Early adverse changes in liver microvascular circulation during experimental septic shock are not linked to an absolute nitric oxide deficit

• Nitric oxide and microcirculatory parameters were simultaneously assessed in the liver.
• Hepatic microcirculation impairment was evident in the early phase of sepsis.
• No absolute NO deficit was seen, despite the adverse changes in the microcirculation.
• These data rule out any direct involvement of NO deficit in early microcirculatory disturbances.

Nitric oxide (NO) is believed to play a key role in adverse microvascular changes during sepsis. A deficit in NO has been evoked as a potential mechanism of microcirculatory deterioration in the early phase of septic shock. The aim of this study was to evaluate simultaneously and continuously both hepatic microcirculation and local NO production during early experimental sepsis.Wistar male rats were divided into two groups: a sepsis group undergoing cecal ligation and puncture (CLP) peritonitis and a control group undergoing sham surgery. Hepatic microcirculation was continuously monitored using a laser Doppler probe and local nitric oxide (NO) production by means of a specific electrode. Constitutive and inducible NO synthase production was assessed 2 h after surgery, at onset of shock, and at 2 and 3 h after shock.In control animals, hepatic microcirculatory perfusion and NO production remained stable throughout the experiment. In septic animals, whereas a fall in microcirculatory perfusion was noted as early as 2 h after CLP, NO concentration remained stable and further increased after the onset of shock. At this time, inducible NO synthase was the only isoform significantly elevated.In this non-resuscitated experimental model of sepsis, an absolute liver deficit of NO could not explain the early adverse changes in the local microvascular system.