肽能神经递质在犬脊髓损伤后神经源性膀胱中的表达及意义

The expression and significance of peptidergic neurotransmitters in neurogenic bladder after spinal cord injury in dogs

目的探讨犬不同脊髓平面损伤后神经源性膀胱时肽能神经递质血管活性肠肽(VIP)、P物质(SP)、降钙素相关基因肽(CGRP)在膀胱中表达的变化规律及意义。方法健康成年雌性家犬14只,分为4组,应用脊髓横断的方法建立犬神经源性膀胱动物模型。A组,胸8～9平面横断脊髓;B组,腰1～2平面横断脊髓;C组,腰7骶1平面横断脊髓;每组4只;对照组2只。术后第4周确定已形成神经源性膀胱后处死动物,采用免疫组化的方法检测膀胱三角区及膀胱前壁VIP、SP、CGRP的表达,计算其表面积密度。结果 SP:A组与对照组比较差异无统计学意义(P>0.05),B组、C组与对照组比较差异有统计学意义(P<0.05)。VIP:A组、B组、C组与对照组比较差异有统计学意义(P<0.05)。CGRP:A组、B组、C组与对照组比较差异有统计学意义(P<0.05)。结论 VIP、CGRP在脊髓损伤后神经源性膀胱中表达较正常对照明显降低,调节VIP、CGRP合成或释放的中枢位于骶上。SP因脊髓损伤平面不同而发生不同变化,提示调节膀胱SP合成或释放的初级中枢在骶髓,脊髓交感神经中枢通过抑制SP的合成或释放来发挥作用。

Objective To investigate the change regulation of expression and significance of peptidergic neurotransmitters including vasoactive intestinal peptide （ VIP）, substance P （SP） and calcitonin gene-related peptide （CGRP） in canine neurogenic bladder after spinal cord injury. Methods 14 clean healthy adult female dogs were randomly divided into four groups. The animal neurogenic bladder models were established by transecting the spinal cord, group A：spinal cord transection plane at T8-9 level ,4 ; group B：spinal cord transection plane at L1, 2 level; group C： spinal cord transection plane at LTS1 level; group D： control group. Four weeks after the transection, the canine neurogenic bladder models were proved to be successful, then the animals were executed, the expressions VIP, SP and CGRP in vesical triangle and anterior wall of urinary bladder were detected by immunuhistochemisty and their surface densities were calculated. Results There was no significant difference in the expression of SP between group A （3.83 ± 0.83 ） and control group （3.93 ±0.72） （ P 〉 0.05 ）, however, there were significantly differences between group B （5.62 ± 0.58 ）, group C （ 1. 25 ± 0.53 ） and control group （3.93± 0.72） （ P 〈 0.05 ）. There were significant differences in the expression of VIP between group A （ 1.72 ± 0.95 ）, group B（ 1.89 ±1.02）, group C （ 1.82 ± 0.95 ） and control group （4.44 ± 0.87 ） （ P 〈 0.05 ）. There were significant differences in the expression of CGRP between group A （1.49 ±0.64） ,group B（ 1.61 ±0.60） ,group C（1.33 ±0.63）and control group（4.42 ± 1.01 ） （ P 〈0.05）. Conclusion The expressions VIP and CGRP in canine neurogenic bladder after spinal cord injury are obviously decreased, as compared with those in normal control group. The central nerve of regulating the synthesis or release of VIP and CGRP is situated above the sacral spinal cord. The expression of SP varies with the different plane levels of spinal cord injury,which suggests that the central nerve of regulating the synthesis or release of SP is located in sacral cord, and spinal cord sympathetic nerve may produce an obvious effect through inhibiting synthesis or release of SP.