Pyrroloquinoline Quinone Resists Denervation-Induced Skeletal Muscle Atrophy by Activating PGC-1α and Integrating Mitochondrial Electron Transport Chain Complexes.

Denervation-mediated skeletal muscle atrophy results from the loss of electric stimulation and leads to protein degradation, which is critically regulated by the well-confirmed transcriptional co-activator peroxisome proliferator co-activator 1 alpha (PGC-1α). No adequate treatments of muscle wasting are available. Pyrroloquinoline quinone (PQQ), a naturally occurring antioxidant component with multiple functions including mitochondrial modulation, demonstrates the ability to protect against muscle dysfunction. However, it remains unclear whether PQQ enhances PGC-1α activation and resists skeletal muscle atrophy in mice subjected to a denervation operation. This work investigates the expression of PGC-1α and mitochondrial function in the skeletal muscle of denervated mice administered PQQ. The C57BL6/J mouse was subjected to a hindlimb sciatic axotomy. A PQQ-containing ALZET® osmotic pump (equivalent to 4.5 mg/day/kg b.w.) was implanted subcutaneously into the right lower abdomen of the mouse. In the time course study, the mouse was sacrificed and the gastrocnemius muscle was prepared for further myopathological staining, energy metabolism analysis, western blotting, and real-time quantitative PCR studies. We observed that PQQ administration abolished the denervation-induced decrease in muscle mass and reduced mitochondrial activities, as evidenced by the reduced fiber size and the decreased expression of cytochrome c oxidase and NADH-tetrazolium reductase. Bioenergetic analysis demonstrated that PQQ reprogrammed the denervation-induced increase in the mitochondrial oxygen consumption rate (OCR) and led to an increase in the extracellular acidification rate (ECAR), a measurement of the glycolytic metabolism. The protein levels of PGC-1α and the electron transport chain (ETC) complexes were also increased by treatment with PQQ. Furthermore, PQQ administration highly enhanced the expression of oxidative fibers and maintained the type II glycolytic fibers. This pre-clinical in vivo study suggests that PQQ may provide a potent therapeutic benefit for the treatment of denervation-induced atrophy by activating PGC-1α and maintaining the mitochondrial ETC complex in skeletal muscles.

Effect of Sanguis draconis (a dragon's blood resin) on streptozotocin- and cytokine-induced ß-cell damage, in vitro and in vivo.

The study was to examine the effects of Sanguis draconis ethanol extract (SDEE) on streptozotocin (STZ)- and cytokine-induced ß-cell damage. In vitro, SDEE did not cause cytotoxicity below 200 µg/ml, and can prevent STZ (5mM)-induced cell death and apoptosis below 100 µg/ml on RIN-m5F cells. SDEE inhibits IL-1ß/IFN-γ-stimulated NO, TNF-α release, and iNOS expression. Furthermore, SDEE suppressed the IL-1ß/IFN-γ- or STZ-induced p65 expression of NF-κB, which is associated with inhibition of IκB-α degradation. In vivo, treatment of ICR mice with STZ (100 mg/kg, i.p. single injection) resulted in hyperglycemia and hypoinsulinemia, which was further evidenced by blood glucose and plasma insulin. The diabetogenic effects of STZ were completely prevented when mice were orally administered with SDEE for 3 weeks, however, the blood glucose and plasma insulin showed no significant change after SDEE administration alone. In addition, SDEE also can inhibit STZ-induced iNOS protein expression, pancreatic injury and lipid peroxidation. In conclusions, the molecular mechanism by which SDEE inhibits iNOS gene expression appears to involve the inhibition of NF-κB activation. These results suggest the possible therapeutic value of S. draconis and could be potentially developed into a novel drug for preventing the progression of diabetes mellitus.

Biphasic effect of curcumin on morphine tolerance: a preliminary evidence from cytokine/chemokine protein array analysis.

