失血性休克大鼠淋巴管对去甲肾上腺素反应性的变化

目的:观察失血性休克(HS)大鼠淋巴管对去甲肾上腺素(NE)反应性的变化,探讨淋巴管反应性在休克发病学中的作用。方法:假手术组(sham)和失血性休克组(HS,股动脉放血使血压维持40mmHg)各8只大鼠行胸导管腹段插管,测压,观察在不同时点股静脉注射NE(5μg/kg)前后淋巴管压力的变化;通过微循环录像系统对每组另8只大鼠回肠下段肠系膜淋巴管(ML)活体标本的自主收缩频率(F)、最大收缩口径(a)、最大舒张口径(b)、静态口径(c)连续记录,计算不同时点给予NE前后淋巴管收缩分数(index I)、总收缩活性指数(indexⅡ)、淋巴管动力学指数(LD-index)的变化(用△表示)。结果:HS组自休克30min起对NE的升压反应开始减弱,呈进行性降低,1h-3h间各时点的升压幅度显著低于sham组。HS组ML在休克1h的△F、△indexⅡ、△LD-index以及1.5h、2.h的△F、△index I、△indexⅡ、△LD-index均显著低于sham组,且在这3个时点的△F、△index I、△indexⅡ、△LD-index均显著低于休克前。结论:大鼠淋巴管的反应性在失血性休克发展进程中呈进行性下降,淋巴管低反应性在休克发病学中可能具有重要作用。

Changes of lymphatic vessel response to norepinephrine in hemorrhagic shock rats

AIM: To observe the changes of lymphatic vessel response to norepinephrine (NE) in hemorrhagic shock (HS) rats, and to explore the role of lymphatic reactivity in the pathogenesis of shock. METHODS: The lymphatic vessel pressure was observed through intubating into abdomen thoracic duct in 8 rats in sham group and HS group (which was bled from femoral artery until the mean arterial pressure to 40 mmHg). The changes of lymphatic vessel pressure response to NE at different time points were observed by injection of NE (5 μg/kg) through femoral vein. The spontaneous contraction frequency (F), maximal contraction diameter (a), maximal diastolic diameter (b) and static diameter (c) of mesenteric lymphatic (ML) living samples in 8 rats of each group were recorded through microcirculation video systems continuously. The changes of lymphatic fractional contraction index (index I), total contractile activity index (index II) and lymphatic dynamic index (LD-index) (to show the value using △F, △index I, △indexⅡ, △LD-index) were calculated after injection of NE at different time points. RESULTS: The changes of lymphatic boosting pressure response to NE in HS group was started to diminish 30 min after shock, and showed a progressive decreasing trend which significantly reduced than that in sham group at all time points of shock 1 h-3 h. In HS group, the △F, △indexⅡ, △LD-index at shock 1 h, the △F, △index I, △indexⅡ, △LD-index at shock 1.5 h and 2 h were significantly lower than those in sham group, and the △F, △index I, △indexⅡ, △LD-index at all time points were significantly decreased as compared to the values of pre-shock. CONCLUSION: Lymphatic vessel reactivity in shock rats is progressive declined in the process of hemorrhagic shock. The lymphatic vessel hypo-reactivity might play an important role in the pathogenesis of shock.