[Optimization of expression conditions and activity identification of hepatocyte-targeting peptide-human endostatin].

To obtain sufficient purified and active fusion protein-hepatocyte-targeting peptide-human endostatin (HTP-rES), we studied the growth curve and the optimal induction timing of BL21/pET21b-HTP-rES. Different conditions of pH value, induction time, induction concentration and induction temperature were optimized by univariate analysis. After washing, refolding and purifying, the activity of fusion protein was identified by flow cytometry and 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT). Results show that the logarithmic growth phase of BL21/pET21b-HTP-rES was from 1.5 h to 3.5 h, the optimum expression conditions were pH 8.0, 0.06 mmol/L IPTG, at 42 ℃ for 5 h. The purity of inclusion bodies was up to 60% after washing. The purity of target protein was more than 95% after refolding and purification. Our findings provide the foundation for further biological activity and drug development.

[Protective effect of Yimucao (Herba leonuri) injection against cerebral ischemia: an experimental study in mice and rats].

OBJECTIVE: To investigate the protective effect and mechanism of Yimucao (Herba leonuri) injection against experimental cerebral ischemia. METHODS: Mouse models of cerebral ischemia induced by bilateral carotid artery occlusion or potassium cyanide and rat models of middle cerebral artery occlusion (MCAO)-induced cerebral ischemia/reperfusion injury were established to evaluate the protective effect of Yimucao injection by measuring the changes in cerebral malondialdehyde (MDA) content and the activities of superoxide dismutase (SOD) and lactate dehydrogenase (LDH) after the injections. RESULTS: Yimucao injection significantly lowered the cerebral index of mice with cerebral ischemia, prolonged the survival time of mice poisoned with potassium cyanide, resulting also in significantly decreased MDA content and increased activities of SOD and LDH in the brain tissue of rats after a 10-min cerebral ischemia followed by 30 min of reperfusion. CONCLUSION: Yimucao injection provides protective effect against experimental cerebral ischemia.