The aim of this study was to evaluate the effect of curcumin on morphine tolerance and the corresponding cytokine/chemokine changes. Male ICR mice were made tolerant to morphine by daily subcutaneous injection for 7 days. Intraperitoneal injections of vehicle, low-dose or high-dose curcumin were administered 15 min after morphine injection, either acutely or chronically for 7 days to test the effect of curcumin on morphine-induced antinociception and development of morphine tolerance. On day 8, cumulative dose-response curves were generated and the 50% of maximal analgesic dose values were calculated and compared among groups. Corresponding set of mice were used for analyzing the cytokine responses by antibody-based cytokine protein array. Acute, high-dose curcumin enhanced morphine-induced antinociception. While morphine tolerance was attenuated by administration of low-dose curcumin following morphine injections for 7 days, it was aggravated by chronic high-dose curcumin following morphine injection, suggesting a biphasic effect of curcumin on morphine-induced tolerance. Of the 96 cytokine/chemokines analyzed by mouse cytokine protein array, 14 cytokines exhibited significant changes after the different 7-day treatments. Mechanisms for the modulatory effects of low-dose and high-dose curcumin on morphine tolerance were discussed. Even though curcumin itself is a neuroprotectant and low doses of the compound serve to attenuate morphine tolerance, high-doses of curcumin might cause neurotoxicity and aggravate morphine tolerance by inhibiting the expression of antiapoptotic cytokines and neuroprotective factors. Our results indicate that the effect of curcumin on morphine tolerance may be biphasic, and therefore curcumin should be used cautiously.

Myrrh mediates haem oxygenase-1 expression to suppress the lipopolysaccharide-induced inflammatory response in RAW264.7 macrophages.

OBJECTIVES: To elucidate a novel anti-inflammatory mechanism of myrrh against lipopolysaccharide (LPS)-induced inflammation. METHODS: RAW264.7 macrophages were cultured in DMEM and then cells were treated with LPS or LPS plus a myrrh methanol extract (MME) for 24h. The culture medium was collected for determination of nitric oxide (NO), prostaglandin (PG)E(2) , interleukin (IL)-1ß, and tumour necrosis factor (TNF)-α, and cells were harvested by lysis buffer for Western blot analysis. KEY FINDINGS: Our data showed that treatment with the MME (1∼100µg/ml) did not cause cytotoxicity or activate haem oxygenase-1 (HO-1) protein synthesis in RAW264.7 macrophages. Furthermore, the MME inhibited LPS-stimulated NO, PGE(2) , IL-1ß and TNF-α release and inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 protein expression. Zn(II) protoporphyrin IX, a specific inhibitor of HO-1, blocked the inhibition of iNOS and COX-2 expression by the MME. CONCLUSIONS: These results suggest that among mechanisms of the anti-inflammatory response, the MME inhibited the production of NO, PGE(2) , IL-1ß and TNF-α by downregulating iNOS and COX-2 gene expression in macrophages and worked through the action of HO-1.

A minimal stress model for the assessment of electroacupuncture analgesia in rats under halothane.

The use of anesthetics in acupuncture analgesia is controversial. We evaluate a steady-state light anesthesia model to test whether minimal stress manipulation and reliable measurement of analgesia could be simultaneously achieved during electroacupuncture (EA) in animals. A series of experiments were performed. Firstly, EA compliance and tail-flick latencies (TFL) were compared in rats under 0.1%, 0.3%, 0.5%, 0.7%, or 1.1% halothane for 120min. Under 0.5% halothane, TFL were then measured in groups receiving EA at intensity of 3, 10 or 20 volt (V), 1 or 2mg/kg morphine, 20V EA plus naloxone, or control. Subsequently, the effect of EA on formalin-induced hyperalgesia was tested and c-fos expression in the spinal dorsal horn was analyzed. Rats exhibited profound irritable behaviors and highly variable TFL under 0.1% or 0.3% halothane, as well as a time-dependent increase of TFL under 0.7% or 1.1% halothane. TFL remained constant at 0.5% halothane, and needle insertion and electrical stimulation were well tolerated. Under 0.5% halothane, EA increased TFL and suppressed formalin-induced hyperalgesia in an intensity-dependent and naloxone-reversible manner. EA of 20V prolonged TFL by 74%, suppressed formalin-induced hyperalgesia by 32.6% and decreased c-fos expression by 29.7% at the superficial and deep dorsal horn with statistically significant difference. In conclusion, 0.5% halothane provides a steady-state anesthetic level which enables the humane application of EA stimulus with the least interference on analgesic assessment. This condition serves as a minimal stress EA model in animals devoid of stress-induced analgesia while maintaining physiological and biochemical response in the experiment.