Blocking ERK signaling pathway lowers MMP-9 expression to alleviate brain edema after traumatic brain injury in rats / 南方医科大学学报

OBJECTIVE@#To investigate the effects of blocking the activation of ERK pathway on the expression of matrix metalloproteinase-9 (MMP-9) and the formation of cerebral edema in SD rats after brain injury.@*METHODS@#Ninety SD rats were randomly divided into 3 equal groups, including a sham-operated group, modified Feeney's traumatic brain injury model group, and ERK inhibition group where the ERK inhibitor SCH772984 (500 μg/kg) was injected via the femoral vein 15 min before brain trauma. At 2 h and 2 days after brain trauma, the permeability of blood-brain barrier was assessed by Evans blue method, the water content of the brain tissue was determined, and the phosphorylation level of ERK and the expression level of MMP-9 mRNA and protein were measured by RT-PCR and Western blotting.@*RESULTS@#Compared with the sham-operated group, the rats with brain trauma exhibited significantly increased level of ERK phosphorylation at 2 h and significantly increased expression of MMP-9 mRNA and protein 2 days after the injury ( < 0.01). Treatment with the ERK inhibitor significantly decreased the phosphorylation level of ERK after the injury ( < 0.01), suppressed over-expression of MMP-9 mRNA and protein 2 days after the injury ( < 0.01). The permeability of blood-brain barrier increased significantly 2 h after brain trauma ( < 0.05) and increased further at 2 days ( < 0.01); the water content of the brain did not change significantly at 2 h ( > 0.05) but increased significantly 2 d after the injury ( < 0.01). Treatment with the ERK inhibitor significantly lowered the permeability of blood-brain barrier and brain water content after brain trauma ( < 0.01).@*CONCLUSIONS@#Blocking the activation of ERK pathway significantly reduced the over-expression of MMP-9 and alleviates the damage of blood-brain barrier and traumatic brain edema, suggesting that ERK signaling pathway plays an important role in traumatic brain edema by regulating the expression of MMP-9.

Blocking ERK signaling pathway lowers MMP-9 expression to alleviate brain edema after traumatic brain injury in rats / 浙江大学学报·医学版

OBJECTIVE@#To investigate the effects of blocking the activation of ERK pathway on the expression of matrix metalloproteinase-9 (MMP-9) and the formation of cerebral edema in SD rats after brain injury.@*METHODS@#Ninety SD rats were randomly divided into 3 equal groups, including a sham-operated group, modified Feeney's traumatic brain injury model group, and ERK inhibition group where the ERK inhibitor SCH772984 (500 μg/kg) was injected via the femoral vein 15 min before brain trauma. At 2 h and 2 days after brain trauma, the permeability of blood-brain barrier was assessed by Evans blue method, the water content of the brain tissue was determined, and the phosphorylation level of ERK and the expression level of MMP-9 mRNA and protein were measured by RT-PCR and Western blotting.@*RESULTS@#Compared with the sham-operated group, the rats with brain trauma exhibited significantly increased level of ERK phosphorylation at 2 h and significantly increased expression of MMP-9 mRNA and protein 2 days after the injury ( < 0.01). Treatment with the ERK inhibitor significantly decreased the phosphorylation level of ERK after the injury ( < 0.01), suppressed over-expression of MMP-9 mRNA and protein 2 days after the injury ( < 0.01). The permeability of blood-brain barrier increased significantly 2 h after brain trauma ( < 0.05) and increased further at 2 days ( < 0.01); the water content of the brain did not change significantly at 2 h ( > 0.05) but increased significantly 2 d after the injury ( < 0.01). Treatment with the ERK inhibitor significantly lowered the permeability of blood-brain barrier and brain water content after brain trauma ( < 0.01).@*CONCLUSIONS@#Blocking the activation of ERK pathway significantly reduced the over-expression of MMP-9 and alleviates the damage of blood-brain barrier and traumatic brain edema, suggesting that ERK signaling pathway plays an important role in traumatic brain edema by regulating the expression of MMP-9.

Establishment of an HBV chronic hepatitis B infection mouse model by vivo transduction of HBV cccDNA / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To generate a mouse model of chronic hepatitis B (CHB) infection by performing in vivo transduction of hepatitis B virus (HBV) covalently closed circular (ccc)DNA.</p><p><b>METHODS</b>Nude mice were injected with HBV cccDNA at doses of 1.5, 1.0 or 0.5 mug/ml. A control group was generated by giving equal injection volumes of physiological saline. The serum levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) on post-injection days 1 and 3, weeks 1-6, 8 and 10 were assayed by reflection immunoassay. At post-injection week 10, all animals were sacrificed and liver tissues were collected. Copies of HBV DNA in serum and liver tissue were detected by real-time PCR. HBV antigens in liver tissue were detected of by immunohistochemistry. Pathological analysis of liver tissue carried out with hematoxylin-eosin staining. Linear correlation of data was determined by statistical analysis.</p><p><b>RESULTS</b>HBsAg and HBeAg were detected in sera from all three groups of cccDNA-injected mice staring at post-injection day 1 and lasting through week 10. The levels of HBsAg over the 10-week period showed two patterns of increase-decrease;the lowest level was detected at week 4 and the highest level was detected at week 8. In contrast, the levels of HBeAg over the 10-week period showed three patterns of increase-decrease; the lower levels were detected at weeks 2 and 4 and the higher levels at weeks 3 and 6. HBV DNA copies in liver tissues showed a cccDNA dose-dependent descending trend over the 10-week study period (1.5 mug/ml:1.14E+07 ± 6.51E+06 copies/g, 1.0 mug/ml:9.81E+06 ± 9.32E+06 copies/g, and 0.5 mug/ml:3.72E+06 ± 2.35E+06 copies/g; Pearson's r =0.979). HBV DNA copies in sera showed the pattern of 1.0 mug/ml cccDNA more than 1.5 mug/ml cccDNA more than 0.5 mug/ml cccDNA, and in general were higher than those detected in the liver tissues. Liver tissues from all cccDNA-injected mice showed positive immunohistochemistry staining for both HBsAg and HBeAg. HE staining showed that the liver tissues of all cccDNA-injected mice had severe fatty and vacuolar degeneration and less obvious structure of liver lobules (compared to the liver tissues from control mice).</p><p><b>CONCLUSION</b>The CHB mouse model successfully established in this study by in vivo transduction of HBV cccDNA may represent a useful tool to study the pathogenic mechanisms and potential antiviral treatments of human CHB.</p>

Activation of SDF-1/CXCR4 axis induces proliferation,migration,and tubulogenesis of human endothelial progenitor cells / 基础医学与临床

Objective To explore the effect of chemokine SDF-1 on the proliferation,migration and in vitro of human endothelial progenitor cells(EPCs).Methods The expression of CXCR4 and SDF-1 on EPCs was detected with immunocytochemistry.Proliferation,migration and in vitro tubulogenesis of EPCs was detected by MTT,Millicell chemotaxis and three-diamensional in vitro Matrigel assays,respectively.Results SDF-1 and CXCR4 were expressed on EPCs.SDF-1 induced proliferation,migration and tubulogenesis of EPCs.However,AMD3100 abolished the effects induced by SDF-1.Conclusion The SDF-1/CXCR4 axis possibly plays a critical role in regulating vasculogenesis of EPCs.