Tetramethyl pyrazine exerts anti-apoptotic and antioxidant effects in a mouse model of MPTP-induced Parkinson's disease via regulation of the expressions of Bax, Bcl-2, Nrf2 and GCLC

Purpose: To investigate the effect of tetramethyl pyrazine (TMP) on MPTP)-mediated neuronal apoptosis and oxidative imbalance in mice, and the mechanism of action involved. Methods: Forty-five mice were assigned evenly to blank control, MPTP and TMP groups. The protein concentrations of Bax, Bcl-2, cytochrome C (Cyt c), Nrf2, GCLC and cleaved caspase-3; and levels of glutathione (GSH) and thiobarbituric acid reactive products (TBARS) were evaluated and compared amongst the groups. Results: Cyt c, Bax, and cleaved caspase-3 protein levels in TMP group were significantly lower than those in MPTP group, while Bcl-2 protein expression was higher in TMP group than in MPTP mice (p < 0.05). Furthermore, TBARS was lower in TMP group than in MPTP group, while GSH level increased, relative to MPTP mice. The levels of Nrf2 and GCLC were significantly higher in TMP group than in MPTP group (p < 0.05). Conclusion: Tetramethyl pyrazine exerts anti-apoptotic and antioxidant effects on MPTP-mediated Parkinsonism via regulation of the expressions of Bax, Bcl-2, Nrf2 and glutamate-cysteine ligase catalytic subunit. Thus, TMP has potential for use in the treatment Parkinson’s disease

Ameliorated ConA-Induced Hepatitis in the Absence of PKC-theta

Severe liver injury that occurs when immune cells mistakenly attack an individual's own liver cells leads to autoimmune hepatitis. In mice, acute hepatitis can be induced by concanavalin A (ConA) treatment, which causes rapid activation of CD1d-positive natural killer (NK) T cells. These activated NKT cells produce large amounts of cytokines, which induce strong inflammation that damages liver tissues. Here we show that PKC-θ−/− mice were resistant to ConA-induced hepatitis due to essential function of PKC-θ in NKT cell development and activation. A dosage of ConA (25 mg/kg) that was lethal to wild-type (WT) mice failed to induce death resulting from liver injury in PKC-θ−/− mice. Correspondingly, ConA-induced production of cytokines such as IFNγ, IL-6, and TNFα, which mediate the inflammation responsible for liver injury, were significantly lower in PKC-θ−/− mice. Peripheral NKT cells had developmental defects at early stages in the thymus in PKC-θ−/− mice, and as a result their frequency and number were greatly reduced. Furthermore, PKC-θ−/− bone marrow adoptively transferred to WT mice displayed similar defects in NKT cell development, suggesting an intrinsic requirement for PKC-θ in NKT cell development. In addition, upon stimulation with NKT cell-specific lipid ligand, peripheral PKC-θ−/− NKT cells produced lower levels of inflammatory cytokines than that of WT NKT cells, suggesting that activation of NKT cells also requires PKC-θ. Our results suggest PKC-θ is an essential molecule required for activation of NKT cell to induce hepatitis, and thus, is a potential drug target for prevention of autoimmune hepatitis

Effect of oxymatrine on hypoxic-ischemic brain injury in neonatal rats

Purpose: To study the influence of oxymatrine on hypoxic-ischemic brain injury (HIBI) in neonatal rats. Methods: Newborn SPF Sprague-Dawley (SD) rats were randomly assigned to 3 groups (10 rats/group): control, HIBI and oxymatrine groups. Neurobehavioral latency of each rat was determined after 48 h of treatment, and pathological changes in rat cerebral cortex were evaluated using H&E staining. Hippocampal neurons prepared from rat brain tissue were grouped and treated as per the above in vivo study. Cell survival and neuronal apoptotic changes were measured with CCK-8 and flow cytometric analysis, respectively, while protein expressions of bcl-2, mcl-1, bax, caspase-3, PI3K, p- PI3K, Akt, p-Akt, GSK3β and p-GSK3β were determined with Western blotting. Results: Treatment of HIBI rats with oxymatrine significantly reduced their neurobehavioral latencies (reflex, cliff avoidance reflex, and negative reflex (latencies), but repaired HIBI-induced histological damage in rat cerebral cortex (p < 0.05). It also significantly enhanced the survival of rat hippocampal neurons, while reducing neuronal apoptosis (p < 0.05). Moreover, oxymatrine significantly upregulated bcl-2, mcl-1, p-PI3K, AKT, p-AKT, GSK3β and p-GSK3β protein expressions, but i significantly downregulated the protein expressions of bax and caspase-3 in cerebral cortex of HIBI rat (p < 0.05). Conclusion: These results indicate that oxymatrine reduces neuronal apoptosis and alleviates HIBI in rats via the regulation of proteins associated with PI3K/Akt/GSK3β signal pathway. This finding provides a new research direction on novel botanical monomers for treating HIBI