肝硬化大鼠膈肌功能改变的实验研究

目的研究肝硬化大鼠膈肌损伤的作用机制。方法SD大鼠16只被随机分成对照组(n=8)和实验组(n=8)。实验组大鼠皮下注射40?l4制备肝硬化动物模型,共成模8只。应用体外灌流大鼠膈肌条的方法,分别测量其单收缩力(Pt),最大强直张力(Po),峰值收缩时间(CT),半舒张时间(1/2RT),张力最大上升速率( dT/dtmax),张力最大下降速率(-dT/dtmax),并测量在10、20、40、60、100Hz的张力,绘制力—频率曲线,同时测定膈肌组织中SOD、SDH、NOS、Na -K -ATPase、Ca2 -Mg2 ATPase的活性及MDA含量,并观察膈肌的形态学变化。结果肝硬化大鼠膈肌Pt,Po, dT/dtmax,-dT/dtmax均低于对照组(P<0.01);CT,1/2RT高于对照组(P<0.05);给予10、20、40、60、100Hz的电压刺激膈肌时,肝硬化大鼠膈肌张力明显低于对照组(P<0.05);肝硬化大鼠膈肌组织SOD、SDH、Na -K -ATPase,Ca2 -Mg2 ATPase活性明显低于对照组(P<0.05),而MDA含量和NOS活性显著高于对照组(P<0.05);肝硬化大鼠膈肌肌纤维断裂,溶解。结论肝硬化大鼠膈肌肌纤维结构受到破坏,收缩功能下降,可能与SOD,SDH,Na -K -ATPase,Ca2 -Mg2 ATPase活性降低,NOS活性和MDA含量增高有关。

The experimental study of diaphragm function changes in cirrhotic rats

Objective To study functional changes of diaphragm in the cirrhotic rats. Methods Sixteen SD rats were randomly divided into the control group (n=8)and the experimental group (n=8). The liver cirrhosis was made by subcutaneous injection of CCl4 in the rats. The strip preparations of diaphragms were put into Kreb's solution.The contractility (Pt,CT,1/2RT, dT/dtmax,-dT/dtmax,Po) and force frequency curve were recorded and analyzed by Medlab-U/4C biological signal collecting system . The superoxide dismustase of SOD, MDA,SDH,NOS,Na -K -ATPase,Ca2 -Mg2 ATPase in the diaphragm were detected and the diaphragm structure were also observed. Results The Pt, Po, dT/dtmax, -dT/dtmax were lower(P<0.05), but the CT, 1/2RT were higher than those in the control ;Giving 10,20,40,60, 100 Hz square-wave voltage to stimulate the diaphragm, the tension of the diaphragm in!cirrhotic rats were significantly lower than those of control group (P<0.05); The superoxide dismustase of SOD , SDH, Na -K -ATPase and Ca2 -Mg2 ATPase in cirrhosis rats were significantly lower(P<0.05) and MDA, NOS were higher (P<0.05) than those in the control group; The diaphragm muscle fiber breakaged and dissolved in cirrhosis rats.Conclusion The diaphragm systolic function damage in cirrhotic rats is related to the decrease of SOD, SDH,Na -K -ATPase and Ca2 -Mg2 ATPase and to the increase of MDA and NOS activities.