肠道菌群变化对大鼠激素性股骨头坏死造模效果的影响

Effects of differences in intestinal flora on steroid-induced osteonecrosis of the femoral head in SD rats

目的探究激素性股骨头坏死(GA-ONFH)模型大鼠的肠道菌群变化及其对造模效果的影响。方法40只雄性SD大鼠随机分为空白对照组、抗生素组(ABX组)、激素性股骨头坏死模型组(GA-ONFH模型组)、抗生素+激素性股骨头坏死模型组(ABX+GA-ONFH组),每组10只。ABX组和ABX+GA-ONFH组持续给予抗生素溶液洗脱肠道微生物1周。1周后GA-ONFH模型组和ABX+GA-ONFH组给予脂多糖(LPS)+地塞米松腹腔注射建立早期GA-ONFH模型,空白对照组和ABX组腹腔注射等量生理盐水,连续注射6周。收集大鼠粪便和股骨头样本,基于16S rDNA扩增子测序分析大鼠肠道菌群的构成及丰度,使用micro-CT和HE染色观察早期GA-ONFH造模效果,评估肠道菌群对GA-ONFH造模效果的影响。结果与空白对照组比较,GA-ONFH模型组大鼠肠道菌群丰度发生改变,其中拟杆菌门丰度明显下调,而厚壁菌门丰度明显上调,差异有统计学意义(P<0.05);在科水平上,普雷沃菌科、梭状芽胞杆菌科、消化球菌科、理研菌科和克里斯滕森菌科的丰度明显下调,而葡萄球菌科的丰度明显上调,差异有统计学意义(P<0.05);在属水平上,另枝菌属、UCG-005、梭状芽胞杆菌属、拟普雷沃菌属和普雷沃菌属的丰度明显下调,而葡萄球菌属和Frisingicoccus的丰度明显上调,差异有统计学意义(P<0.05)。Micro-CT断层扫描显示,GA-ONFH模型组和ABX+GAONFH组均出现软骨下骨小梁硬化;HE染色显示,ABX+GA-ONFH组较GA-ONFH模型组更早出现骨小梁断裂,表明抗生素洗脱肠道微生物后,大鼠GA-ONFH造模效果更加显著。结论GA-ONFH模型大鼠的肠道菌群发生了明显变化,且该变化可能影响早期GA-ONFH的发生。

Objective To explore the differences in the intestinal flora between the glucocorticoid-associated osteonecrosis of the femoral head(GA-ONFH)rat model and its effect on the modeling results of GA-ONFH.Methods Forty SD rats were randomly divided into four groups(n=10 for each group):control group,antibiotic(ABX)group,GA-ONFH model group,and ABX+GA-ONFH group.The ABX group and ABX+GA-ONFH group were continuously treated with an antibiotic solution to elute intestinal microorganisms for one week.One week later,the GA-ONFH model group and ABX+GA-ONFH group were intraperitoneally injected with lipopolysaccharide and dexamethasone to create an early GA-ONFH model;while the control group and ABX group received an equal volume of normal saline for six weeks.After six weeks,to evaluate correlation between intestinal flora and GA-ONFH modeling,the following experiments were conducted and analyzed from intestinal contents and femur samples:1)the composition and abundance of fecal flora based on 16S rDNA amplicon sequencing technology;2)Micro-CT and HE staining to observe the modeling results of early GA-ONFH.Results Compared with control group,the abundance of intestinal flora in GA-ONFH model group changed,and the abundance of Bacteroidetes was significantly down-regulated and Firmicutes was significantly up-regulated,with statistical significance(P<0.05);at the family level,the abundance of Prevotellaceae,Clostridia-UCG-014,Peptococcaceae,Rikenellaceae,and Christensenellaceae were significantly down-regulated,the abundance of Staphylococcaceae was significantly up-regulated,and the differences were statistically significant(P<0.05);at the genus level,the abundance of Alistipes,UCG-005,Clostridia_UCG-014,Alloprevotella,and Prevotellaceae_UCG-001 were significantly downregulated,the abundance of Staphylococcus and Frisingicoccus were significantly up-regulated,with statistical significance(P<0.05).Micro-CT tomography showed subchondral trabecular sclerosis in both the GA-ONFH model group and ABX+GA-ONFH group after modeling.HE staining showed that trabecular bone fracture occurred earlier in the ABX+GA-ONFH group than in the GAONFH model group.After the gut microbial abundance was removed,the rat GA-ONFH modeling effect was more significant.Conclusion The intestinal flora of GA-ONFH model rats changed,and the change of intestinal flora may affect the occurrence of early GA-ONFH.