Acute effects of guanosine or inosine in a porcine model of hemorrhagic shock.

Hemorrhagic shock (HS) leads to systemic hypoperfusion, impaired tissue oxygenation, and multi-organ dysfunction, including central nervous system (CNS) injury. Guanosine and inosine, purine nucleosides with neuroprotective and anti-inflammatory properties, have demonstrated beneficial effects in models of neurotoxicity, ischemia, and septic shock. This study evaluated the acute effects of guanosine and inosine in fluid resuscitation, focusing on brain energy metabolism, neuroinflammatory mechanisms, and hemodynamic responses in a porcine model of HS. Thirty pigs (25-30 kg) underwent controlled hemorrhage to achieve a target mean arterial pressure (MAP) of 40 - 45 mmHg, maintained for 60 min. Animals were randomized into three resuscitation groups: Lactated Ringer's solution (LR), LR + guanosine (1 mmol/L), and LR + inosine (1 mmol/L), administered over 15 - 20 min. Hemodynamic, metabolic, and neuronal parameters were monitored for 440 min post-HS, with serial blood and cerebrospinal fluid (CSF) sampling to assess glutamate, lactate, glucose, neuron-specific enolase (NSE), and inflammatory cytokines. HS induced metabolic acidosis, increased CSF glutamate levels, and elevated proinflammatory cytokines (IL-1β, TNF-α, IFN-γ, IL-8). Guanosine and inosine reduced glutamate levels more rapidly than LR alone and attenuated IL-1β and TNF-α elevations. Inosine resuscitation improved MAP, systemic vascular resistance index (SVRI), and end-diastolic volume index (EDVI), suggesting enhanced hemodynamic stabilization. Guanosine and inosine modulated neuroinflammatory and metabolic responses in HS, reducing excitotoxicity and inflammatory cytokine release. Inosine also demonstrated hemodynamic benefits. These findings support further investigation into their therapeutic potential in shock resuscitation.