Protective effects of exogenous ß-hydroxybutyrate on paraquat toxicity in rat kidney.

In this study, we demonstrated the protective effects of ß-hydroxybutyrate (ß-HB) against paraquat (PQ)-induced kidney injury and elucidated the underlying molecular mechanisms. By histological examination and renal dysfunction specific markers (serum BUN and creatinine) assay, ß-HB could protect the PQ-induced kidney injury in rat. PQ-induced kidney injury is associated with oxidative stress, which was measured by increased lipid peroxidation (MDA) and decreased intracellular anti-oxidative abilities (SOD, CAT and GSH). ß-HB pretreatment significantly attenuated that. Caspase-mediated apoptosis pathway contributed importantly to PQ toxicity, as revealed by the activation of caspase-9/-3, cleavage of PARP, and regulation of Bcl-2 and Bax, which were also effectively blocked by ß-HB. Moreover, treatment of PQ strongly decreased the nuclear Nrf2 levels. However, pre-treatment with ß-HB effectively suppressed this action of PQ. This may imply the important role of ß-HB on Nrf2 pathway. Taken together, this study provides a novel finding that ß-HB has a renoprotective ability against paraquat-induced kidney injury.

Protective effects of phillyrin on H2O 2-induced oxidative stress and apoptosis in PC12 cells.

Oxidative stress is a major component of harmful cascades activated in neurodegenerative disorders. We sought to elucidate possible effects of phillyrin, an active constituent isolated from the Chinese medicinal herb Forsythia suspense, on hydrogen peroxide (H2O2)-induced cell death and determine the underlying molecular mechanisms in neuron-like PC12 cells. By MTT assay and lactate dehydrogenase (LDH) leakage assay, we found that phillyrin treatment effectively protected PC12 cells against H2O2-induced cell damage. H2O2 exposure induced oxidative stress in PC12 cells, as revealed by enhanced oxidative stress and decreased activities of antioxidative enzymes, which were inhibited by phillyrin pretreatment. ROS activated mitochondria-dependent apoptosis. The anti-apoptotic effects of phillyrin were also confirmed by acridine orange/ethidium bromide (AO/EB) staining. Mitochondrial membrane potential decrease, cytochrome c release, caspases activation, activation of AIF and Endo G were observed in H2O2-treated cells by rhodamine 123 or western blot. Interestingly, phillyrin effectively suppressed these changes. Moreover, phillyrin could inhibit H2O2-induced up-regulation of Bax/Bcl-2 ratio. In conclusion, phillyrin effectively inhibited H2O2-induced oxidative stress and apoptosis in PC12 cells.

Pathway of programmed cell death and oxidative stress induced by ß-hydroxybutyrate in dairy cow abomasum smooth muscle cells and in mouse gastric smooth muscle.

The administration of exogenous ß-hydroxybutyrate (ß-HB), as well as fasting and caloric restriction, is a condition associated with ß-HB abundance and decreased appetite in animals. Increased ß-HB and decreased appetite exist simultaneously in some diseases, such as bovine left displaced abomasums (LDA) and human chronic gastritis. However, the effects of ß-HB on stomach injuries have not been explored. To elucidate the possible effects of exogenous ß-HB on the stomach, mice were injected intraperitoneally with ß-HB, and bovine abomasum smooth muscle cells (BSMCs) were treated with different concentrations of ß-HB. We found that ß-HB induced BSMCs endoplasmic reticulum- and mitochondria-mediated apoptotic cell death. ß-HB promoted Bax expression and caspase-12, -9, and -3 activation while blocking Bcl-2 expression. ß-HB also promoted AIF, EndoG release and p53 expression. ß-HB acted on key molecules in the apoptotic cell death pathway and increased p38 and c-June NH2-terminal kinase phosphorylation while inhibiting ERK phosphorylation and PCNA expression. ß-HB upregulated P27 and P21 mRNA levels while downregulating cyclin and CDK mRNA levels, arresting the cell cycle. These results suggest that BSMCs treated with ß-HB can induce oxidative stress, which can be prevented by intracellular calcium chelators BAPTA/AM but not antioxidant NAC. Additionally, these results suggest that ß-HB causes ROS generation through a Ca2+-dependent mechanism and that intracellular Ca2+ levels play a critical role in ß-HB -induced apoptotic cell death. The impact of ß-HB on programmed cell death and oxidative stress in vivo was confirmed in murine experiments. For the first time, we show oxidative stress effects of ß-HB on smooth muscle. We propose that ß-HB is a possible cause of some stomach diseases, including bovine LDA.

Dietary selenium influences calcium release and activation of MLCK in uterine smooth muscle of rats.

We sought to elucidate the effects of different concentrations of dietary selenium on calcium ion release, MLCK levels, and muscle contraction in the uterine smooth muscle of rats. The selenium (Se) content of blood and of uterine smooth muscle tissues was detected by fluorescence spectrophotometry. Ca(2+) content was measured by atomic absorption spectroscopy. Calmodulin (CaM) and MLCK RNA and protein levels were analyzed by quantitative real-time polymerase chain reaction and Western blot, respectively. Dietary Se intake increased the Se levels in the blood and in uterine smooth muscle tissues and increased the Ca(2+) concentration in uterine smooth muscle tissues. The addition of Se also promoted CaM expression and enhanced MLCK activation in uterine smooth muscle tissues. In conclusion, Ca(2+), CaM, and MLCK were regulated by Se in uterine smooth muscle; Se plays a major role in regulating smooth muscle contraction in the uterus.