Objective To examine the expression of miR145 and myocardin in vascular injuries of children with lupus nephritis ( LN) , and to discuss their roles in the development of vascular injuries of LN children.Methods 49 systemic lupus erythematosus ( SLE) inpatients who were diagnosed with LN in the Department of Pediatrics in the Second Xiangya Hospital from January 2008 to September 2015 were enrolled in this study.All patients underwent renal biopsy.Immunofluorescence, light microscopic and electron microscopic examination were given to biopsy tissues routinely.According to 2002—2003 typing criteria of LN that jointly revised by International Society of Nephrology ( ISN) /Renal Pathology Society ( RPS) , pathological typing was conducted, and there were 5 cases in typeⅡ, 7 in typeⅢ, 9 in typeⅢ+Ⅴ, 17 in typeⅣand 11 in typeⅣ+Ⅴ.The degree of vascular injury was evaluated by the proportion of tunica media, and the subjects were divided into 14 mild cases, 19 moderate cases, and 16 severe cases.According to KATAFUCHI and other methods of evaluation, semi-quantitative scores of glomerular damage and renal interstitial injury were made; the level of serum myocardin was measured by double antibody sandwich method; and the expression of miR-145 was detected by in situ hybridization method.Results There were significant differences in the scores of glomerular damage and renal interstitial injury among children of different pathological types ( P<0.05 ) .There was a positive linear correlation between the score of glomerular damage and the score of renal interstitial injury ( r=0.961, P<0.01) .The level of serum myocardin was significantly different between children with different vascular injury degrees and pathological types ( P <0.05 ) .The expression of miR -145 in renal blood vessels was significantly different between children with different vascular injury degrees and pathological types ( P<0.05) .There was a positive linear correlation between the level of serum myocardin and the expression of miR-145 in renal blood vessels (r=0.782, P<0.01); and the level of serum myocardin and the expression of miR-145 in renal blood vessels were negatively correlated with the degree of vascular injuries (values of r were -0.728, and -0.790 respectively; P<0.01) .Conclusion With the increase of the degree of vascular injuries, the level of serum myocardin and the expression of miR -145 in renal blood vessels were both decreased, the two can not only be used to assess the degree of renal vascular lesions ( RVLs) of children with LN, but also may be a new target for the treatment of renal vascular injury in LN.%目的：观察狼疮性肾炎（ LN）患儿血管损伤中心肌素与miR－145的表达情况，并探讨二者在LN患儿血管损伤发生中的作用。方法选取2008年1月—2015年9月在湘雅二医院儿科住院的系统性红斑狼疮（ SLE）患儿中确诊为LN的患儿49例，均行肾活检，活检组织常规进行免疫荧光、光镜及电镜检查。依据国际肾脏病协会（ ISN）和肾脏病理学会（ RPS）2002—2003年联合修订的ISN／RPS 2003 LN分型标准进行病理分型，共分为Ⅱ型5例、Ⅲ型7例、Ⅲ＋Ⅴ型9例、Ⅳ型17例、Ⅳ＋Ⅴ型11例。以中膜比例评价血管损害程度，并分为轻度14例、中度19例、重度16例。依据KATAFUCHI等的评价方法对肾小球、肾间质损害进行半定量积分；采用双抗体夹心法测定血清心肌素水平；采用原位杂交法检测miR－145表达。结果不同病理分型患儿肾小球、肾间质损害积分间差异均有统计学意义（P＜0．05）。肾小球损害积分与肾间质损害积分呈直线正相关（r＝0．961， P＜0．01）。不同血管损害程度、病理分型患儿血清心肌素水平间差异均有统计学意义（P＜0．05）。不同血管损害程度、病理分型患儿肾内血管miR－145表达间差异均有统计学意义（P＜0．05）。血清心肌素水平与肾内血管miR－145表达呈直线正相关（r＝0．782， P＜0．01）；血清心肌素水平、肾内血管miR－145表达与血管损害程度呈直线负相关（ r值分别为－0．728、－0．790， P＜0．01）。结论随着血管损害程度的增加血清心肌素水平和肾内血管miR－145表达均降低，二者不仅可用于评估LN患儿肾内血管损害（ RVLs）程度，也可能是LN肾血管损伤治疗的新靶点。
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