Jasson Chiang

Honokiol protects rats against eccentric exercise-induced skeletal muscle damage by inhibiting NF-κB induced oxidative stress and inflammation

Honokiol, a bioactive component isolated from the Chinese herb Magnolia officinalis, is known for its potent antioxidative and anti-inflammatory effects. To study whether honokiol can protect skeletal muscle from sports injuries, we set up an eccentric exercise bout protocol for rats consisting of downhill running on a treadmill and examined the effect of oral administration of honokiol at 1 h before eccentric exercise at a dose of 5 mg/kg on day 1 (HK5 x 1) or 1 mg/kg/day for 5 consecutive days (HK1 x 5). Eccentric exercise was implemented for 3-5 consecutive days, and induced remarkable tissue damage. This damage was associated with an increase in serum creatine levels, increase in protein nitrotyrosylation, poly-ADP-ribose-polymerase (PARP) upregulation, lipid peroxidation, and leukocyte infiltration. The degree of muscle damage also paralleled dramatic gene expression for cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and inflammation-associated cytokines (interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha, and monocyte chemoattractant protein-1), possibly through activation of nuclear factor kappa-B (NF-kappaB), a crucial proinflammatory transcription factor. Both honokiol treatments (HK5 x 1 and HK1 x 5) significantly ameliorated eccentric exercise-induced muscle damage as revealed by suppression of cell fragmentation, protein nitrotyrosylation and PARP upregulation, as well as reductions in lipid peroxidation and leukocyte infiltration, possibly through downregulating gene expression for COX-2, iNOS, and the proinflammatory cytokines by modulation of NF-kappaB activation. In conclusion, the present study demonstrates for the first time that honokiol exhibits protective effects against eccentric exercise-induced skeletal muscle damage in rats, probably by modulating inflammation-mediated damage to muscle cells.

Tai Chi Chuan Increases Circulating Myeloid Dendritic Cells

Dendritic cells, the most potent antigen-presenting cells linking innate and adoptive immunity, are thought to be important targets of immune modulators such as exercise. We examined the effect of Tai Chi Chuan (TCC) on dendritic cells. TCC practitioners were further divided to high-level practitioners (TCC-H) and low-level practitioners (TCC-L). The quantities of myeloid and plasmacytoid dendritic cells were estimated by flow cytometry. We examined parameters including age, body weight, body length, body fat, and serum albumin level, in the controls, TCC-H and TCC-L, which did not differ significantly. The mean peak (volume of O2 utilization) of the TCC-H group was greater than that of the sedentary control group. White blood cell (WBC) count in the entire TCC group was greater than that of the controls. The quantity of myeloid dendritic cells was significantly greater in the TCC group, whereas the quantity of plasmacytoid dendritic cells was similar for both groups. Among the TCC subgroups, the quantity of myeloid dendritic cells, but not plasmacytoid dendritic cells, in the TCC-H group was greater than that of TCC-L practitioners. TCC could increase the number of circulating myeloid dendritic cells, but not plasmacytoid dendritic cells, in a performance level-dependent manner.

The Design of Dual-Axis Load Cell for Measuring Force Load in Kayak Paddling

The purpose of this study was to design a dual-axis load cell that is suitable for measuring force load in kayak paddling. We used Finite Element Method (FEM) to analyze the change in stain profile of the dual axis load cell under different loading condition by alternating different strain gage placements for measuring the effects on coupled force and maximum strain output for determining the optimal placement sites of strain gage for designing the dual-axis load cell. The results of this study indicated that the size and placement sites were suitable for measuring force load in kayak paddling.