大鼠脊髓损伤痉挛性膀胱中神经肽含量的观察

Observation of neuropeptides in bladder after spinal cord injury in rats

目的观察SD大鼠脊髓损伤痉挛性膀胱形成后膀胱逼尿肌内神经肽Y（NPY）、P物质（sP）和血管活性肠肽（VIP）表达的改变，探讨其与脊髓损伤痉挛性膀胱的关系。方法成年雄性SD大鼠20只，按随机数字表法分为脊髓损伤组（n=10）和对照组（n=10），脊髓损伤组采用重物坠落法制作大鼠胸段脊髓挫伤模型，对照组只打开椎板不造成脊髓损伤，术后1周所有大鼠行膀胱压力容量测定，确定痉挛性膀胱形成。取膀胱逼尿肌组织，分别行神经纤维银染和NPY、SP、VIP免疫组织化学染色，用测量累积吸光度（IA）的半定量方法评估脊髓损伤及对照组大鼠膀胱逼尿肌内神经肽表达的改变情况。结果脊髓损伤组大鼠造模术后1周平均膀胱最大容量为（0．71±0．24）ml，较正常对照组（1．99±0．42）ml明显降低；平均最大逼尿肌压力值为（32．3±3．1）cmH，0（1emH2O=0．098kPa），较正常对照组（21．0±3．0）cmH20明显增高；平均膀胱顺应性为（0．020±0．009）ml／cmH，0，较正常对照组（0．090±0．020）mL／cmH：0明显降低；上述差异均具有统计学意义（均P〈0．01）。脊髓损伤痉挛性膀胱逼尿肌内神经纤维平均含量值为2．58±0．13，较正常对照组值（5．65±0．26）明显减少；NPY平均M值为3．2±0．5，较正常对照组值（7．3±0．7）明显减低；SP平均¨值为1．7±0．4，较正常对照组值（5．0±0．4）明显减低；VIP平均M值为2．1±0．4，较正常对照组值（5．5±0．5）明显减低；上述差异均具有统计学意义（均P〈0．叭）。结论大鼠脊髓损伤痉挛性膀胱形成后膀胱逼尿肌内神经肽物质含量明显减少，可能与脊髓损伤后神经源性膀胱形成有关。

Objective To observe the altered expressions of neuropeptide Y, substance P and vasoactive intestinal peptide in detrusor of SD rats after spinal cord injury and explore the relationship of the above neuropeptides and neurogenic bladder after spine cord injury. Methods Twenty male clean-grade SD rats, aged 6 weeks, were selected and randomized into spinal cord injury group （n = 10） and control group （ n = 10）. Rats in spinal cord injury group were smashed at T10 to cause spinal cord incomplete injury model by the weight drop method while laminectomy alone without smashing was administered in control group. At Week 1 post-operation, all rats were assessed by the maximum bladder capacity, bladder compliance and detrusor pressure for the confirmation of spastic bladder. And all detrusor specimens were marked with argentation and immunohistochemistry for the analyses of nerve fibers, neuropeptide Y, substance P and vasoactive intestinal peptide. The results were evaluated with semiquantitative method to observe the contents of nerve fiber and neuropeptides. Results At Week 1 post-operation, the mean maximum bladder compacity, mean maximum detrusor pressure and mean compliance in SCI rats was 0. 71 ± 0.24 ml, 32. 27 ±3.12 cm H20 and 0. 020 ± 0. 009 ml/cm H20 versus 2. 0 ± 0.4 ml, 21.0 ± 3.0 cm H20 and 0. 090 ± 0. 020 ml/cm H2O in normal control group respectively. And the differences were statistically significant （P〈0.01）. Meanwhile, the mean content of nerve fibers of neurogenie bladder decreased markedly than that of normal control group （ 2. 58 ± 0. 13 vs 5.65 ± 0. 26 ）. As compared with the normal control group, the expressions of neuropeptide Y, substance P and vasoactive intestinal peptide （mean integrated optical density ：3.2 ± 0. 5, 1.7 ± 0.4 and 2. 1 ± 0. 4 respectively） decreased dramatically in SCI rats. And the differences were statistically significant （ P 〈 0. 01 ）. Conclusion The number of nerve fibers and the content of neuropeptides significantly decrease in neurogenic bladder after spinal cord injury in rats. The reduction of neuropeptides may be correlated with the formation of neurogenic bladder after spinal cord injury.