干细胞因子联合粒细胞集落刺激因子动员骨髓干细胞促进单侧输尿管梗阻大鼠肾脏损伤的修复

目的 研究干细胞因子（SCF）联合粒细胞集落刺激因子（G-CSF）动员单侧输尿管梗阻（UUO）大鼠骨髓干细胞对肾间质中微血管、纤维化程度和肾功能的影响，并探讨其对微血管影响的可能机制。 方法 128只大鼠按数字随机法分为假手术组（Sham组）、SCF联合G-CSF动员组（SCF-G组）、UUO组、UUO+SCF-G组。于实验第 5、14、21、28天每组各随机抽取8只处死，检测Scr、肾间质CD34阳性表达细胞数目和Ⅷ因子阳性表达细胞数目、肾间质纤维化和间质病理损害积分、肾皮质血管内皮生长因子（VEGF）mRNA和血小板反应蛋白1（TSP-1）mRNA的表达。 结果 (1)UUO组2周时可见到肾间质纤维化伴肾小管周微血管的丢失。（2）UUO+SCF-G组肾间质干细胞归巢数目明显高于UUO组和Sham组（P < 0.05）。（3）UUO+SCF-G组肾小管周微血管指数减少出现的时间晚于UUO组（P < 0.05）。（4）第14、21、28天UUO+SCF-G组间质化纤维程度和肾小管损伤程度均轻于UUO组（P < 0.05）。（5）UUO+SCF-G组术后VEGF mRNA表达下调出现的时间晚于UUO组，且表达均高于同期UUO组 （P < 0.05)。（6）UUO+SCF-G组术后TSP-1 mRNA表达增高出现的时间晚于UUO组，且表达均低于同期UUO组（P < 0.05）。（7）在UUO组和UUO+SCF-G组中，肾小管周微血管指数与Scr、间质纤维化积分和肾小管间质病理积分均呈负相关；肾皮质VEGF mRNA表达与肾小管周微血管指数呈正相关；肾皮质TSP-1 mRNA表达与肾小管周微血管指数呈负相关。 结论 （1）UUO大鼠存在肾小管周微血管丢失，并与肾间质纤维化及间质病理损伤相关。（2）联合应用SCF和G-CSF动员骨髓干细胞可以归巢至受损的肾脏，有助于减少肾小管周微血管丢失，并进而减轻肾间质纤维化和间质损害，保护肾功能。（3）联合应用SCF和G-CSF可以上调肾皮质VEGF mRNA水平和下调TSP-1 mRNA水平，这可能是其促进内皮细胞修复及保护肾间质微血管损伤的机制之一。

Effect of bone marrow stem cells mobilization by SCF combined with G-CSF on renal regeneration and repair in UUO rats

Objective To investigate the effect and possible mechanism of bone marrow stem cell mobilized by stem cell factor (SCF) with granulocyte colony-stimulating factor(G-CSF)on renal peritubular capillary, fibrosis and renal function in unilateral ureteral obstruction (UUO) rats. Methods One hundred and twenty eight healthy male Wistar rats were randomly divided into four groups: Sham group, SCF-G group, UUO group and UUO+SCF-G group. Eight rats of each group were randomly selected and killed on the 5th, 14th, 21st and 28th day. Serum creatinine, CD34 positive cells and factor Ⅷ positive cells in renal interstitium, histopathologic lesion scores of interstitial fibrosis and interstitial pathology in kidney were measured. The mRNA expression of vascular endothelial growth factor (VEGF). and thrombospondin-1 (TSP-1) in the renal cortex was detected. Results (1) The renal interstitial fibrosis anti the loss of peritubular capillary were observed in UUO group after two weeks. (2) The number of bone marrow stem cells homing to renal interstitium in UUO +SCF-G group was significantly higher than that in UUO and Sham groups (P<0.05). (3) The loss of peritubular capillary in UUO+SCF-G group appeared later than that in UUO group (P<0.05). (4) The interstitial fibrosis and tubule injury was milder in UUO+SCF-G group than that in UUO group (P<0.05). (5) The decrease of VEGF mRNA expression of renal cortex in UUO +SCF-G group was seen later than that in UUO group. VEGF mRNA expression in UUO+SCF-G group was higher than that in UUO group. (6) The increase of TSP-1 mRNA expression of renal cortex in UUO+SCF-G group was seen later than that in UUO group. TSP-1 mRNA expression in UUO+SCF-G group was lower than that in UUO group (P<0.05). (7) In UUO and UUO+SCF-G groups, peritubular capillary index was negatively correlated with serum creatinine, interstitial fibrosis and interstitial lesion scores. VEGF mRNA expression of renal cortex was positively correlated with peritubular capillary index, and TSP-1 mRNA expression of renal cortex was positively correlated with peritubular capillary index. Conclusions (1)The loss of peritubular capillary is found in UUO group, and is correlated with interstitial fibrosis and interstitial lesion. (2) Application of SCF with G-CSF can effectively motivate stem cells to injured renal tissue, contribute to decrease the loss of peritubular capillary, lessen interstitial fibrosis and interstitial lesion, and ameliorate renal function. (3) Application of SCF with G-CSF can up-regulate VEGF mRNA expression and down-regulate TSP-1 mRNA expression, which may contribute to promote the repair of endothelial cells and protect peritubular capillary.