title: Effect of HX108-CS supplementation on exercise capacity and lactate accumulation after high-intensity exercise.
abstract: BACKGROUND
  In the present study, we determined the effects of HX108-CS (mixed extract of Schisandra chinensis and Chaenomeles sinensis) supplementation on lactate accumulation and endurance capacity. Furthermore, we examined CK (creatine kinase), LDH (lactate dehydrogenase) activity to determine whether the HX108-CS affected markers of skeletal muscle injury in vivo and in vitro.
  
  
  METHODS
  Exercise capacity was measured by an exhaustive swimming test using ICR mice divided into four groups; one group received distilled water (DW) (Control group, n = 10), and the other groups received three different dosages of HX108-CS (10, 50 and 100 mg/kg, n = 10 per group) solution in water orally. Then, for the time-dependent measurements of blood lactate, CK, and LDH, Sprague-Dawley rats were divided into two groups; one received DW (Control group, n = 10), and the other group received HX108-CS (100 mg/kg, n = 10) solution in the same way as mice. Before the exercise test, the animals were given either DW or HX108-CS for 2 weeks. High-intensity treadmill exercise was performed for 30 minutes. Blood samples were collected and analyzed during and after exercise. For the in vitro experiment, C2C12 cells were treated with HX108-CS to examine its effect on lactate production, CK, and LDH activity.
  
  
  RESULTS
  Blood lactate concentration was significantly lowered immediately after treadmill exercise in HX108-CS group; however, there were no significant differences in activities of CK and LDH between HX108-CS and control during treadmill exercise and recovery phase. Furthermore, treatment with 100 mg/kg of HX108-CS led to a significant increase in the time to exhaustion in swimming test, and concurrently blood lactate concentration was significantly decreased in 50 and 100 mg/kg treated group. Moreover, our results of in vitro experiment showed that HX108-CS suppressed lactate production, CK, and LDH activity in a dose-dependent manner.
  
  
  CONCLUSIONS
  These results suggest that supplementation with HX108-CS may enhance exercise capacity by lowering lactate accumulation. This may in part be related to an amelioration of skeletal muscle injury.
authors.affiliation: Health and Exercise Science Laboratory, Institute of Sports Science, Seoul National University, 599 Gwanang-no, Gwanak-gu, Seoul, 151-742, Korea. songw3@snu.ac.kr.
authors.forename: Seung-Lyul
authors.initials: SL
authors.lastname: Oh
authors.forename: Hyukki
authors.initials: H
authors.lastname: Chang
authors.forename: Hee-Jae
authors.initials: HJ
authors.lastname: Kim
authors.forename: Yong-An
authors.initials: YA
authors.lastname: Kim
authors.forename: Dong-Sik
authors.initials: DS
authors.lastname: Kim
authors.forename: Seong-Hyun
authors.initials: SH
authors.lastname: Ho
authors.forename: Seon-Hee
authors.initials: SH
authors.lastname: Kim
authors.forename: Wook
authors.initials: W
authors.lastname: Song