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Abstract
BackgroundReactive oxygen species (ROS) and reactive nitrogen species (RNS) are produced during hemorrhagic shock and resuscitation (H/R), which may contribute to multiple organ failure. The Aim of this study was to test the hypothesis that green tea (Camellia sinenesis) extract containing 85% polyphenols decreases injury after H/R in rats by scavenging ROS and RNS.MethodsFemale Sprague Dawley rats were given 100 mg polyphenol extract/kg body weight or vehicle 2 h prior to hemorrhagic shock. H/R was induced by two protocols: 1) withdrawal of blood to a mean arterial pressure of 40 mm Hg followed by further withdrawals to decrease blood pressure progressively to 28 mm Hg over 1 h (severe), and 2) withdrawal of blood to a sustained hypotension of 40 mm Hg for 1 h (moderate). Rats were then resuscitated over 1 h with 60% of the shed blood volume plus twice the shed blood volume of lactated Ringer's solution. Serum samples were collected at 10 min and 2 h after resuscitation. At 2 or 18 h, livers were harvested for cytokine and 3-nitrotyrosine quantification, immunohistochemical detection of 4-hydroxynonenol (4-HNE) and inducible nitric oxide synthase (iNOS) protein expression.ResultsAfter severe H/R, 18-h survival increased from 20% after vehicle to 70% after polyphenols (p < 0.05). After moderate H/R, survival was greater (80%) and not different between vehicle and polyphenols. In moderate H/R, serum alanine aminotransferase (ALT) increased at 10 min and 2 h postresuscitation to 345 and 545 IU/L, respectively. Polyphenol treatment blunted this increase to 153 and 252 IU/L at 10 min and 2 h (p < 0.01). Polyphenols also blunted increases in liver homogenates of TNFα (7.0 pg/mg with vehicle vs. 4.9 pg/mg with polyphenols, p < 0.05), IL-1β (0.80 vs. 0.37 pg/mg, p < 0.05), IL-6 (6.9 vs. 5.1 pg/mg, p < 0.05) and nitrotyrosine (1.9 pg/mg vs. 0.6 pg/mg, p < 0.05) measured 18 h after H/R. Hepatic 4-HNE immunostaining indicative of lipid peroxidation also decreased from 4.8% after vehicle to 1.5% after polyphenols (p < 0.05). By contrast, polyphenols did not block increased iNOS expression at 2 h after H/R.ConclusionPolyphenols decrease ROS/RNS formation and are beneficial after hemorrhagic shock and resuscitation.
Highlights
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are produced during hemorrhagic shock and resuscitation (H/R), which may contribute to multiple organ failure
Polyphenol treatment did not change the amount of hemorrhage required to cause hypotension, since bleed out volume in the polyphenol-treated group was 19.4 ± 1.5 ml/kg body weight versus 21.3 ± 1.1 ml/kg body weight in the water gavage group (Table 1, p > 0.2)
Blood pressure was comparable between the polyphenol-treated and untreated hemorrhaged groups before, during and after shock (Table 1)
Summary
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are produced during hemorrhagic shock and resuscitation (H/R), which may contribute to multiple organ failure. Patients that initially survive hemorrhage and resuscitation (H/R) may develop a systemic inflammatory response syndrome (SIRS) that leads to injury and dysfunction of vital organs (multiple organ dysfunction syndrome, MODS) [1]. Systemic hypotension with resuscitation leads to complex alterations in local tissue perfusion, hypoxia and generation of reactive oxygen and nitrogen species (ROS and RNS). ROS and RNS trigger release of cytokines and chemokines, leading to surface expression of adhesion molecules and leukocyte infiltration. These events produce inflammation, tissue damage and multiple organ failure [4,5,6]. Antioxidant strategies blunt SIRS, and numerous animal studies highlight the association of a variety of inflammatory mediators with organ damage after H/R [9,10,11,12,13]
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