ABSTRACT
Objective To observe the ultrastructure of blood-brain barrier in the nude mouse model of brain me-tastases from lung cancer by transmission electron microscopy using lanthanum nitrate tracing.Methods PC-9 cells (1 × 106/0.1 mL) in logarithmic phase were respectively injected into six nude mice ( model group) selected from eight nude mice randomly via the left ventricle, the other two mice without any treatment as the control group.The general status of the mice was observed after implantation.In the fourth week all the mice were sacrificed and brain tissue samples were taken and prepared for transmission electron microscopic observation using lanthanum nitrate tracing.besides, the lung and brain were removed and stained with HE to detect the presence of tumor metastasis.Results Mice in the model group began to lose weight almost simultaneously in the third week and became moribund slowly, and were all sacrificed at the fourth week when showing clear signs of cachexia.At autopsy, the thoraxes were clear, with normal lungs.Histology showed evidence of brain metastasis in all the six mice.The electron microscopy showed that lathanum nitrate tracer was escaped from the capillaries and diffusely or sparsely distributed in the brain tissues of the model group mice, however lathanum nitrate tracer was still confined in the capillary lumen in the mice of control group.Conclusions The diffuse lathanum nitrate tracer in the brain parenchymal tissue indicates the impairment of blood-brain barrier in the nude mouse model of lung cancer brain metastasis and the formation of these metastases is accompanied with the destruction of blood brain barrier.
ABSTRACT
Objective:To explore the effects of lanthanum nitrate low-dose on 2 type diabetic rat pancreas INSR ,IRS1 and apoptosis of cells.Methods:The 50 male Wistar rats were randomly divided into normal control group (10) and model group(40),and were given normal diet and high-fat high-sugar diet.After 8 weeks,making the module intraperitoneal injection of streptozotocin (STZ,30 mg/kg) rats to induce type 2 diabetes model ,after a successful modeling experimental animals were divided into three groups namely the control group,diabetic model group and La(NO3)3 treatment group,three groups of rats were given daily saline,saline,lanthanum (0.2 mg/kg) nitrate administered a month ,then were sacrificed blood and pancreas.By radioimmunoassay to detect glucose ,insulin levels(in rat serum);by ELISA to detect the protein content of INSR and IRS 1(in rat serum);by immunohistochemistry to detect the protein expression levels of INSR and IRS1(in rat pancreas tissue);TUNEL apoptosis detection kit was used to detect pancreatic tissue percentage of apoptosis;HE staining was used to detect pathological changes of the pancreas.Results: Compared with the normal control group,diabetic model rats blood glucose and pancreatic tissue apoptosis rate were significantly increased ,blood insulin,INSR and IRS1 protein content and pancreatic tissue the protein expression levels of INSR and IRS 1 were significantly reduced ,difference was statistically significant ( P<0.01 );La( NO3 ) 3 treatment group blood glucose and pancreatic tissue apoptosis rate were slightly elevated ,blood insulin , INSR and IRS1 protein content and pancreatic tissue the protein expression levels of INSR and IRS 1 were slightly reduced significantly(P<0.05);Light microscopy showed pancreatic tissue in the control group closely arranged ,plump,large volume islet pancreatic tissue of diabetic rats in groups evacuate more smaller islet volume ,pancreatic tissue lanthanum nitrate basic set tight,plump,slightly islet volume small.Conclusion:Oral lanthanum nitrate can be lowered blood sugar levels and inhibiting apoptosis of pancreatic tissue ,increased insulin levels and the protein expression levels of INSR and IRS 1 in pancreatic tissue ,have a protective effect on diabetic rat pancreas .
ABSTRACT
By using electron microscopy, the paranodal region and axo-glial junction were examined in optic nerves of rats aged 14 days. The paranodal region was characterized in longitudinal sections by the sequential termination of the myelin lamellae, beginning proximally with the innermost and ending, at the Ranvier node, with the outermost lamella. The termination of each lamella was accom- panied by a separation of the major dense line of the compact myelin and the consequent formation of a "loop" of glial cytoplasm. Each paranodal loop inde- nted the axonal surface as it became junctionally apposed to the axolemma. The periaxonal extracellular space, 10-20nm in width in the internodal region and reduced at the paranodal junction to approximately 3nm, forming an axo-glial junction, which was thought to be held together by dense structure. The parano- dal junction seems to serve strong adhesion between the apposed axonal and glial membranes. Conduction of the nerve impulses in myelinated axons was saltatory. Axons and sheath cells probably maintain vital communication with one another, presumably at the paranodal junctional complex. This communication was viewed as vital to the stability and maintenance of myelin. We found some clear vesi- cles in axoplasm near the Ranvier node and speculated that there were endocyto- sis and exocytosis in paranodal region. This was a direct morphological evidence supporting metabolic coupling between axons and sheeth cells.
ABSTRACT
Objective To study the change in blood-brain barrier (BBB) permeability in dog with craniocerebral gunshot injury and its significance. Methods Twelve dogs were randomly divided into control group, 15min ofter penetrating craniocerebral injury (PCI) group, 1h after PCI group and 6h after PCI group (n=3). The injury was produced by a small-calibre rifle made in Germany (type 5.56mm, weight of bullet 2.57g). Lanthanum nitrate was infused through the heart. The changes in BBB permeability were observed under electronic microscope. Results In 15min PCI group and 1h PCI group, changes in BBB permeability was observed, with manifestation of opening of tight junctions, with lanthanum nitrate particles passing through BBB into the brain tissues. These changes were more marked in 1h PCI group. Comparing with the above two groups, even more lanthanum nitrate particles were found in the brain tissue in the 6h group (P