Effects of high methionine diet on heatstroke in rat

• Main Authors: Tzy-Shiow Wang, 王姿琇
• Other Authors: Tsai-Hsiu Yang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/43f3em

碩士 === 嘉南藥理科技大學 === 營養與保健科技研究所 === 99 === According to our previous studies, the high plasma levels of S-adenosyl- homocysteine or homocysteine, one of the high-risk factors of heatstroke, may be easy to induce heatstroke induction. However, there is less attention on the use of dietary preventive medicine in treatment of heatstroke. Purpose of this study is firstly to observe the plasma levels of S-adenosylhomocysteine and homocysteine in rats after feeding the methionine or folic acid diet. Furthermore, it would be examined the effect of treatment with high folic acid diet on the physiological and pathological changes during the heatstroke formation. Male Sprague-dawley (S.D.) rats were used in this study and divided into normal diet control group (Control) (normal diet containing 0.3% methionine and 2.1 ppm folic acid), high methionine diet group (High methionine diet; H.Met) (containing 1.5% methionine and 2.1 ppm folic acid), high folic acid diet group (High folic acid diet; H. FA) (containing 0.3% methionine and 1000 ppm folic acid), and high methionine and folic acid diet group (H.MF) (containing 1.5% methionine and 1000 ppm folic acid) for four weeks. The plasma levels of homocysteine and S-adenosylhomocysteine change in each group rats were monitored by HPLC (High-Performance Liquid Chromatography) analysis. After dietary pretreatment for four weeks, rats were exposed to ambient temperature of 43℃ to induce heatstroke. In addition, rats of the room temperature control group exposed to room temperature (24 ℃). Rats were observed their physiological and biochemical changes, plasma level of the lipid peroxidation (MDA analysis) and oxygen-radical absorbance capacity (ORAC analysis), and deoxyribonucleic acid ladder and histopathology examination in the vital organs during heatstroke induction. After pretreatment with high methionine diet for four weeks, the results show that the levels of homocysteine and S-adenosylhomocysteine in plasma were significantly higher than other groups. Rat of high methionine diet group were significantly shrunk the duration time of heatstroke induction (64±0.7 min), and values of the mean arterial pressure (MAP), heart rate (HR) and other physiological parameters were early dropped from the normal range after heatstroke formation. However, after pretreatment with high folic acid diet for four weeks in rats, the levels of homocysteine and S-adenosylhomocysteine in plasma were significantly lower than other groups, and could reverse the influence of high methionine dietary feeding on abnormal plasma biochemical levels. Meanwhile, rats of high folic acid diet group were significantly prolonged the duration time of heatstroke induction (79±1.9 min), and significantly improved the heatstroke-induced arterial hypotension, cerebral ischemia and high oxidative situation. During heatstroke induction, it showed that lipid peroxidation and deoxyribonucleic acid ladder in plasma and vital organs (brain, heart, liver and kidney) in rats of high methionine dietary feeding group were significantly higher than other groups. In contrast, rats of pretreatment with high folate diet group displayed appreciate performance in the plasma level of oxygen-radical absorbance capacity, and ameliorated the conditions of high lipid peroxidation and deoxyribonucleic acid ladder fragmentation in plasma and vital organs. This study demonstrated, when high levels of methionine diet feeding, the body did increase the generation of homocysteine and S-adenosylhomocysteine, and accelerate the generation of heatstroke is closely associated. On the contrary, dietary of high levels folic acid intake did significantly decrease concentration of S-adenosylhomocysteine and homocysteine in body. Not only significantly decrease the generation of heatstroke, but also decrease the lipid peroxidation and deoxyribonucleic acid ladder of plasma or tissue in rats. Therefore, through diet intake or supplements of folic acid may be a good strategy to diminish the heatstroke-induced damage or keep away from the heatstroke induction .