Therapeutic effects of methimazole on 3,4-methylenedioxymethamphetamine-induced hyperthermia and serotonergic neurotoxicity.

3,4-methylenedioxymethamphetamine (MDMA) is a popular recreational drug, however over 200 studies demonstrate that acute (e.g. hyperthermia, rhabdomyolysis) and chronic (e.g. neurotoxicity) toxicity effects of MDMA were observed in different animals. Methimazole (MMI), an inhibitor of thyroid hormone synthesis, was found to significantly reduce the HSP72 expression of heat stress induced in fibroblasts. Hence, we attempted to understand the effects of MMI on MDMA induced changes in vivo. Male SD rats were randomly divided into four groups as follows:(a) water-saline (b) water-MDMA (c) MMI-saline and (d) MMI-MDMA group. In the temperature analysis test, MMI was found to alleviate MDMA-induced hyperthermia and increase the heat loss index (HLI), revealing its peripheral vasodilation effect. PET experiment suggested that MDMA induced elevated glucose uptake by skeletal muscles, which was resolved by MMI pretreatment. IHC staining (serotonin transporter, SERT) showed the evidence of neurotoxicity caused by MDMA (serotonin fiber loss), which was alleviated by MMI. Furthermore, the animal behaviour test (forced swimming test, FST) showed higher swimming time but lower immobility time in MMI-MDMA and MMI-saline groups. Taken together, treatment of MMI shows benefits such as lowered body temperature, alleviation of neurotoxicity and excited behaviour. However, further investigations should be conducted in the future to provide in-depth evidence for its clinical use.

Evodiamine Induces Transient Receptor Potential Vanilloid-1-Mediated Protective Autophagy in U87-MG Astrocytes.

Cerebral ischemia is a leading cause of mortality and morbidity worldwide, which results in cognitive and motor dysfunction, neurodegenerative diseases, and death. Evodiamine (Evo) is extracted from Evodia rutaecarpa Bentham, a plant widely used in Chinese herbal medicine, which possesses variable biological abilities, such as anticancer, anti-inflammation, antiobesity, anti-Alzheimer's disease, antimetastatic, antianoxic, and antinociceptive functions. But the effect of Evo on ischemic stroke is unclear. Increasing data suggest that activation of autophagy, an adaptive response to environmental stresses, could protect neurons from ischemia-induced cell death. In this study, we found that Evo induced autophagy in U87-MG astrocytes. A scavenger of extracellular calcium and an antagonist of transient receptor potential vanilloid-1 (TRPV-1) decreased the percentage of autophagy accompanied by an increase in apoptosis, suggesting that Evo may induce calcium-mediated protective autophagy resulting from an influx of extracellular calcium. The same phenomena were also confirmed by a small interfering RNA technique to knock down the expression of TRPV1. Finally, Evo-induced c-Jun N-terminal kinases (JNK) activation was reduced by a TRPV1 antagonist, indicating that Evo-induced autophagy may occur through a calcium/c-Jun N-terminal kinase (JNK) pathway. Collectively, Evo induced an influx of extracellular calcium, which led to JNK-mediated protective autophagy, and this provides a new option for ischemic stroke treatment.

EGb761 ameliorates the formation of foam cells by regulating the expression of SR-A and ABCA1: role of haem oxygenase-1.

AIMS: Accumulation of foam cells in the intima is a hallmark of early-stage atherosclerotic lesions. Ginkgo biloba extract (EGb761) has been reported to exert anti-oxidative and anti-inflammatory properties in atherosclerosis, yet the significance and the molecular mechanisms of action of EGb761 in the formation of macrophage foam cells are not fully understood. METHODS AND RESULTS: Treatment with EGb761 resulted in a dose-dependent decrease in oxidized low-density lipoprotein (oxLDL)-mediated cholesterol accumulation in macrophages, a consequence that was due to a decrease in cholesterol uptake and an increase in cholesterol efflux. Additionally, EGb761 significantly down-regulated the mRNA and protein expression of class A scavenger receptor (SR-A) by decreasing expression of activator protein 1 (AP-1); however, EGb761 increased the protein stability of ATP-binding cassette transporter A1 (ABCA1) by reducing calpain activity without affecting ABCA1 mRNA expression. Small interfering RNA (siRNA) targeting haem oxygenase-1 (HO-1) abolished the EGb761-induced protective effects on the expression of AP-1, SR-A, ABCA1, and calpain activity. Accordingly, EGb761-mediated suppression of lipid accumulation in foam cells was also abrogated by HO-1 siRNA. Moreover, the lesion size of atherosclerosis was smaller in EGb761-treated, apolipoprotein E-deficient mice compared with the vehicle-treated mice, and the expression of HO-1, SR-A, and ABCA1 in aortas was modulated similar to that observed in macrophages. CONCLUSION: These findings suggest that EGb761 confers a protection from the formation of foam cells by a novel HO-1-dependent regulation of cholesterol homeostasis in macrophages.

Resuscitation from experimental heatstroke by brain cooling therapy.

We have used hypothermic retrograde jugular venous flush to cool the brain previously and to provide better resuscitation than peripheral cold saline infusion during heatstroke in the rat. The current study was performed to assess the effects of brain cooling further on production of reactive nitrogen species, reactive oxygen species, tumor necrosis factor-alpha, and interleukin-10 in both serum and brain during heatstroke. Rats, under general anaesthesia, were randomized into the following groups and given: (a) 36 degrees C or (b) 4 degrees C saline infusion in the external jugular vein immediately after onset of heatstroke. They were exposed to an ambient temperature of 43 degrees C for exactly 70 min to induce heatstroke. When the 36 degrees C saline-treated rats underwent heat stress, their survival time values were found to be 21-25 min. Immediately after the onset of heatstroke, resuscitation with an i.v. dose of 4 degrees C saline greatly improved survival (226-268 min). Compared with the normothermic controls, the 36 degrees C saline-treated heatstroke rats displayed higher levels of brain temperature, intracranial pressure, serum and hypothalamic nitric oxide metabolite, tumor necrosis factor-alpha and dihydroxybenzoic acid as well as hypothalamic inducible nitric oxide synthase immunoreactivity. In contrast, the values of mean arterial pressure, cerebral perfusion pressure, and hypothalamic levels of local blood flow, and partial pressure of oxygen were all significantly lower during heatstroke. The cerebrovascular dysfunction, the increased levels of nitric oxide metabolites, tumor necrosis factor-alpha, and dihydroxybenzoic acid in both the serum and the hypothalamus, and the increased levels of hypothalamic inducible nitric oxide synthase immunoreactivity occurred during heatstroke were significantly suppressed by brain cooling. Although the serum and hypothalamic interleukin-10 maintained at a negligible level before stress, they were significantly elevated by brain cooling during heatstroke. These findings suggest that brain cooling may resuscitate persons who had heatstroke by decreasing overproduction of reactive nitrogen species, tumor necrosis factor-alpha, reactive oxygen species and cerebrovascular dysfunction, but increasing production of interleukin-10.