目的 观察选择性阻断cGMP依赖性蛋白激酶（PKG）对恢复内毒素（LPS）孵育的大鼠血管环收缩功能的影响。方法 取SD大鼠胸主动脉血管环，随机分为正常对照组(生理盐水)、LPS组(75 μg/mL LPS)、N-硝基精氨酸甲酯（L-NAME）组(75 μg/mL LPS+0.1 mmol/L L-NAME)和DT-2三氟醋酸盐（DT-2）组(75 μg/mL LPS+0.002 mmol/L DT-2)。在体外测定LPS孵育2、3、4 h后各组血管环在苯肾上腺素（PE）作用下收缩的浓度效应曲线、最大收缩力（Emax）和产生最大收缩力的半数有效浓度（EC50）。结果 LPS孵育后各时间点血管环的收缩浓度效应曲线与对照组比较明显降低（P<0.05）。L-NAME可以提高LPS孵育2、3、4 h时血管环的收缩功能，Emax和EC50较LPS组差异有统计学意义（P<0.05）。DT2可以显著提高LPS孵育3 h时血管环的收缩功能（P<0.01），Emax和EC50的差异具有统计学意义（P<0.01），但在2 h和4 h时，DT-2组与LPS组血管环收缩的浓度效应曲线比较差异无统计学意义（P＞0.05）。结论 选择性阻断cGMP依赖性蛋白激酶可以部分恢复LPS孵育的大鼠胸主动脉血管环的收缩功能。

Objective To investigate the effects of selective blockade of cGMP-dependent protein kinase (PKG) on contractility of vascular rings incubated with lipopolysaccharide (LPS) in rats. Methods Thoracic aortic rings of SD rats were obtained, and were randomly divided into control group, LPS group, Nω-Nitro-L-arginine methyl ester (L-NAME) group and DT-2 trifluoroacetate salt group (DT-2 group). The contraction concentration-response curve, maximal tension (Emax) and concentration required for half maximal response (EC50) of vascular rings to phenylephrine (PE) were measured in vitro at different time points (2 h, 3 h and 4 h after incubation with LPS) in each group. Results The contraction concentrationresponse curves of vascular rings after incubation with LPS for different time were significantly lower than those of control group (P<0.05). L-NAME effectively improved the contractility of vascular rings after incubation with LPS for 2 h, 3 h and 4 h, and EC50 and Emax were significantly different from those of LPS group (P<0.05). DT-2 significantly enhanced the contractility of vascular rings after incubation with LPS for 3 h (P<0.01), and EC50 and Emax were significantly different from those of LPS group (P<0.01), while there was no significant difference in contraction concentration-response curves between DT-2 group and LPS group at the time points of 2 h and 4 h （P＞0.05）. Conclusion Selective blockade of PKG can partially recover the contractility of thoracic aortic rings incubated with LPS in rats.