Oxidative stress plays an important role in neurodegenerative disorders. Ampelopsin, a flavonoid abundant in Rattan tea (Ampelopsis grossedentata), is a potent antioxidant and its neuroprotective effect against H₂O₂-induced apoptosis in PC12 cells is investigated here for the first time. It was found that treatment of cells with ampelopsin for 1 h significantly reduced the loss of vitality, LDH release and apoptosis and inhibited the formation of reactive oxygen species (ROS). Ampelopsin was able to prevent the activation of p38 induced by H₂O₂. In addition, up-regulation of heme oxygenase-1 (HO-1) expression by ampelopsin was shown to be both dose- and time-dependent. Mechanically, HO-1 expression induced by ampelopsin was found to be due to activation of the ERK and Akt signaling pathways, because it was almost completely blocked by the specific inhibitors of ERK and Akt. These results suggest that ampelopsin increases cellular antioxidant defense through activation of the ERK and Akt signaling pathways, which induces HO-1 expression and thereby protects PC12 cells from H₂O₂-induced apoptosis.
In order to explore the high performance bivalent DNA-based vaccine against schistosomes, SjFABP and Sj26GST were selected and used to construct a vaccine. Two strategies were used to construct the bivalent DNA vaccine. In the first strategy, a plasmid encoding antigen in the secreted form was used, while in the other, a plasmid encoding a truncated form of SjFABP and Sj26GST targeted to the cell surface was used. Various parameters, including antibody and cytokine response, proliferation, histopathological examination, and characterization of T cell subsets were used to evaluate the type of immune response and the level of protection against challenge infection. Injection with secreted pIRES-sjFABP-sj26GST significantly increased the levels of antibody, splenocyte proliferation, and production of IFN-γ, compared with membrane-anchored groups. Analysis of splenic T cell subsets showed that the secreted vaccine significantly increased the percentage of CD3+CD4+ and CD3+CD8+ T cells. Liver immunopathology (size of liver granulomas) was significantly reduced in the secreted group compared with the membrane-anchored groups. Moreover, challenge experiments showed that the worm and egg burdens were significantly reduced in animals immunized with recombinant vaccines. Most importantly, secreted Sj26GST-SjFABP markedly enhanced protection, by reducing worm and egg burdens by 31.8% and 24.78%, respectively, while the membrane-anchored group decreased worm and egg burdens by 24.80% and 18.80%, respectively. Taken together, these findings suggest that the secretory vaccine is more promising than the membrane-anchored vaccine, and provides support for the development and application of this vaccine.
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