<Original Articles>Effect of Total Parenteral Nutrition on Liver Mitochondrial Function in Mature Rats

Abstract

To evaluate the effects of TPN on the hepatic function, the changes in hepatic energy charge levels, oxidative and phosphorylative activities of mitochondria and serum transaminase were studied, using male Sprague-Dawley rats 240 to 250 gin weight. The rats were randomized into three groups. The first group (TPN-V group, n=6) was infused with TPN solution via the right jugler vein. The number of calories of TPN solution infused daiary was adjusted to provide each rat with 80 kcal/kg/day on the 1st day, 160 kcal/kg/day on the 2nd day and 240 kcal/kg/day on the 3rd day. After the 4th day, 240 kcal/kg/day was given to both groups. The second group (TPN-G group, n=5) was infused with the same solution via an intragastric route and was given the same calories as the TPN-V group. The third group (control group, n=6) was given a chow diet with the same calories as the TPN group. At the 13th day, all groups were sacrificed, and the hepatic energy charge (EC) and phosphorylation rate (PR) of hepatic mitochondria were measured, and liver function tests were done. PR was 101. 2±5. 0 nmol/mg protein/min in control group, 120. 8±2. 7 in TNP G group and 136. 5±6. 2 in TPN-V group. EC was 0. 906±0. 006, 0. 889±0. 008, 0. 831±0. 010, respectively. The liver function tests of all group were normal. In both TPN groups, despite evidence that liver function tests were normal, enhanced michodrial phosphorylative activity was observed during the early stage of TPN. The mitochondrial enhancement in the TPN-G group was smaller than that in TPN V group. This result suggested that TPN places a load on liver mitochondria and that long term TPN may induce hepatic failure.

TPN の肝機能への影響を調べるために, 肝 Energy charge, 肝ミトコンドリア酸化的リン酸化能及び血清トランスアミラーゼ等の変化を検討した. 実験は 240 - 250 g の SD ラットを用い, 右頸静脈から高カロリー輸液を投与した群(以下 TPN-V 群, n=6), 同様の高カロリー輸液を胃痘から投与した群(以下TPN-G 群, n=5)及び上記2群と同カロリーの飼料を投与した群(以下コントロール群, n=6)の3群に分け比較検討した. 各群とも13日間 240 Kcal/kg/日のカロリーを投与した. しかし, 最初2日間は80 Kcal/kg/日(一日目), 160 Kcal/kg/日(2日目)と漸増させていき, 3日目以降に Full dose とした. 実験開始14日目に屠殺し肝を摘出, 肝ミトコンドリアを分離し肝 Energy charge, 肝ミトコンドリア機能を測定した. 結果は肝ミトコンドリア酸化的リン酸化能がコントロール群では 101. 2±5. 0 nmol/mg protein/min, TPN-G 群では120. 8±2. 7 nmol/mg protein/min, そしてTPN-V 群では136. 5±6. 2nmol/mg protein/min, であった. 一方肝 Energy charge は各々 0. 906±0. 006, 0. 889±0. 008 そして0. 831±0. 010 であった. これらの結果より TPN のカロリーの負荷が肝ミトコンドリア機能を元進させるが, 肝 Energy charge を低下させることが分かった.