Athens University School of Medicine, Attikon University Hospital, Department of Cardiac Surgery, Athens, Greece.
J Surg Res. 2012 Jan;172(1):68-76. doi: 10.1016/j.jss.2010.07.039. Epub 2010 Sep 17.
Sympathetic innervation exerts marked effects on vascular smooth muscle cells, including a short-term homeostatic (vasoconstrictor) and a direct trophic action promoting differentiation. However, the role of sympathetic nervous system in long-term structural and functional modulation of the aortic wall is yet undefined.
Six Landrace pigs underwent bilateral thoracic sympathectomy from the stellate to T8 ganglion, whereas 10 pigs underwent sham operation. Animals were sacrificed 3 mo postoperatively. Histometrical examination was performed on specimens from the thoracic (TA) and abdominal aorta (AA) utilizing an image-processing system. A uniaxial tensile tester was utilized for biomechanical evaluation; parameters of extensibility, strength, and stiffness of aortic tissue were calculated.
Structural aortic remodeling of sympathectomized animals was observed, including increased inner aortic diameter in TA (15.3 ± 0.4 versus 10.4 ± 0.2 mm, P < 0.001) and AA (6.7 ± 0.3 versus 5.3 ± 0.2 mm, P = 0.002), and increased wall thickness in TA (2.0 ± 0.1 versus 1.6 ± 0.1 mm, P < 0.001) but not AA. Microscopic image analysis revealed increased elastin (TA: 50.1 ± 1.1 versus 29.7% ± 0.6%, P < 0.001; AA: 20.4 ± 2.1 versus 16.3% ± 0.6%, P = 0.03) and collagen density (only in TA: 22.0 ± 0.9 versus 15.4% ± 0.5%, P < 0.001), and decreased smooth muscle density (TA: 27.6 ± 1.3 versus 54.9% ± 0.7%, P < 0.001; AA: 57.2 ± 1.5 versus 63.4% ± 0.8%, P < 0.001). Sophisticated biomechanical analysis demonstrated that following sympathectomy, TA was equally extensible but manifested augmented strength (1344 ± 73 versus 1071 ± 52 kPa, P = 0.004) and stiffness (6738 ± 478 versus 5026 ± 273 kPa, P = 0.003), in accordance with extracellular matrix protein accumulation in that region. Differences in the AA were non-significant.
Chronic thoracic sympathetic denervation causes significant structural and biomechanical remodeling of the thoracic aorta. Possible clinical implications for patients undergoing thoracic sympathectomy or chronically treated with sympathetic blockers require further investigation.
交感神经对血管平滑肌细胞有明显的影响，包括短期的稳态（血管收缩）和促进分化的直接营养作用。然而，交感神经系统在主动脉壁的长期结构和功能调节中的作用尚不清楚。
六头长白猪接受了从星状到 T8 神经节的双侧胸交感神经切除术，而 10 头猪接受了假手术。动物在术后 3 个月被处死。利用图像处理系统对胸主动脉（TA）和腹主动脉（AA）的标本进行组织学检查。采用单轴拉伸试验机进行生物力学评价；计算主动脉组织的延展性、强度和刚度等参数。
交感神经切断术后观察到主动脉结构重塑，包括 TA 内主动脉直径增加（15.3 ± 0.4 毫米比 10.4 ± 0.2 毫米，P < 0.001）和 AA（6.7 ± 0.3 毫米比 5.3 ± 0.2 毫米，P = 0.002），TA 壁厚度增加（2.0 ± 0.1 毫米比 1.6 ± 0.1 毫米，P < 0.001），但 AA 无变化。显微镜图像分析显示弹性蛋白增加（TA：50.1 ± 1.1%比 29.7% ± 0.6%，P < 0.001；AA：20.4 ± 2.1%比 16.3% ± 0.6%，P = 0.03）和胶原密度增加（仅在 TA：22.0 ± 0.9%比 15.4% ± 0.5%，P < 0.001），平滑肌密度降低（TA：27.6 ± 1.3%比 54.9% ± 0.7%，P < 0.001；AA：57.2 ± 1.5%比 63.4% ± 0.8%，P < 0.001）。复杂的生物力学分析表明，交感神经切断术后 TA 具有相同的延展性，但强度增加（1344 ± 73 千帕比 1071 ± 52 千帕，P = 0.004）和刚度增加（6738 ± 478 千帕比 5026 ± 273 千帕，P = 0.003），这与该区域细胞外基质蛋白的积累有关。AA 的差异无统计学意义。
慢性胸交感神经切断导致胸主动脉明显的结构和生物力学重塑。需要进一步研究接受胸交感神经切除术或长期接受交感神经阻滞剂治疗的患者的可能临床意义。
