Memory decline is characteristic of aging and age-related neurodegenerative disorders. This study was designed to investigate the protective effect of hyperbaric oxygen (HBO) against cognitive impairment induced by D-galactose (D-gal) in mice. D-gal was intraperitoneally injected into mice daily for 8 weeks to establish the aging model. HBO was simultaneously administered once daily. The results indicate that HBO significantly reversed D-gal-induced learning and memory impairments. Studies on the potential mechanisms of this action showed that HBO significantly reduced oxidative stress by increasing superoxide dismutase, glutathione peroxidase, and catalase levels, as well as the total anti-oxidation capability, while decreasing the content of malondialdehyde, nitric oxide, and nitric oxide synthase in the hippocampal CA1 region. HBO also inhibited advanced glycation end-product formation and decreased levels of tumor necrosis factor-α and interleukin-6. Moreover, HBO significantly attenuated D-gal-induced pathological injury in the hippocampus, as well as β-amyloid protein expression and retained BDNF expression. Furthermore, HBO decreased p16, p21 and p53 gene and protein expression in the hippocampus of D-gal-treated mice. In conclusion, the protective effect of HBO against D-gal-induced cognitive impairment was mainly due to its ability to reduce oxidative damage, suppress inflammatory responses, and regulate aging-related gene expression.

Background/Aims: In this study, we examined whether the combination of hyperbaric oxygen (HBO) and diltiazem therapy provided a cardioprotective effect on myocardial ischemia-reperfusion injury (MIRI) rat model. Methods: Sixty healthy Sprague-Dawley rats were randomly divided into sham, IR, diltiazem (5 mg/kg), HBO (0.25 MPa, 60 min) and combination therapy (HBO plus diltiazem) groups. MIRI model was established by ligating the left anterior descending for 30 min, followed by 60 min of reperfusion. Results: The results show that HBO and diltiazem preconditioning significantly improves cardiac function and myocardial infarction area, increases nitric oxide, endothelial nitric oxide synthase and ATPase (Na⁺-K⁺-ATPase and Ca²⁺-Mg²⁺-ATPase) activity and decreases levels of oxygen stress, myocardial enzymes and endothelin-1. Notably, HBO and diltiazem preconditioning significantly increased Bcl-2 protein expression and decreased Bax protein and caspase-3 mRNA expression. Conclusions: These data indicate that combination therapy protected against heart MIRI by reducing oxygen stress damage, correcting energy metabolism, improving endothelial function and inhibiting cell apoptosis.

Our previous study demonstrated that hyperbaric oxygen (HBO) improved cognitive impairments mainly by regulating oxidative stress, inflammatory responses and aging-related gene expression. However, a method for preventing cognitive dysfunction has yet to be developed. In the present study, we explored the protective effects of HBO on the cholinergic system and apoptosis in D-galactose (D-gal)-treated mice. A model of aging was established via systemic intraperitoneal injection of D-gal daily for 8 weeks. HBO was administered during the last 2 weeks of D-gal injection. Our results showed that HBO in D-gal-treated mice significantly improved behavioral performance on the open field test and passive avoidance task. Studies on the potential mechanisms of this effect showed that HBO significantly reduced oxidative stress and blocked the nuclear factor-κB pathway. Moreover, HBO significantly increased the levels of choline acetyltransferase and acetylcholine and decreased the activity of acetylcholinesterase in the hippocampus. Furthermore, HBO markedly increased expression of the anti-apoptosis protein Bcl-2 and glial fibrillary acidic protein meanwhile decreased expression of the pro-apoptosis proteins Bax and caspase-3. Importantly, there was a significant reduction in expression of Aβ-related genes, such as amyloid precursor protein, β-site amyloid cleaving enzyme-1 and cathepsin B mRNA. These decreases were accompanied by significant increases in expression of neprilysin and insulin-degrading enzyme mRNA. Moreover, compared with the Vitamin E group, HBO combined with Vitamin E exhibited significant difference in part of the above mention parameters. These findings suggest that HBO may act as a neuroprotective agent in preventing cognitive impairments.

Metastasis causes approximately 90% of breast cancer-related deaths in women. Previously, we have demonstrated that 2-dodecyl-6-methoxycyclohexa-2,5-diene- 1,4-dione (DMDD) remarkably inhibited the growth of human breast cancer cells with little toxicity. In this study, we investigated the toxicity and efficacy of DMDD to treat metastatic breast tumors using an in vivo mouse model of the 4T1 mammary carcinoma. DMDD caused no observable toxicity and significantly extended the survival of 4T1 tumor-bearing mice. DMDD effectively inhibited the growth of 4T1 cells in vitro, and suppressed the growth and metastasis of mammary tumor in vivo. The levels of inflammatory cytokines in the serum (TNF-α, IL-6, IL-12, TGF-β, and VEGF) were down regulated by DMDD. Immunohistochemical analysis demonstrated that the inhibition of tumor growth and metastasis was associated with activation of Bax, cleaved caspases-3 and -9, and down-regulation of Bcl-2, MMP-2 and -9, NF-κB and IκBα. We speculate that DMDD inhibits cytokine production in the tumor cells in mice, which leads to deactivation of NF-κB pathway, and consequently inhibits the expression of many anti-apoptosis and metastasis-promoting genes, such as Bcl-2 and MMPs. Collectively, our results demonstrate the potential of DMDD as a safe and effective antitumor agent in the treatment of late-stage breast cancer.

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