假狂犬病毒跨突触示踪胸髓损伤后膀胱神经支配通路变化的研究

Effect of spinal cord injury on urinary bladder spinal neural pathway: a retrograde transneuronal tracing study with Pseudorabies virus

目的利用假狂犬病毒(PRV)跨突触示踪技术,研究胸髓横断所致的急、慢性脊髓损伤(SCI)对膀胱脊髓神经支配通路的影响。方法76只SD大鼠随机分为4组:non-SCI、SCIa、SCIb和SCIc组。SCIa、SCIb和SCIc组大鼠完全横断脊髓,饲养不同时间后,膀胱壁内注射PRV;non-SCI组正常大鼠膀胱壁内注射PRV,一定时间点后心脏灌注固定取材。链霉卵白素-过氧化物酶(SP)免疫组织化学方法显示背根神经节(DRG)和脊髓切片中PRV阳性神经元。图像分析软件统计各组PRV阳性神经元数目和面积。结果SCIb和SCIc膀胱重量显著增加(P<0.001);Non-SCI和SCI大鼠PRV示踪的时限性和分布相似;SCI大鼠病毒标记的DRG细胞面积显著增加(P<0.001)。慢性SCI大鼠在注射PRV后第3天L6和S1节段后角标记细胞数显著增加,注射后第4天L6和S1节段标记的运动神经元数也显著增加。结论急性和慢性脊髓损伤不影响大鼠膀胱的PRV示踪特性。慢性SCI大鼠膀胱排尿反射通路出现显著重组。

Objective To determine the effect of acute and chronic spinal cord injury （SCI） resulted from thoracic cord transection on the urinary bladder spinal neural pathway. Methods 76 adult Sprague-Dawley rats were randomly divided into 4 groups, non-SCI, SCIa, SCIb and SCIc respectively. The non-SCI rats underwent no surgical procedure except Pseudorabies virus （PRV） tracer injection into the bladder tissue, while the rats of other groups were spinalized and given PRV injection at different time after SCI. Transcardiac perfusion fixation was done in appropriate survival periods after PRV injection. Then sections of dorsal root ganglion （DRG） and spinal cord were processed for visualization of virus by the Streptavidin-Peroxidase （SP） immunohistochemical procedure. All sections were measured with the Olympus Cue-2 image analysis system. Results The bladder weights in SCIb and SCIc groups markedly increased （P〈0. 001）. The time-ordered flow charts of PRV tracing were similar in the non-SCI rats and in the SCI rats. The cross-sectional area of the labeled DRG cell profiles increased significantly after SCI （P〈0. 001）. The number of labeled cells in dorsal horn in L6 and S1 segments 3 days after PRV injection markedly increased in chronic SCI rats, and so did the number of labeled motor neurons 4 days post-injection. Conclusion The acute and chronic SCI have little effect on the process of virus transneuronal transport below the level of lesion. Subsequent to chronic SCI, marked reorganization of the micturition reflex pathways occurs.