骨髓间充质干细胞移植治疗大鼠肾脏辐射损伤

Bone marrow mesenchymal stem cell transplantation for treating irradiation-induced injury to the rat kidney

背景:研究发现骨髓间充质干细胞可向包括肾脏系膜细胞在内的肾实质细胞分化,且肾损伤后骨髓间充质干细胞具有修复肾脏结构和功能的作用。目的:观察肾脏辐射损伤大鼠模型接受骨髓间充质干细胞移植后肾脏组织学及功能学变化。设计、时间及地点:细胞学体外实验,于2009-01/10在珠江医院血液科实验室完成。材料:清洁级雄性SD大鼠35只,20只用于制备骨髓间充质干细胞,剩余15只随机分为正常对照组、模型组、细胞移植组,5只/组。方法:全骨髓法分离培养大鼠骨髓间充质干细胞,细胞达90%融合时胰酶消化传代。模型组、细胞移植组大鼠建立辐射损伤模型,接受X射线全身照射,剂量率为500cGy/min,距靶源100cm,每次剂量6Gy,1次/周,连续3周。接受照射完毕后24h,取处于对数生长期的第3代骨髓间充质干细胞,细胞移植组大鼠经尾静脉注射1mL细胞悬液,含3×106个细胞,共3次;正常对照组、模型组大鼠尾静脉注射同等体积的生理盐水。主要观察指标:肾脏组织学苏木精-伊红染色结果,血清和肾脏组织中超氧化物歧化酶及丙二醛的表达,血清中肌酐和尿素氮的表达。结果:①肾脏组织病理显示,模型组肾皮质变薄,间质增多;肾小体分布不均匀;肾小球结构紊乱,肾小球血管及出、入球血管变窄,肾小囊腔部分消失;可见部分肾小球变性硬化表现。细胞移植组肾皮质较模型组明显增厚,结构较清晰,间质充血水肿明显减轻;可见较多完整的肾小体;部分肾小球仍存在变性、硬化表现,可见明显的肾小囊腔。②氧自由基检测结果显示,与模型组比较,细胞移植组大鼠血清和肾脏组织中超氧化物歧化酶的活性均明显升高(P<0.05),丙二醛水平均明显降低(P<0.05)。③肾功能检测结果显示与模型组比较,细胞移植组大鼠血清中肌酐和尿素氮浓度明显降低(P<0.05)。结论:骨髓间充质干细胞移植具有对抗和修复辐射损伤大鼠肾脏的作用,能够有效改善肾脏功能。

BACKGROUND： Bone marrow mesenchymal stem cells （BMSCs） can differentiate into renal parenchymal cells including renal intercapillary cells. BMSCs can repair kidney structure and function after damage. OBJECTIVE： To investigate renal histology and function changes following BMSC transplantation in a rat model of radiation-induced damage. DESIGN, TIME AND SETTING： The cytological in vitro study was performed at the Laboratory of the Department of Hematology, Zhujiang Hospital from January to October 2009. MATERIALS： A total of 35 clean male Sprague Dawley rats were selected. Of them, 20 were used to prepare BMSCs. The remaining was randomly assigned to a normal control, model and cell transplantation groups, with 5 in each group. METHODS： Rat BMSCs were incubated by the whole bone marrow method. When 90% cells were confluent, BMSCs were digested in trypsin for subculture. In the model and cell transplantation groups, rats were used to establish radiation-induced models, and then underwent X-ray general irradiation, at a dose of 500 cGy/min, 100 cm from the target, 6 Gy each, once per week, for consecutively 3 weeks. 24 hours following irradiation, BMSCs of 3 passage were collected at logarithmic phase. In the cell transplantation group, 1 mL cell suspension was infused into the rat caudal vein, containing 3×10^6 cells, totally three times. In the normal control and model groups, rat caudal vein received an equal volume of saline. MAIN OUTCOME MEASURES： The following parameters were measured： results of hematoxylin-eosin staining; serum and kidney malondialdehyde （MDA） content and superoxide dismutase （SOD） activity; serum creatinine and urea nitrogen levels. RESULTS： Kidney histopathology demonstrated thin renal cortex, increased number of mesenchyme, uneven renal corpuscle, and disordered structure of renal glomerulus, narrow renal glomerular vessel, partial disappeared capsular space, and degeneration and sclerosis of some glomerulus in the model group. In the cell transplantation group, renal cortex became thick, with clear structure; interstitial hyperemia and edema was significantly relieved; many complete renal corpuscles were observed; partial renal glomerulus presented degeneration and sclerosis; significant capsular space could be seen. Oxygen free radical examination results showed that compared with the model group, SOD activity was significantly higher （P 〈 0.05）, MDA levels were significantly lower （P 〈0.05） in the cell transplantation group. Renal function examination results demonstrated that compared with the model group, serum creatinine and urea nitrogen levels were significantly reduced in the cell transplantation group （P 〈 0.05）. CONCLUSION： BMSC transplantation can effectively treat renal radiation injury and improve renal function.