ABSTRACT
The hippocampus, a crucial structure for neuronal plastic response, participates in various aspects of higher function of the brain. Toxoplasma gondii is prevalent in humans and seropositivity of toxoplasma is estimated to be more than 30% in the world. This review summarizes the recent findings on the role of toxoplasma infection in hippocampus-dysfunctional diseases with an emphasis on the underlying mechanisms. Those hippocampus-dysfunctional diseases include epilepsy, schizophrenia, cognitive disorder, and depression. Also, this review discusses the potential problems or limitations of previous studies on this subject, and at the same time raises novel strategies for treating hippocampus-dysfunctional diseases, especially cryptogenic or treatment-resistant diseases.
ABSTRACT
<p><b>OBJECTIVE</b>To observe the oral acute toxicity of of (+)-usnic acid in mice and assess its cytotoxicity in rat cardiac fibroblasts.</p><p><b>METHODS</b>The mice with acute poisoning of (+)-usnic acid at different doses by oral administration were observed for toxic manifestations, and the LD(50) was determined. The survival time and survival rate of the mice receiving different doses of (+)-usnic acid were observed. Cultured rat cardiac fibroblasts were inoculated with different concentrations of (+)-usnic acid, and the cell growth inhibition rate was estimated and the IC(50) determined using MTT assay.</p><p><b>RESULTS</b>Higher dose of (+)-usnic acid resulted in more obvious symptoms of poisoning and shorter survival time of the mice. The LD(50) of (+)-usnic acid in mice by oral administration was 388 mg/kg. The manifestations of poisoning such as apathism, pilomotor, chill, dyspnea, torpidity and anorexia was observed. Rat cardiac fibroblasts incubated with (+)-usnic acid showed obvious growth inhibition, which was positively correlated to the dose of (+)-usnic acid, and high dose of (+)-usnic acid caused severe cell injuries. The IC(50) of (+)-usnic acid in rat cardiac fibroblasts was 322 microg/ml.</p><p><b>CONCLUSION</b>(+)-usnic acid is a natural compound of low toxicity in mice, and low to medium dose of (+)-usnic acid dose not produce obvious cytotoxicity.</p>