ABSTRACT
BACKGROUND: Hemorrhagic shock (HS) results in oxidative stress to cells and in the induction of the inflammatory response, with an increased expression of a number of proinflammatory mediators and cytokines. We tested the ability of the nitric oxide (NO) donor sodium nitroprusside (NP) to reduce tissue injury in a rodent model of uncontrolled hemorrhagic shock. METHODS: Seventy two Sprague Dawley rats weighing 250-300 g were subjected to a model of uncontrolled hemorrhagic shock. Four groups of animals were included (n = 18 per group): sham/saline, sham/NP, shock/saline, shock/NP. Experimental design consisted of the development of hemorrhagic shock (3 ml/100 g) in a 15-min period, tail amputation (75%) and drug administration at 30 min, fluid resuscitation (FR) with Ringer's lactate (RL) solution to reach a mean arterial pressure (MAP) of 40 mmHg, a hospital phase of 60 min with hemostasis and FR with LR solution to reach a MAP of 70 mmHg, and a 3-day observation phase. Treatment at the beginning of resuscitation included either normal saline (groups 1, 3) or NP (0.5 mg/kg) (groups 2, 4). The following parameters were evaluated: fluid requirements for resuscitation, liver injury tests, liver tissue myeloperoxidase (MPO), liver histology, and 3-day survival. RESULTS: NP significantly reduced fluid requirements for resuscitation (p = 0.0001). We also observed an improved statistically significant difference in tests demonstrating hepatic injury (p = 0.0001), neutrophil infiltration as evidences by liver MPO (p <0.05), and histology studies (p = 0.001). Survival was also increased from 40% in controls to 60% with NP treatment. CONCLUSIONS: These data suggest that excess NO mediates hemorrhage-induced liver injury, and that the suppression of NO with NP may reduce the pathological consequences of severe hemorrhage, possibly by scavenging superoxide (O(2)(-)), thus limiting the production of more aggressive radicals.
Subject(s)
Animals , Male , Rats , Shock, Hemorrhagic/drug therapy , Liver Circulation/drug effects , Nitric Oxide Donors/therapeutic use , Hepatitis/prevention & control , Nitroprusside/therapeutic use , Reperfusion Injury/prevention & control , Drug Evaluation, Preclinical , Nitric Oxide Donors/pharmacology , Reactive Oxygen Species/metabolism , Oxidative Stress/drug effects , Fluid Therapy , Hepatitis , Isotonic Solutions , Liver , Models, Biological , Necrosis , Nitroprusside/pharmacology , Nitric Oxide/physiology , Peroxidase/analysis , Rats, Sprague-Dawley , Reperfusion Injury , Resuscitation , Shock, Hemorrhagic , Single-Blind MethodABSTRACT
En este trabajo se ha desarrollado una metódica simple que ha permitido la obtención de catepsina D de próstata humana en cantidades apreciables para estudios enzimáticos y químicos, empleando cromatografías combinadas de intercambio en DEAE celulosa y cromatoenfoque en gel PBE-94. La síntesis química de un nuevo sustrato sintético permitió comparar la actividad hidrolítica de la catepsina D con las gastricsinas de próstata y líquido seminal humano, así como con pepsina y gastricsina de mucosa gástrica. La actividad de la catepsina prostática sobre el sustrato sintético N-acetil-L-fenilalanil-L-diyodotirosil-L-valina metil éster (APDTV) fué similar a la de las gastricsinas y mucho mayor con respecto a la pepsina. Las relaciones ácido glutámico/ácido aspártico (Glu/Asp) y leucina/isoleucina (Leu/Ile) de la catepsina D son semejantes a las presentes en las gastricsinas y no en las pepsinas, en cuyo caso estos aminoácidos se encuentran en una razón inversa