低分子肝素对呼吸道合胞病毒肾病大鼠模型的影响

Effects of Low-Molecular-Weight Heparin on Respiratory Syncytial Virus Nephropathy in Rats

目的研究呼吸道合胞病毒(RSV)感染对肾小球基底膜的损伤机制;低分子肝素(LMWH)对RSV致大鼠蛋白尿及肾小球结构改变的减轻及保护机制。方法以6×106空斑形成单位(PFU)RSV鼻腔滴注及腹腔注射,LMWH400IU/kg腹腔注射接种SD大鼠。实验组A先接种RSV3d,后予LMWH11d;实验组B先予RSV和LMWH的混合悬液3d,后予LMWH11d;实验组C连续予LMWH14d,期间于d4、d5、d6接种RSV;RSV组和对照组分别接种RSV和DMEM3d。观察肾组织形态学改变;分析24h尿蛋白定量及血生化学指标。原位杂交检测肾组织RSVRNA表达。结果1.实验组A、B、C与对照组比较尿蛋白无明显增高,RSV组接种后尿蛋白逐渐增高;2.实验组A、B、C与对照组比较血清蛋白、尿素氮、肌酐、胆固醇均无明显差异(Pa>0.05),而RSV组与实验组A和对照组比较,血清蛋白降低,同其余各组比较,尿素氮增高(P<0.05);3.光镜及电镜下实验组A、B、C与对照组比较,肾小球结构无明显改变,RSV组部分肾小球充血肿胀,足突肿胀、融合;4.原位杂交:实验组A、B、C肾组织原位杂交可见RSV阳性信号表达,但较RSV组弱。结论RSV感染细胞机制是通过阴阳电荷吸引作用与细胞表面硫酸乙酰肝素(HS)链结合。LMWH能与肾脏靶细胞HS竞争结合RSV,有效阻止RSV对大鼠肾细胞的感染,保护肾小球不被破坏,减轻蛋白尿。

Objective To explore the mechanism of glomerular basement membrane damaged by respiratory syncytial virus（ RSV）, through investigating the effects of low -molecular- weight heparin（LMWH） on proteinuria and changes of glomerular structure of RSV nephropathy in rats. Methods SD rats were inoculated intranasally and intraperitoneally with 6 × 10^6 plaque forming unit（PFU） RSV and LMWH 400 IU/kg. Group A ： RSV was given in the first 3 days, and follow days LMWH was given for 11 days; group B ： the mixture of RSV and LMWH was given for 3 days ,and then LMWH was given for 11 days; group C ： LMWH was continuously given throughout the experiment and on the 4^th ,5^th ,6^th day RSV was also given;group RSV and control group were respectively inoculated by RSV and DMEM for 3 days. The renal histology was observed by light miexoscope and electron microscope. Meanwhile, the urinary protein and serum parameters were measured. The RSV RNA was determined by in suit hybridization. Results 1. There was no significant increase in proteinuria in the LMWH - treated groups compared with the con- trols, but that of group RSV gradually increased after RSV inoculation. 2. There was a decrease in albumin and an increase in blood urea nitrogen of group RSV only, but there was no difference of creatinine and total cholesterol statistically in all groups （ Pa 〉 0.05 ）. 3. Under light microscope, there was no change of the glomeruli detected in all of the LMWH -treated groups compared with the controls ,while congestion and swelling in part glomeruli of group RSV were observed significantly. 4. Under electron microscope, glomerular structures of the LMWH - treated groups were almost normal compared with the control, while extensive foot process effacement was observed in group RSV under an electron microscope. 5. RSV RNA signal expressed weaker in the LMWH - treated groups than in group RSV. Condualons Positive charged RSV destroys the glomerular filtration barrier through its electrostatic interaction with the negative charged heparan sulfate（HS） of GBM. LMWH, as the analog of HS, charged with anion, competes with GBM HS to combine with RSV to keep the glomeruli from being infected and destroyed, and then reduce the proteinuria.