The micro RNA（mi RNA） let-7 was one of the first mi RNAs to be discovered, and is highly conserved and widely expressed among species. let-7 expression increases in brain tissue after cerebral ischemia/reperfusion i...The micro RNA（mi RNA） let-7 was one of the first mi RNAs to be discovered, and is highly conserved and widely expressed among species. let-7 expression increases in brain tissue after cerebral ischemia/reperfusion injury; however, no studies have reported let-7 effects on nerve injury after cerebral ischemia/reperfusion injury. To investigate the effects of let-7 gene knockdown on cerebral ischemia/reperfusion injury, we established a rat model of cerebral ischemia/reperfusion injury. Quantitative reverse transcription-polymerase chain reaction demonstrated that 12 hours after cerebral ischemia/reperfusion injury, let-7 expression was up-regulated, peaked at 24 hours, and was still higher than that in control rats after 72 hours. Let-7 gene knockdown in rats suppressed microglial activation and inflammatory factor release, reduced neuronal apoptosis and infarct volume in brain tissue after cerebral ischemia/reperfusion injury. Western blot assays and luciferase assays revealed that mitogen-activated protein kinase phosphatase-1（MKP1） is a direct target of let-7. Let-7 enhanced phosphorylated p38 mitogen-activated protein kinase（MAPK） and c-Jun N-terminal kinase（JNK） expression by down-regulating MKP1. These findings suggest that knockdown of let-7 inhibited the activation of p38 MAPK and JNK signaling pathways by up-regulating MKP1 expression, reduced apoptosis and the inflammatory reaction, and exerted a neuroprotective effect following cerebral ischemia/reperfusion injury.展开更多
To examine the effects of Cerebrolysin on the treatment of diabetic peripheral neuropathy, we first established a mouse model of type 2 diabetes mellitus by administering a high-glucose, high-fat diet and a single int...To examine the effects of Cerebrolysin on the treatment of diabetic peripheral neuropathy, we first established a mouse model of type 2 diabetes mellitus by administering a high-glucose, high-fat diet and a single intraperitoneal injection of streptozotocin. Mice defined as diabetic in this model were then treated with 1.80, 5.39 or 8.98 m L/kg of Cerebrolysin via intraperitoneal injections for 10 consecutive days. Our results demonstrated that the number, diameter and area of myelinated nerve fibers increased in the sciatic nerves of these mice after administration of Cerebrolysin. The results of several behavioral tests showed that Cerebrolysin dose-dependently increased the slope angle in the inclined plane test（indicating an improved ability to maintain body position）, prolonged tail-flick latency and foot-licking time（indicating enhanced sensitivity to thermal and chemical pain, respectively, and reduced pain thresholds）, and increased an index of sciatic nerve function in diabetic mice compared with those behavioral results in untreated diabetic mice. Taken together, the anatomical and functional results suggest that Cerebrolysin ameliorated peripheral neuropathy in a mouse model of type 2 diabetes mellitus.展开更多
基金supported by the National Natural Science Foundation of China,No.81460193
文摘The micro RNA（mi RNA） let-7 was one of the first mi RNAs to be discovered, and is highly conserved and widely expressed among species. let-7 expression increases in brain tissue after cerebral ischemia/reperfusion injury; however, no studies have reported let-7 effects on nerve injury after cerebral ischemia/reperfusion injury. To investigate the effects of let-7 gene knockdown on cerebral ischemia/reperfusion injury, we established a rat model of cerebral ischemia/reperfusion injury. Quantitative reverse transcription-polymerase chain reaction demonstrated that 12 hours after cerebral ischemia/reperfusion injury, let-7 expression was up-regulated, peaked at 24 hours, and was still higher than that in control rats after 72 hours. Let-7 gene knockdown in rats suppressed microglial activation and inflammatory factor release, reduced neuronal apoptosis and infarct volume in brain tissue after cerebral ischemia/reperfusion injury. Western blot assays and luciferase assays revealed that mitogen-activated protein kinase phosphatase-1（MKP1） is a direct target of let-7. Let-7 enhanced phosphorylated p38 mitogen-activated protein kinase（MAPK） and c-Jun N-terminal kinase（JNK） expression by down-regulating MKP1. These findings suggest that knockdown of let-7 inhibited the activation of p38 MAPK and JNK signaling pathways by up-regulating MKP1 expression, reduced apoptosis and the inflammatory reaction, and exerted a neuroprotective effect following cerebral ischemia/reperfusion injury.
文摘To examine the effects of Cerebrolysin on the treatment of diabetic peripheral neuropathy, we first established a mouse model of type 2 diabetes mellitus by administering a high-glucose, high-fat diet and a single intraperitoneal injection of streptozotocin. Mice defined as diabetic in this model were then treated with 1.80, 5.39 or 8.98 m L/kg of Cerebrolysin via intraperitoneal injections for 10 consecutive days. Our results demonstrated that the number, diameter and area of myelinated nerve fibers increased in the sciatic nerves of these mice after administration of Cerebrolysin. The results of several behavioral tests showed that Cerebrolysin dose-dependently increased the slope angle in the inclined plane test（indicating an improved ability to maintain body position）, prolonged tail-flick latency and foot-licking time（indicating enhanced sensitivity to thermal and chemical pain, respectively, and reduced pain thresholds）, and increased an index of sciatic nerve function in diabetic mice compared with those behavioral results in untreated diabetic mice. Taken together, the anatomical and functional results suggest that Cerebrolysin ameliorated peripheral neuropathy in a mouse model of type 2 diabetes mellitus.
