Effect of ginsenoside Rb1 on neurotrophic factors in elderly rats with postoperative fatigue syndrome Improvement of ginsenoside Rb1 on inflammation of central nervous system in postoperative fatigue syndrome rats Study on characteristics of energy metabolism in skeletal muscle of rats with postoperative fatigue syndrome and interventional effect of ginsenoside Rb1 Effect of ginsenoside Rb1 on central oxidative stress of rats with postoperative fatigue syndrome