Neuroprotective effect of a novel Chinese herbal decoction on cultured neurons and cerebral ischemic rats.

BACKGROUND: Historically, traditional Chinese medicine has been widely used to treat stroke. Based on the theory of Chinese medicine and the modern pharmacological knowledge of herbal medicines, we have designed a neuroprotective formula called Post-Stroke Rehabilitation (PSR), comprising seven herbs - Astragalus membranaceus (Fisch.) Bunge, Salvia miltiorrhiza Bunge, Paeonia lactiflora Pall., Cassia obtusifolia L., Ligusticum chuanxiong Hort., Angelica sinensis (Oliv.) Diels, and Glycyrrhiza uralensis Fisch. We aim to examine the neuroprotective activity of PSR in vitro and in vivo, and to explore the underlying molecular mechanisms, to better understand its therapeutic effect and to further optimize its efficacy. METHODS: PSR extract or vehicle was applied to primary rat neurons to examine their survival effects against N-methyl-D-aspartate (NMDA)-elicited excitotoxicity. Whole-cell patch-clamp recording was conducted to examine the NMDA-induced current in the presence of PSR. ERK- and CREB-activation were revealed by western blot analysis. Furthermore, PSR was tested for CRE promoter activation in neurons transfected with a luciferase reporter. The protective effect of PSR was then studied in the rat middle cerebral artery occlusion (MCAO) model. MCAO rats were either treated with PSR extract or vehicle, and their neurobehavioral deficit and cerebral infarct were evaluated. Statistical differences were analyzed by ANOVA or t-test. RESULTS: PSR prominently reduced the death of cultured neurons caused by NMDA excitotoxicity in a dose-dependent manner, indicating its neuroprotective property. Furthermore, PSR significantly reduced NMDA-evoked current reversibly and activated phosphorylation of ERK and CREB with distinct time courses, with the latter's kinetics slower. PSR also triggered CRE-promoter activity as revealed by the increased expression of luciferase reporter in transfected neurons. PSR effectively reduced cerebral infarct and deficit in neurological behavior in MCAO rats when PSR decoction was administered starting either 6 days before or 6 h after onset of ischemia. CONCLUSIONS: PSR is neuroprotective both in vitro and in vivo - it protects cultured neurons against NMDA excitotoxicity, and effectively reduces ischemic injury and neurobehavioral deficit in MCAO rats in both the pre- and post-treatment regimens. The underlying neuroprotective mechanisms may involve inhibition of NMDA receptor current and activation of ERK and CREB. This study provides important preclinical data necessary for the further development of PSR for stroke treatment.

Proliferation of Lactobacillus plantarum in solid-state fermentation of oats.

In an attempt to introduce probiotic functionalities to breakfast cereals and similar food products, the technique of solid-state fermentation (SSF) was applied to cultivate Lactobacillus plantarum (NCIMB 8826) on oat bran and spent oats after lipid extraction by supercritical CO(2) extraction. When compared to the frequently favored submerged processes for bacterium incubation, SSF presents not only the potential of simple downstream processing but also a more natural growth environment for the target bacterium. Preliminary studies confirmed that oat bran contained balanced nutrients to support a 25-fold bacterium propagation within a range of moisture content from 50% to 58% after a 36-h cultivation. Limited hydrolysis of the raw materials by the enzyme complex from submerged incubation of Aspergillus awamori and A. oryzae to increase nutrient accessibility extended the exponential growth phase and enhanced bacterial growth by over 183-fold. The process with the most potential, however, was to simultaneously grow both fungi aerobically on the raw materials in solid state to achieve sufficient hydrolysis, followed by controlled fungal autolysis at 65 degrees C prior to anaerobic bacterium incubation. Following this process bacterium population reached a maximum of 7.3 x 10(9) cells in each gram of the fermented solids, corresponding to a 1653-fold increase from the point of inoculation.