活体墨汁灌注显示的雌性犬尿道黏膜下血管结构的形态学特征

Morphological Features of Urethral Submucosal Vascular Plexus in Female Canines Demonstrated by Ink Perfusion in vivo

目的采用活体墨汁灌注法显示和观察雌性犬尿道黏膜下血管结构的形态和分布特征。方法采用6只健康成年雌性中华田园犬,年龄2岁,体重(8.5±0.6)kg。腹腔麻醉下显露尿道、膀胱、腹主动脉、下腔静脉。行膀胱造瘘并半充盈膀胱,行腹主动脉穿刺并灌注墨汁-右旋糖酐混合液,活体状态下观察尿道和膀胱被墨汁充盈和染色的过程。血管充分灌注后过量麻醉处死动物,整块取出尿道、膀胱、阴道及周围组织,固定后分块包埋并连续冰冻切片。体视显微镜下观察尿道及膀胱壁内血管形态,采用Image J软件测量和比较不同部位组织内的血管密度。结果在动物存活状态下行墨汁灌注,膀胱及尿道不同节段着色深浅不同,远段、次远段和中段尿道着色较深,近段着色较浅,膀胱着色最深。镜下观察发现,尿道及膀胱壁内血管结构清晰可见,无墨汁溢出血管。尿道不同节段和不同方位及膀胱壁内血管结构形态学特征如下:远段尿道壁内可见大面积均匀分布的海绵状血管窦;次远段尿道前壁内可见密集的大囊状血管窦,尿道后壁内的血管窦明显较小;中段尿道壁内均可见大囊状血管窦,仍以前壁为主;近段尿道壁内囊状血管窦逐步缩小,几无极性分布现象;膀胱壁内血管多呈细网状,无极性分布现象。相较于远段、中段和近段尿道,次远段尿道黏膜下血管丛的血管密度最大(P<0.01),远段、次远段和中段尿道前壁内的血管密度均显著高于后壁的血管密度(P<0.01),近段尿道前壁与后壁内血管密度的差异无统计学意义(P>0.05)。结论活体墨汁灌注法是显示尿道壁内血管结构的有效方法,该研究首次获得了雌性犬在存活状态下血管灌注墨汁后所显示的尿道壁内微血管结构的形态和分布特征,为进一步探索尿道壁内血管与控尿机制之间的关联提供了实验基础。

Objective To study the morphology and distribution features of urethral submucosal vascular plexus in female canine demonstrated by ink-perfusion in vivo.Methods Totally 6 healthy female canines were used for this study,aged 2 years and weighed(8.5±0.6)kg.Under intraperitoneal anesthesia,a midline abdominal incision was made and the urethra,bladder,abdominal aorta and inferior vena cava were exposed.Cystectomy was made and the bladder was half-filled with saline.Abdominal aorta puncture was performed and ink-dextran solution was perfused in vivo.When the urethra,bladder,skin and finally the whole body gradually became dark,the abdominal aorta and inferior cava were ligated.The animals were sacrificed by overdose anesthesia.Then the bladder,urethra,vagina and surrounding tissues were harvested and were fixed.Tissue blocks were embedded and serial frozen sections were prepared.The urethra and its submucosal vascular plexus were observed under stereoscopic microscope.Submucosal vascular density of the urethra was measured by the Image J software.Results Gross observation showed that the different segments of urethra and bladder were stained differently in vivo.The distal,sub-distal and middle urethral segments were darker than the proximal urethral segment,while the bladder was the deepest in dark.Under the stereomicroscope,the microvascular structure of urethra and bladder wall was clearly visible.The morphological characteristics of vascular plexus in different segments and different zones of urethral submucosa and bladder wall were as follows.There was large area of cavernous vascular sinusoids distributed uniformly in the submucosa of distal urethral segment.And large size cystic vascular sinusoids were observed in sub-distal urethral segment and middle urethral segment,mainly in anterior urethral wall.The size of vascular sinusoid became smaller in the proximal urethral wall and almost without polarized distribution.The vessels in the bladder wall were mostly thin and reticular,with no polarized distribution.Compared with the distal,middle and proximal urethra,the vascular density in subdistal urethral submucosa was the highest.The vascular density in the anterior wall of distal,subdistal and middle urethral submucosa was significantly higher than that in the posterior wall,but there was no significant difference between the anterior and posterior wall of proximal urethral submucosa.Conclusion Ink perfusion in vivo is proved being an effective method for visualizing the submucosal microvascular structure of the urethra.The morphology and distribution characteristics of the urethral submucosal microvascular structure in female canines were obtained for the first time,which provides a basis for further exploration of the relationship between the urethral submucosal vascular structure and urinary continence.