Role of Rho kinase in blocking the return of mesenteric lymph to improve vascular calcium sensitivity in hemorrhagic shock rats

AIM: To observe the role of Rho kinase in mesenteric lymph duct ligation or mesenteric lymph drainage to improve vascular calcium sensitivity in the rats subjected to hemorrhagic shock. METHODS: Male Wistar rats were randomly divided into sham group, shock group, shock+ligation (shock plus mesenteric lymph duct ligation) group and shock+drainage (shock plus mesenteric lymph drainage) group. After induction of shock (hypotension at 40 mmHg) for 3 h, the vascular rings of superior mesenteric artery (SMA) were prepared and used to measure the response to gradient calcium ions for determining the calcium sensitivity with a wire myograph system. In shock+ligation group and shock+drainage group, the vascular rings were incubated with Rho kinase agonist angiotensinⅡ or antagonist fasudil before the measurement of the response to gradient calcium ions. RESULTS: The calcium sensitivity of vascular rings in shock group was significantly lower than that in sham group, and that in shock+ligation group and shock+drainage group was significantly higher than that in shock group, but still lower than that in sham group. AngⅡ elevated the contractile activity of the vascular rings in response to gradient calcium ions and the pD₂, and fasudil significantly decreased the response to gradient calcium ions and E_max in shock+ligation group and shock+drainage group. At the same time, fasudil decreased the pD₂ in shock+ligation group. CONCLUSION: Rho kinase plays an important role in blocking shock mesenteric lymph return that improves calcium sensitivity.