Monosialotetrahexosylganglioside protect cerebral ischemia/reperfusion injury through upregulating the expression of tyrosine hydroxylase by inhibiting lipid peroxidation.

To explore the new mechanism of neuroprtection of monosialotetrahexosylganglioside and providing reliable theoretical foundation and experimental evidence for the emergency treatment and rehabilitation of cerebral ischemia/reperfusion injury. A rat model of cerebral ischemia/reperfusion injury was constructed and intervened with monosialotetrahexosylganglioside(5mg/kg) and lipid peroxidation inhibitor U-101033E(40mg/kg). TTC straining and neurobiological function score were used to evaluate brain injury. 4-HNE and MDA content were measured to evaluate lipid peroxidation. The expression of tyrosine hydroxilase at both mRNA and protein levels and enzyme activity were determined to evaluate the gene disfunction. Tyrosine content in brain and in serum and the DOPA content in plasma were measured to evaluate the metabolism of tyrosine. As the study shown, cerebral ischemia/reperfusion lead to brain infarction and neurobiological function losing accompany with upregulation of 4-HNE and MDA levels and downregulation of TH expression (mRNA and protein) and decreased enzyme activity. The results above mentioned can be reversed obviously by intervening with monosialotetrahexosylganglioside and lipid peroxidation inhibitor U-101033E. Toxic aldehyde accumulation leaded to disfunction of tyrosine hydroxylase and excessive tyrosine and decreased synthesis of catecholamine neurotransmitter such as dopamine and accelerated neuron cell injury. Both monosialotetrahexosylganglioside and U-101033E presented neuroprotecion by restoring the tyrosine/dopa pathway through reversing the function of tyrosine hydroxylase by inhibiting lipid peroxidation.

Mangiferin attenuates TH1/TH2 cytokine imbalance in an ovalbumin-induced asthmatic mouse model.

Mangiferin is a major bioactive ingredient in Mangifera indica Linn. (Anacardiaceae) leaves. Aqueous extract of such leaves have been used as an indigenous remedy for respiratory diseases like asthma and coughing in traditional Chinese medicine. However, underlying molecular mechanisms of mangiferin on anti-asthma remain unclear. In our present study, we investigated the anti-asthmatic effect of mangiferin on Th1/Th2 cytokine profiles and explored its underlying immunoregulatory mechanism in mouse model of allergic asthma. Mangiferin significantly reduced the total inflammatory cell counts and eosinophil infiltration, decreased the production of ovalbumin-specific IgE in serum and PGD2 in BALF. The antibody array analysis showed that mangiferin down-regulated the levels of one group of cytokines/chemokines including Th2-related IL-4, IL-5, IL-13, and others IL-3, IL-9, IL-17, RANTES, TNF-α, but simultaneously up-regulated Th1-related IFN-γ, IL-2 and IL-10 and IL-12 expression in serum. Thus it attenuates the imbalance of Th1/Th2 cells ratio by diminishing the abnormal mRNA levels of Th1 cytokines (IFN-γ and IL-12) and Th2 cytokines (IL-4, IL-5 and IL-13). Finally, mangiferin substantially inhibited the activation and expression of STAT-6 and GATA-3 in excised lung tissues. Our results suggest that mangiferin can exert anti-asthmatic effect. The underlying mechanism may attribute to the modulation of Th1/Th2 cytokine imbalance via inhibiting the STAT6 signaling pathway.