With the rapid development of biotechnology, therapeutic peptide has been a hot area in the central nervous system drugs due to its features of easy to design and target specificity. However, therapeutic peptide is difficult to cross the blood brain barrier into the central nervous system and target cells, coupled with its in vivo instability, which seriously restricts its application in central nervous system diseases. This review focuses on the progress of therapeutic peptides across the blood brain barrier targeting the central nervous system, compares and analyses the methods of increasing therapeutic peptides penetration, specificity and stability in combination with other molecules, in order to provide help for the development of central nervous system drugs.

Objective To investigate the protective effect and its mechanism of metabotropic glutamate receptor 1 ( mGluR1) negative allosteric modulator JNJ16259685 on neuron after subarachnoid hemorrhage (SAH) in rats. Methods Ninety SPF-grade SD male rats were selected. They were randomly divided into 3 groups:sham operation group (n=18),SAH+placebo group (n=36),and SAH+JNJ16259685(JNJ) group (n=36). A SAH model was induced by intravascular puncture. SAH +placebo group received intraperitoneal injection of aseptic water containing 5% dimethyl sulfoxide (DMSO) at 2,24 and 48 h after operation. The SAH+JNJ group was intraperitoneally injected with 1 mg/kg JNJ16259685 ( dissolved in sterile water in 5% DMSO). Garcia scoring criteria were used to assess neurological deficits at 72 h after SAH. Dry and wet weight method was used to detect brain edema. Evans Blue method was used to assess blood-brain barrier permeability. A calcium assay kit was used to detect the mitochondrial calcium ion concentration. Immunofluorescence staining was used to observe neuronal apoptosis. GraphPad 7. 0 software was used to conduct one-way analysis of variance in all indicators among the 3 groups. Results Compared with the sham operation group,the Garcia score (11. 0 ± 0. 4) decreased in the SAH+placebo group. The water content in left and right hemispheres was 80. 5 ± 0. 1% and 80. 3 ± 0. 2% respectively,the Evans blue dye extravasation (2. 8 ± 0. 2),basal cortical mitochondrial calcium ion concentration (2. 5 ± 0. 3),and neuronal apoptosis in basal cortex and hippocampus CA1 region (the number of active caspase-3/NeuN positive cells was 300 ±30/mm2and 20 ± 2/mm respectively) increased (all P<0. 05);and the Garcia score (13. 0 ± 0. 5) was significantly higher in the SAH+JNJ group than in the SAH+placebo group. Water content in left and right hemispheres was 79. 8 ± 0. 2% and 79. 3 ± 0. 1% respectively,Evans blue dye extravasation (1. 8 ±0. 2),basal cortex mitochondrial calcium ion concentration (1. 7 ± 0. 1),basal cortex and the number of neuronal apoptosis in hippocampal CA1 region (the number of active caspase-3/NeuN positive cells were 180 ± 10/mm2,12 ±2/mm) reduced compared with the SAH+placebo group (all P<0. 05). Conclusion After SAH,JNJ16259685 relieves cerebral edema and reduces blood-brain barrier permeability,inhibits the increase of cortical mitochondrial calcium ion concentration,and reduces neuronal apoptosis,thereby exerting neuroprotective effects.

Objective To label granulocytes in a state of differentiation in mouse bone marrow (BM) with EdU (5-ethynyl-2′-deoxyuridine) for further understanding the changes in granulocyte produc-tion at different stages of differentiation during inflammation. Methods C57BL/6 mice were intraperitoneal-ly (i.p.) injected with EdU and heat-inactivated Escherichia coli(HI E.coli). BM cells were harvested at different time points after HI E.coli injection and then stained with fluorescent-conjugated antibodies(Abs). Myeloblasts,promyelocytes,myelocytes, metamyelocytes and band and segmented neutrophils were identi-fied by fluorescence-activated cell sorting(FACS). The percentage of EdU-positive cells in each population was recorded. Results The percentage of EdU-positive myeloblasts in mice increased by 10.0% at 24 h af-ter intraperitoneal injection with HI E.coli,but decreased by 75.0% and 23.0% at 48 h and 72 h,respec-tively. The percentage of EdU-positive promyelocytes declined by 23.0%,54.5%,64.3% and 77.8% at 24 h,48 h,72 h and 96 h,respectively. The percentage of EdU-positive myelocytes increased by 60.0% and 10.0% at 24 h and 48 h,but decreased by 80.0% and 90.0% at 72 h and 96 h. The percentage of EdU-positive metamyelocytes increased by 50.0% at 24 h,but decreased by 33.3%,61.5% and 66.7% at 48 h,72 h and 96 h. The percentage of EdU-positive band and segmented cells increased by 14.0% at 24 h,but decreased by 50.0%, 77.8% and 88.0% at 48 h, 72 h and 96 h. Conclusion Emergency granulopoiesis occurred 24 h after the establishment of HI E.coli-induced model of acute peritonitis, which meant that the proliferation of myeloid precursor cells,especially that of myelocytes and metamyelocytes,was accelerated and resulted in increasing number of mature neutrophils immigrating to sites of inflammation.