The Effects of Isoflurane on the Expression of iNOS mRNA in Endotoxemic Rats / 대한마취과학회지

BACKGROUND: It has been known that alveolar macrophage exposed to bacterial lipopolysaccharide (LPS) induces a lots of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) mRNA expression. The Authors elucidated the effects of iNOS mRNA expression by inhalational anesthetics (isoflurane) on endotoxemic rats and positive pressure ventilation with and without LPS. METHODS: Fifty Sprague-Dawley rats (250 - 270 g) were anesthesized with urethane injected in the peritoneal cavity. Then the expression of iNOS mRNA in the alveolar macrophages of the rats were measured after injection of LPS, 2 hours of isoflurane (0.5 - 2.5%) anesthesia, and 2 hours of positive pressure ventilation. The activities of iNOS in macrophages were measured by analysing iNOS mRNA expression by Northern blot analysis with autoradiography using the polymerase chain reaction (PCR) method. RESULTS: The size and patterns of the iNOS mRNA band in the 0.5 - 2% isoflurane group were almost same as with the control group. The size of the iNOS mRNA band in the 2.5% isoflurane group increased more than in the control group. In the continous positive-pressure ventilation with LPS group, the iNOS mRNA band was slightly increased compared to the normal lung and the continous positive-pressure ventilation without LPS group. CONCLUSIONS: Higher concentrations of isoflurane anesthesia may evoke the expression of iNOS mRNA in a septic model. Positive pressure ventilation in sepsis may induce iNOS mRNA production.

A Study of iNOS Expression in the Alveolar and NO Concentrations in the Peritoneal Macrophage by Various Anesthetics in the Endotoxemic Rats / 대한마취과학회지

BACKGROUND: It is a well known phenomenon that alveolar and peritoneal macrophages exposed to bacterial lipopolysaccharide (LPS) induce a large output of nitric oxide (NO) and an inducible nitric oxide synthase (iNOS) m-RNA expression. The author elucidate the effects on NO production and iNOS m-RNA expression of various anesthetics, inhalational (halothane, enflurane, sevoflurane) and intravenous (ketamine, propofol), on endotoxemic rats. METHODS: To examine the production of NO in peritoneal macrophages, NO concentrations were measured from the rats following 2 hours exposure to LPS and 2 hours administration of various anesthetics, respectively. Culture supernatants were collected 24 hours after exposure to LPS and anesthetics and assayed by ELISA (Enzyme Linked Immunosorbent Assay) for production of NO. iNOS m-RNA expression was measured using PCR (Polymerase Chain Reaction) techniques and autoradiography. RESULTS: In the control group, the NO concentration was measured at 120 minutes after infusion of LPS to rats, and showed 12+/-4 micrometer. After insufullation of anesthetics to experimental animals, NO concentration increased in the halothane, enflurane, sevoflurane, propofol, and ketamine groups, 132+/-27 (P< 0.05), 49+/-19 (P< 0.05), 23+/-14 (P< 0.05), 37+/-11 (P< 0.05), and 17+/-2 micrometer respectively. The size and brightness of the iNOS m-RNA bands were large in halothane, enflurane, sevoflurane, propofol and ketamine, in order. CONCLUSIONS: Intravenous anesthetics showed more stability than inhalation anesthetics with regand to production of NO and iNOS m-RNA expression in sepsis on rats. The mechanism is not clear, but it is related to the strong stimulating effect to the airway tract in from inhalational anesthetics.

Effects of Aprotinin and Insulin on Regulation of Inducible Nitric Oxide Synthase m-RNA in the Mouse Macrophage / 대한마취과학회지

BACKGROUND: Nitric oxide (NO) has been known to have antimicrobial activity, and the increased NO production in case of sepsis may play as a physiologic defense mechanism. However the increased formation of NO by the inducible nitric oxide synthase (iNOS) has been known to be implicated in pathophysiology of a variety of disease, including circulatory and septic shock. We measured the iNOS activities of mouse macrophage after application of various drugs with lipopolysaccharide (LPS) and gamma-interferon (IFN). The purpose of this study is to evaluate the inhibiting properties of various drugs to iNOS in case of sepsis. METHOD: Thirty ICR (Institue for Cancer Research) mouse weighting 30~40 gm were anesthetized with diethyl ether, and thiogycol broth was injected into peritoneal cavity. Two days later macrophages were collected from peritoneal cavity, and incubated for 24 hours in the CO2 incubator with LPS and IFN mixture and various concentration of dexamethasone, pentoxifylline, aspirin, aprotinin, regular insulin (RI) and neutral protamine hagedorn insulin (NPH). NO concentration were calculating by measuring nitrite concentration which represent the magnitude of NO production. The activities of iNOS in macrophages were measured by analysing iNOS m-RNA expression by Northern blot analysis with autoradiography using polymerase chain reaction (PCR) method. RESULT: The basic NO concentration was 13.0 +/- 8.0 micrometer. With LPS and IFN, NO concentration was increased to 104.4 +/- 31.9 micrometer. The increase in NO production by LPS and IFN was attenuated by dexamethasone (10 (-6) M only), pentoxifylline (above 10 (-10) M), aprotinin, RI, and NPH in dose dependent manner. The addition of LPS and IFN in the culture media caused increase in the iNOS m-RNA production. The aprotinin, RI, and NPH attenuated the increase in iNOS m-RNA production by LPS and IFN. Coclusion: These results suggest that the aprotinin, RI, and NPH prevent the LPS and IFN induced increase of NO production by attenuating the iNOS activity. These properties of aprotinin and insulin may be applied to the treatment of septic shock to block the enhanced formation of NO production.