Institute of Microcirculation, Hebei North University, Hebei, People's Republic of China.
Shock. 2013 Jul;40(1):49-58. doi: 10.1097/SHK.0b013e31829635cf.
The aim of this present study was to examine changes in RhoA protein levels and the role in RhoA in lymphatic contractility and reactivity after hemorrhagic shock. Levels of RhoA and phospho-RhoA in lymphatic tissue isolated from hemorrhagic shock rats were measured, and the contractility and reactivity to substance P of lymphatics isolated from control rats and rats subjected to shock 0.5 and 2 h were determined with an isolated lymphatic perfusion system at a transmural pressure of 3 cmH2O. At the same time, lymphatics isolated from rats subjected to shock 0.5 and 2 h were incubated with agonists and antagonists of RhoA/Rho kinase signaling. Contractile frequency, end-diastolic and end-systolic diameter, and passive diameter were recorded and used to calculate lymphatic tonic index, contractile amplitude, and fractional pump flow. After stimulation with a gradient of substance P, the differences between the preadministration and postadministration values of contractile frequency, contractile amplitude, tonic index, and fractional pump flow were calculated to further assess lymphatic reactivity. RhoA protein levels were significantly increased at 0.5 h after shock but decreased at 2 and 3 h after shock; p-Rho levels were initially increased after shock and subsequently decreased. The contractility and reactivity of 0.5-h-shocked lymphatics were significantly reduced by the RhoA antagonist C3 transferase and the Rho kinase antagonist Y-27632. The RhoA agonist U-46619 increased the contractility and reactivity of 2-h-shocked lymphatics, whereas Y-27632 suppressed the effect of U-46619. Okadaic acid, an inhibitor of myosin light-chain phosphatase, had no effect on the contractility of 2-h-shocked lymphatics, but improved lymphatic reactivity. These results suggest that RhoA is involved in the modulation of lymphatic pump function during hemorrhagic shock and that its effects may be mediated by Rho kinase and MLCP.
本研究旨在探讨 RhoA 蛋白水平的变化及其在失血性休克后淋巴收缩性和反应性中的作用。测量从失血性休克大鼠分离的淋巴组织中的 RhoA 和磷酸化 RhoA 水平，并使用 3cmH2O 跨壁压的离体淋巴灌注系统测定来自对照大鼠和休克 0.5 和 2 小时大鼠的淋巴管对 P 物质的收缩性和反应性。同时，用 RhoA/Rho 激酶信号转导激动剂和拮抗剂孵育休克 0.5 和 2 小时分离的淋巴管。记录收缩频率、舒张末期和收缩末期直径以及被动直径，并用于计算淋巴紧张指数、收缩幅度和分数泵流量。在 P 物质梯度刺激后，计算收缩频率、收缩幅度、紧张指数和分数泵流量的给药前和给药后差值，以进一步评估淋巴反应性。休克后 0.5 小时 RhoA 蛋白水平显著升高，但 2 小时和 3 小时后降低；休克后 p-Rho 水平先升高后降低。RhoA 拮抗剂 C3 转移酶和 Rho 激酶拮抗剂 Y-27632 显著降低了 0.5 小时休克的淋巴管的收缩性和反应性。RhoA 激动剂 U-46619 增加了 2 小时休克的淋巴管的收缩性和反应性，而 Y-27632 抑制了 U-46619 的作用。肌球蛋白轻链磷酸酶抑制剂 okadaic acid 对 2 小时休克的淋巴管的收缩性没有影响，但改善了淋巴管的反应性。这些结果表明，RhoA 参与了失血性休克期间淋巴管泵功能的调节，其作用可能通过 Rho 激酶和 MLCP 介导。
