Saggu Shalini, Kumar Ratan
Department of Biochemical Pharmacology, Defence Institute of Physiology and Allied Sciences (DIPAS), Lucknow Road, Timarpur, Delhi 110054, India.
Food Chem Toxicol. 2007 Dec;45(12):2426-33. doi: 10.1016/j.fct.2007.06.019. Epub 2007 Jun 23.
The present study was carried out to investigate mechanism of adaptogenic activity of seabuckthorn dry leaves aqueous lyophilized extract, administered in rats at a dose of 100 mg/kg body weight prior to cold (5 degrees C)-hypoxia (428 mmHg)-restraint (C-H-R) exposure up to fall of T(rec) 23 degrees C and recovery (T(rec) 37 degrees C) from C-H-R induced hypothermia. The effect of extract treatment was studied on key metabolic regulatory enzymes in blood, liver and muscle and tissue glycogen in rats on attaining T(rec) 23 degrees C and post stress recovery of T(rec) 37 degrees C. In control rats during C-H-R exposure on attaining T(rec) 23 degrees C there was significant decrease in enzyme activities of blood hexokinase (HK), citrate synthase (CS) and glucose-6-phosphate dehydrogenase (G-6-PD); liver CS; and in muscle glycogen, and CS and G-6-PD activities. In control rats on recovery of T(rec) 37 degrees C there was also a significant decrease in liver and muscle glycogen levels along with decreased enzyme activities of blood G-6-PD; liver CS; and liver and muscle G-6-PD. This suggested that during severe stressful exposure to C-H-R and post stress recovery the aerobic metabolism as well as hexose monophosphate (HMP) pathway is suppressed. The single and five doses extract treatment restricted the decrease or better maintained tissue glycogen and enzyme activities, viz. HK, phosphofructokinase (PFK), CS and G-6-PD, in blood, liver and muscle, during C-H-R exposure (T(rec) 23 degrees C) and recovery of T(rec) 37 degrees C. The results suggest that seabuckthorn extract treatment caused a trend for shifting anaerobic metabolism to aerobic during C-H-R exposure and post stress recovery.
本研究旨在探讨沙棘干叶水冻干提取物的适应原活性机制。在大鼠暴露于寒冷（5摄氏度）-缺氧（428毫米汞柱）-束缚（C-H-R）环境直至直肠温度（T(rec)）降至23摄氏度并从C-H-R诱导的体温过低恢复至（T(rec) 37摄氏度）之前，以100毫克/千克体重的剂量给大鼠灌胃该提取物。研究了提取物处理对大鼠在达到T(rec) 23摄氏度以及应激后恢复至T(rec) 37摄氏度时血液、肝脏和肌肉中的关键代谢调节酶以及组织糖原的影响。在对照大鼠中，在C-H-R暴露期间达到T(rec) 23摄氏度时，血液己糖激酶（HK）、柠檬酸合酶（CS）和葡萄糖-6-磷酸脱氢酶（G-6-PD）的酶活性显著降低；肝脏CS活性降低；肌肉糖原以及CS和G-6-PD活性降低。在对照大鼠恢复至T(rec) 37摄氏度时，肝脏和肌肉糖原水平也显著降低，同时血液G-6-PD、肝脏CS以及肝脏和肌肉G-6-PD的酶活性降低。这表明在严重应激暴露于C-H-R期间以及应激后恢复过程中，有氧代谢以及磷酸己糖（HMP）途径受到抑制。单次和五次剂量的提取物处理限制了组织糖原和酶活性的降低，即在C-H-R暴露（T(rec) 23摄氏度）期间以及恢复至T(rec) 37摄氏度时，血液、肝脏和肌肉中的HK、磷酸果糖激酶（PFK）、CS和G-6-PD活性得到更好的维持。结果表明，沙棘提取物处理在C-H-R暴露期间以及应激后恢复过程中导致了从无氧代谢向有氧代谢转变的趋势。
