麩醯胺對於糖尿病合併敗血症小鼠發炎反應及肝臟粒線體功能之影響

高血糖會損害免疫系統，因此糖尿病患者較非糖尿病者有較高的機率罹患感染性疾病，且惡化為敗血症的相對風險也顯著增加。糖尿病與敗血症皆可能造成促發炎介質過度表現、降低粒線體氧化磷酸化反應，進而損害粒線體結構與功能，造成組織缺氧甚至器官衰竭。麩醯胺是具有免疫調節功能的條件性必需胺基酸。然而，麩醯胺對於糖尿病合併敗血症之影響尚不清楚。因此本研究之目的為探討麩醯胺介入對於糖尿病合併敗血症之發炎反應及肝臟粒線體功能之影響。雄性ICR小鼠隨機分為正常控制(normal control, NC, N=45)組、糖尿病控制(DM control, DMC, N=45)組及糖尿病-麩醯胺介入(DM glutamine, DMG, N=45)組。DMC組與DMG組小鼠以單一劑量腹腔注射每公斤體重150 mg streptozotocin誘發糖尿病，且空腹血糖值大於180 mg/dL視為誘發成功。給予NC組與DMC組餵食控制組飲食，給予DMG組餵食以麩醯胺取代25 % 酪蛋白且與控制組等氮等熱量之飼料。餵食三週後，以盲腸結紮穿刺手術(cecal ligation and puncture, CLP)誘發敗血症，並於CLP後0、6、24小時分別犧牲，取血液、腹腔沖洗液(peritoneal lavage fluid, PLF)及肝臟進行分析。與NC組相比，在CLP後6小時，DMC組顯著增加血漿alanine amionotransferase (ALT)活性以及肝臟myeloperoxidase酵素活性，但在PLF有顯著較低的interleukin-1β及monocyte chemotactic protein -1濃度。與DMC組相比，DMG組在CLP後6小時顯著降低AST及ALT活性、肝臟inducible nitric oxide synthase mRNA表現量；相較於NC組，DMG組在CLP後24小時顯著降低肝臟p65 mRNA表現量，且在CLP後6與24小時皆顯著增加肝臟peroxisome proliferator- activated receptor (PPAR)-γ mRNA表現量。在CLP後各時間點，DMC組之肝臟粒線體皆出現腫脹及嵴模糊的損傷，且隨CLP的進展而逐漸降低呼吸鏈酵素NADH-cytochrome c reductase (complexⅠ及Ⅱ)與cytochrome c oxidase (complex Ⅳ)活性。與DMC組相較，DMG組在CLP後6小時顯著增加NADH dehydrogenase subunit-1 及cytochrome c oxidase subunit Ⅰ mRNA表現量。因此，給予糖尿病合併敗血症小鼠麩醯胺的補充，可能可藉由調控p65及PPAR-γ表現量而降低促發炎介質，且減緩粒線體的損害進而維持粒線體的功能。

關鍵字

麩醯胺；糖尿病；敗血症；發炎反應；粒線體

並列摘要

Previous studies showed that patients with diabetes have greater risk of infection and tend to become sepsis easily. Diabetes or sepsis may cause overproduct of pro-inflammatory mediators, decreased mitochondrial oxidative phosphorylation (OXPHOS) and may further damage mitochondrial structure and function to lead tissue hypoxia and organ dysfunction. Glutamine (GLN) is a conditional essential amino acid with immuno-modulatory properties. However, the effects of GLN on diabetic with septic condition are not clear. This study investigated the effects of dietary glutamine on inflammatory response and hepatic mitochondrial function in diabetic septic mice. Male ICR mice were randomly assigned to normal control (NC), diabetes mellitus control (DMC) and DM with glutamine (DMG) groups. Diabetes was induced by a single dose intraperitoneal injection of 150 mg/kg body weight streptozotocin and those mice fasting blood glucose higher than 180 mg/dL were considered as diabetic mice. Mice in NC group and DMC group were fed with a common semi-purified diet and DMG group were received with a diet in which part of casein was replacing by GLN, which provided of 25 % of total amino acids. The experimental diets were isocaloric isonitrogenous and identical nutrient distributions. After feeding the respective diets for 3 weeks, septic mice were induced by cecal ligation and puncture (CLP) and were sacrificed at 0, 6, and 24 hours after CLP, respectively. The blood, peritoneal lavage fluid (PLF) and liver were collected for further analysis. The DMG group had significantly lower AST and ALT activities and inducible nitric oxide mRNA expression at 6 hours after CLP than those in the DMC group. NF-κB p65 subunit mRNA expression were significantly lower in the DMG group as compared with NC group at 24 hours after CLP, but peroxisome proliferator- activated receptor (PPAR)-γ mRNA expression was significantly higher in the DMG group than NC groups at 6 and 24 hours after CLP. Compare with DMC group, NADH dehydrogenase subunit-1 and cytochrome c oxidase subunit ⅠmRNA levels were significantly higher and the damage of hepatic mitochondrial ultrastructure was mitigated in the DMG group at 6 h after CLP. These resluts suggest that dietary supplementation with glutamine may attenuate the inflammatory mediators, modulate hepatic NF-κB and PPAR-γ level, as well as maintain hepatic mitochondrial function in diabetic mice complicated with sepsis.

並列關鍵字

glutamine ； diabetes mellitus ； sepsis ； inflammatory response ； mitochondria

參考文獻

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國際替代計量

麩醯胺對於糖尿病合併敗血症小鼠發炎反應及肝臟粒線體功能之影響

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