Although the cognitive impairment in geriatric diabetes is common, its mechanisms remain unclear and therapies are limited. The present study investigated the effects of rosiglitazone on memory impairment in aged rats with diabetes. Diabetes was induced by streptozotocin in aged Wistar rats of 20-22 months. Then, the diabetic rats were divided randomly into the diabetic model group and rosiglitazone treatment group for assessment of cognitive function and cerebral injury at 8 weeks using Morris water maze (MWM) paradigm, real-time PCR and western blot analysis. Wistar rats of the same age were also assessed as control. In vitro, the therapeutic effect of rosiglitazone was investigated using rat chromaffin cell line PC12 cultured with high glucose and/or C-reactive protein (CRP). 8 weeks after diabetes induction aged rats exhibited marked and persistent hyperglycemia, weight loss, higher level of serum CRP and learning impairments. Enhanced cerebral inflammation in aged rats with diabetes was associated with over-activation of the nuclear factor κB (NF-κB) signalling pathway and upregulation of inflammatory cytokines (IL-6, TNFα) in the hippocampus. Compared with the diabetic group, level of serum CRP, inflammatory cytokines and over-activation of NF-κB signalling pathway in the hippocampus were restored partially concomitant with attenuation of cognitive dysfunction indicated as markedly decreased escape latency and distance during MWM test in the rosiglitazone treatment group. In vitro, high glucose significantly activated NF-κB signalling pathway and upregulated inflammatory cytokines. CRP synergistically promoted high glucose-mediated effects. Rosiglitazone significantly ameliorated the effects mediated by high glucose and CRP.These effects were significantly reversed by co-treatment with the PPARγ antagonist T0070907. These results suggest that rosiglitazone can improve cognitive function in aged rats with diabetes by inhibiting the NF-κB signal activation and decreasing the expressions of inflammatory cytokines in the hippocampus.
Purpose: To review the medicinal uses of Mahonia bealei, an important member of the genus Mahonia, with a focus on its various applications in Traditional Chinese Medicine, as well as published scientific evidence on its effectiveness.
Methods: Information in all available literature was retrieved using different search engines including NCBI, ISI Web of Knowledge and Google.
Results: Several compounds have been extracted from M. bealei. These include alkaloids, triterpenes, flavonoids, phytosterols and lignans. Traditionally, the plant is used to treat dysentery, diarrhea and inflammation. Globally, scientists have used in vitro and in vivo techniques to evaluate the usefulness of compounds extracted from M. bealei with respect to their antibacterial, anti-inflammatory, antitumor, antioxidant as well as anti-gastrin properties.
Conclusion: Different parts of this plant still remain underexplored. Moreover, comparison of the properties of the isolated compounds has not been carried out, nor are there reports on the synergistic effects of extracts of the plant. Therefore, future research to address these areas may be useful in the discovery of new therapeutic agents.
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