remained at a high level at 72 hours （P〈0.05）. However, there were no significant pathological changes in bone structure after LPS treatment. Conclusion Expression level of TLR4 mRNA in bone is significantly increased in endotoxemia mice.