高脂对兔阴茎海绵体平滑肌细胞含量及结构的影响

The content and ultrastrucal changes of smooth muscle cell corpus of hyperlipidemia rabbit cavernous

目的观察高脂诱导血管性ED家兔阴茎海绵体平滑肌细胞(smooth muscle cell,SMC)含量变化以及海绵体组织超微结构的改变情况。方法8只性成熟雄性新西兰家兔随机分两组,每组各4只。对照组喂以正常饮食,模型组采用高脂、高胆固醇饮食结合球囊导管扩张双侧髂内动脉法建立血管性ED模型。第8周时切取阴茎海绵体组织,HE及特殊染色处理后在光镜、透射电镜下观察,计算机辅助彩色图像分析平滑肌及胶原构成百分比。RT-PCR法研究Caspase-3 mRNA的表达情况,免疫荧光法检测Caspase-3活性。结果计算机分析表明模型组海绵体SMC含量较对照组明显减少(22.66±10.97)%vs(46.72±7.30)%,P<0.01。光镜和电镜下所见两组阴茎海绵体组织的超微结构呈显著差异。主要表现为模型组白膜结构改变,海绵体SMC明显减少,胶原成分增多。内皮细胞及SMC内存在脂质囊泡,线粒体、内质网等细胞器出现损伤,SMC凋亡小体明显增多。模型组的Caspase-3 mRNA表达和活性值均显著高于对照组mRNA:(0.77±0.01)vs(0.68±0.01),P<0.01;活性值:(0.04±0.00)vs(0.02±0.00),P<0.05。结论高脂、高胆固醇饮食可严重影响阴茎海绵体组织结构,主要表现为海绵体组织中SMC成分减少、胶原增加,使阴茎海绵体发生纤维化,这可能是高脂导致ED的重要原因之一。

Objective To compare the ultrastructure and the content of smooth muscle cell （SMC） of corpus cavernous between the hyperlipidemia-induced vasculogenic erectile dysfunction （rED） rabbits and normally feeding rabbits. Methods Eight New-Zealand white male rabbits were derided into 2 groups radomly： Group 1 was fed normal diet for 8 weeks as control. Group 2 were established as rED models by means of hypercholesterol feeding combined with ballon de-endothelialization of internal iliac arteries. Corpus cavernous tissue was then collected for light microscope and transmission electron microscope study. Caspase-3 mRNA expression and activity were invested by RT-PCR and irnmunofluorescence. Results The content of SMC in the vED cavernous decreased significantly compared with the control group（22.66±10.97）% vs （46.72±7.30）%, （P〈0.01 ）. Significant ultrastructural pathological changes were observed in the tunica albuginea and corpus cavernous tissue in the rED rabbits： The tunica albuginea degenerated and became thinner while the smooth muscle fibers were replaced by collagen fibers in the cavernous. Some endothelial cells and SMC exhibited damaged mitochondria and endoplasmic reticulums, and the apoptofic body of SMC could be seen Dnnctitformly as well.The mRNA expression and activity of Caspase-3 of the ED group was significantly higher than that of control group, mRNA expression（0.77±0.01） vs （0.68±0.01）, P〈0.01; activity value： （0.04±0.00） vs （0.02±0.00）, P〈0.05. Conclusion Hypedipidemia can affect the content of SMC and ultrastructure of the penile cavernous tissue. These pathological changes maybe involved in the process of cavernous fibrosis, which might be one of the important mechanisms of ED induced by hyperlipidimea.