AbstractsBiology & Animal Science

Burn injury is one of the most severe form of trauma and can cause an unbearable pain sensation, which is difficult to manage and has generally been treated with large doses of opioids that can cause severe side effects, such as respiratory depression. Lidocaine given intravenously (iv.) has been shown to have analgesic effect and reduce pain sensation in burn injury patients and reduced opioid requirement. The analgesic effect of iv. lidocaine is poorly understood, but lidocaine has shown extensive anti-inflammatory effects by e.g. diminishing the formation and effects of inflammatory mediators. Burn injury causes the release of a large amount of cytokines which are known to be the main regulators of the immune response and can stimulate nociception directly and indirectly. Thus, it is interesting to study the effects of lidocaine on pro- and anti-inflammatory cytokines in second degree burn injury. That might give insight into some of its analgesic properties. In addition, there is evidence that the effects might be centrally mediated as well, but that is beyond the scope of this study. In this study, blood samples were collected from anaesthetized second degree burn injured rats, receiving randomized treatment of either iv. lidocaine or saline infusion. The injury was induced by immersing the hind limbs into 80°C hot water for 10 sec. Concentration of acute pro-inflammatory (IL1β, IL-6, TNF-α, IL-8, and rCRAMP/LL-37), other pro-inflammatory (IL-2, IL-5, IFN-γ), and antiinflammatory (IL-4, IL-10, IL-13) mediators were measured in plasma. In addition, heart rate (HR) and mean arterial pressure (MAP) were recorded during the experiment. The results show a significant increase in the levels of TNF-α, IL-1β, and IL-6 (p=0.007; p=0.007; p<0.001, respectively) in plasma, 2 hours after the burn injury. However, there were no significant effects of i.v. lidocaine on cytokine levels, rCRAMP/LL-37 level, HR or MAP. Increase in the levels of acute inflammatory cytokines suggests that the burn model was effective, and can be used to study the effect of lidocaine (iv.) in second-degree burn injury in rats. However, the iv. lidocaine dose, 2.0 mg kg-1 bolus followed by 1 mg kg-1 h-1 infusion for 60 min, failed to show any significant effects on inflammatory factors or circulation. There is a possibility that the dose might be too low to induce a detectible effect, and therefore further studies are required. Sársauki af völdum bruna getur verið óbærileg upplifun, sem fer þá aðallega eftir stærð og dýpt brunasársins. Stórt annars stigs brunasár er mjög alvarlegur áverki sem er ýmsum vandkvæðum bundinn. Þörf er á að gefa stóra skammta af morfíní í æð til að lina sársaukann, sem hefur sínar aukaverkanir, m.a. öndurnarbælandi áhrif. Tilfelli hafa sýnt að lídókaín í æð getur haft kröftug sársaukadeyfandi áhrif í sjúklingum með alvarlegan annars stigs bruna og minnkaða þörf á morfíni. Ekki er vitað hvernig þessi verkjastillandi áhrif lídókaíns er framkölluð, en sýnt hefur verið fram á að lídókaín getur haft víðtæk bólgueyðandi…