|摘要: ||左旋精胺酸(L-Arginine；L-Arg)是一種天然胺基酸，其在體內參與許多重要的生化反應，例如其可在腎臟被代謝為一氧化氮(NO)或多胺類物質(polyamine)，啟動特定的生理反應；L-Arg的生理功能，也大多與血液及組織中NO的濃度有關；在人體內NO為非常重要的細胞訊息分子（cellular signaling molecule）；一些研究發現額外補充L-Arg可以降低激烈運動後衰老大鼠體內的氧化壓力；然而在超氧陰離子(superoxide anion，O2-)存在下，NO將被快速的轉換成活性氮分子（Reactive Nitrogen Species；RNS），而造成氧化壓力，故本實驗目的為瞭解L-Arg對於大鼠體內氧化壓力、抗氧化酵素系統、脂肪代謝及肝功能的影響，並探討L-Arg產生的NO或氧化壓力對於大鼠精子品質(精子數目、型態及尾部泳動率)之影響。我們利用24隻十週大Sprague-Dawley(SD)雄性大鼠並隨機分為三組(n=8)，(1)Control組-C組(2) L-Arginine組-L組(3) L-Arginine+Vitamin E組-LE組，並採用AIN-93G飲食配方，飼料及飲水採自由進食。在飼養30天後，以CO2將其犧牲；並進行樣品分析。結果發現L組大鼠肝臟、腎臟的NO濃度較C組增加23%與51%；LE組大鼠肝臟、腎臟的NO濃度較C組增加19%與51%；而添加L-Arg的組別其血清中TC、TG及LDL-C均比C組明顯下降19%、30.4%、37%；添加L-Arg+Vit E的組別其血清中TC、TG及LDL-C均比C組明顯下降16%、28%、24%；NO濃度上升亦增加肝臟GPx及CAT活性使肝臟TBARS濃度明顯低於C組(L組：26%，LE組：25%)；至於腎臟中的NO濃度上升使得其SOD、GPx及CAT活性下降；L組大鼠腎臟TBRAS濃度明顯高於C組與LE組；睪丸各組間則無明顯差異；血清中GOT與GPT各組間均無顯著差異；而在精子數量及擺動率方面：添加L-Arg及L-Arg+Vit E的組別其精子活動力均明顯較C組高出41%與40%；在精子型態上，三組間精子的外觀並無顯著性差異；L組與LE組大鼠精子的ROS含量與C組比較後，分別增加了91%與95%，精子數目也顯著增加且泳動率也受到影響。根據研究結果表明，額外補充2% L-Arg可增加大鼠體內NO的含量，然而也調節脂質代謝、氧化壓力、抗氧化酵素活性、增加精子數目及泳動率；而多補充L-Arg的大鼠因體內NO所產生的ROS而增加其精子獲能的機會；但補充L-Arg並不影響老鼠體重增加率、飲食習慣、肝損傷。
關鍵字：L-Arginine、Anti-oxidant Enzyme System、TBARS、Sperm
L-arginine (L-Arg) is a naturally occurring amino acids involved in many important biochemical reactions in mammalian tissues. The physiological functions of L-Arg , are strongly related to the nitric oxide (NO) concentration in the blood or tissues. NO is a very important cell signaling molecular which is produced from L-Arg by NO synthase. Although , some studies have shown that the additional supplement of L-arg can reduce the oxidative stress in aging rats with acute exercise. However, in the presence of Superoxide anion (O2-), NO will be quickly converted to reactive nitrogen molecules (RNS) causing oxidative stress. Therefore , the aim of this study was to investigate the effects of L-Arg on the NO generation,oxidative stress,antioxidant enzyme systems,lipid metabolism and liver function in the rat. Moreover, the influences of L-Arg (NO) on the sperm quality (sperm number,morphology and mobility) in rat were also studied in this study. Twenty-four male Sprague-Dawley (SD) rats (10-week-old) were randomly divided into three groups (n = 8), (1) Control group (C group) (2) 2% L-arginine group (L group) (3) 2% L-arginine + Vitamin E group (LE group). The rats were fed an AIN-93G diets with or without 2% L-Arg and Vit E. After 30 days,the animal were sacrificed and sample were analyzed. The concentration of NO in the Liver and kidney of rats in L and LE group increased significantly from 19% to 51% when compared with the rat in C group. The concentration of TC,TGand LDL-C in the plasma of the rats in L and LE group were decreased significantly from 16% to 36% when compared with the rat in C group. The activities of Catalase (CAT) and Glutathione Peroxidase (GPx) in the rat’s liver (L and LE group) were regulated by NO,thus,the TBARS concentration in rat liver were significant lower than the rats in C group. Whereas,opposite effect was observed in kidney of rats in L and LE group. The rat’s sperm number were significant increased in L (41%) and LE groups(40%) when compared with the rat in C group. The amount of Reactive Oxygen Species (ROS) in the sperm of rats in L (91%) and LE groups (95%) were also significant increased when compared with the rat in C group. Thus,the sperm mobilities of rats in experiment groups were affected. The results from this studies indicates additional supplement of 2%L-Arg may increase the NO production in rats. NO then regulated the lipid metabolism,oxidative stress,antioxidative enzyme activities and spermatogenesis in rats. Moreover,the ROS generated from NO in the sperm of rats fed L-Arg caused the capacitation of sperm.
Keywords: L-Arginine、Anti-oxidant Enzyme System、TBARS、Sperm