Anti-inflammatory Effects of Sanguisorbae Radix on Contact Dermatitis Induced by Dinitrofluorobenzene in Mice / 中国结合医学杂志

OBJECTIVE@#To investigate the anti-inflflammatory effects of Sanguisorbae Radix on contact dermatitis (CD).@*METHODS@#Mice were sensitized by painting 30 µL of 1-fluoro-2,4-dinitrofluorobenzene (DNFB) onto each ear for 3 days. Four days later, mice were challenged by painting with 50 µL of DNFB onto the shaved dorsum every 2 days. Sanguisorbae Radix methanol extract (MESR) was applied onto the shaved dorsum every 2 days. The effects of MESR on skin thickness, skin weights, histopathological changes, skin lesions and cytokine production in DNFB-induced CD mice were investigated, as well as its effects on body weights and spleen/body weight ratio.@*RESULTS@#Topical application of MESR effectively inhibited enlargement of skin thickness and weight (P<0.05). MESR treatment also inhibited hyperplasia, spongiosis and immune cell infiltration induced by DNFB in inflamed tissues and improved lesions on dorsum skin in CD mice. Moreover, treatment with MESR suppressed the increase in the levels of tumor necrosis factor α (TNF-α,P<0.01) and interferon γ (IFN-γ,P<0.05), respectively. Finally, MESR had no effect on body weight gain or spleen/body weight ratio.@*CONCLUSION@#These data suggest that MESR acts as an anti-inflflammatory agent that decreases the production of TNF-α and IFN-γ, resulting in reductions of skin lesions and histopathological changes in inflamed skin tissues.

Sasa borealis extract exerts an antidiabetic effect via activation of the AMP-activated protein kinase

Leaf of Sasa borealis, a species of bamboo, has been reported to exhibit anti-hyperglycemic effect. However, its antidiabetic mechanism is not fully understood. In this study, we examined whether an extract of S. borealis activates AMP-activated protein kinase (AMPK) and exerts anti-hyperglycemic effects. Treatment with the S. borealis extract increased insulin signaling and phosphorylation of AMPK and stimulated the expression of its downstream targets, including PPARalpha, ACO, and CPT-1 in C2C12 cells and PPARalpha in HepG2 cells. However, inhibition of AMPK activation attenuated insulin signaling and prevented the stimulation of AMPK target genes. The S. borealis extract increased glucose uptake in C2C12 cells and suppressed expression of the gluconeogenic gene, PEPCK in HepG2 cells. The extract significantly reduced blood glucose and triglyceride levels in STZ-induced diabetic mice. The extract enhanced AMPK phosphorylation and increased Glut-4 expression in the skeletal muscle of the mice. These findings demonstrated that the S. borealis extract exerts its anti-hyperglycemic effect through activation of AMPK and enhancement of insulin signaling.

Vitamin C Up-regulates Expression of CD80, CD86 and MHC Class II on Dendritic Cell Line, DC-1 Via the Activation of p38 MAPK

Vitamin C is an essential water-soluble nutrient which primarily exerts its effect on host defense mechanisms and immune homeostasis, but the mechanism related to immune-potentiation is poorly understood. Since dendritic cells (DCs) are known as a potent antigen presenting cell (APC) that could enhance the antigen specific immune responses, we investigate the effects of vitamin C on activation of DCs and its related mechanism by using dendritic cell lines, DC-1. First, we found that there was no damage on DC-1 by 2.5 mM of vitamin C. In the presence of vitamin C, the expression of CD80, CD86, and MHC molecules was increased, but it was decreased by the pre-treatment of SB203580, p38 MAPK-specific inhibitor. We confirmed the phosphorylation of p38 MAPK was increased by the treatment of vitamin C. Taken together, these results suggest that vitamin C could enhance the activity of dendritic cells via the up-regulation of the expression of CD80, CD86, and MHC molecules and the activation of p38 MAPK is related to this process.

Role of phospholipase A2 in hypoxia-induced renal cell injury

The present study was designed to assess the roles of PLA2 activation and arachidonic acid (AA) metabolites in hypoxia-induced renal cell injury. Hypoxia increased LDH release in a dose-dependent manner in rabbit renal cortical slices, and this increase was significant after 20-min hypoxia. The hypoxia-induced LDH release was prevented by amino acids, glycine and alanine, and extracellular acidosis (pH 6.0). Buffering intracellular Ca2+ by a chelator, but not omission of Ca2+ in the medium produced a significant reduction in hypoxia-induced LDH release. The effect of hypoxia was blocked by PLA2 inhibitors, mepacrine, butacaine, and dibucaine. A similar effect was observed by a 85-kD cPLA2 inhibitor AACOCF3. AA increased hypoxia-induced LDH release, and albumin, a fatty acid absorbent, prevented the LDH release, suggesting that free fatty acids are involved in hypoxia-induced cell injury. These results suggest that PLA2 activation and its metabolic products play important roles in pathogenesis of hypoxia-induced cell injury in rabbit renal cortical slices.