ABSTRACT
Objective To investigate the effect of polylactic-co-glycolic acid (PLGA)/graphene oxide (GO) nanofibers combined with brain derived neurotrophic factor (BDNF) on neural stem cells (NSCs) proliferation and differentiation as well as on the spinal cord injury repair.Methods PLGA/GO nanofibers were manufactured and absorbed with BDNF,and the microstructure of PLGA/GO nanofibers was observed by scanning electron microscope.The loading efficiency and release curve of BDNF on PLGA/GO nanofibers were measured by ELISA.NSCs were implanted on the surface of PLGA/GO and PLGA/GO/BDNF nanofibers.The absorbance values of each group were measured by MTT method,and the expression of Tuj-1 was observed by immunofluorescence and PCR.A total of 30 female SD rats were divided into control group (n =10),PLGA/GO group (n =10) and PLGA/GO/BDNF group (n =10) according to random number table.T9 spinal cord tissue was cut by Venus scissors to establish spinal cord hemisection injury model of rats.PLGA/GO and PLGA/GO/BDNF nanofibers were implanted onto the surface of injury site.BBB score was used to assess the motion functional recovery of the rats at 1,7,14 and 28 days after operation.Immunofluorescence staining of neuron specific nucleoprotein (NeuN)and glial fibrillary acidic protein (GFAP) were performed to observe the expressions of neurons and astrocytes at the injured site respectively one month after injury.Results The PLGA/GO nanofibers showed an irregular smooth fiber-like structure,and the average fiber diameter was (987.5 ± 176.3)nm.NSCs could differentiate into neurons on the nanofibers.The result of ELISA showed loading rate of BDNF on PLGA/GO nanofibers was about 47.5％.The release curve showed that BDNF was first released about 30％ on the first day and then about 60％ on the 21st day.The results of MTT and PCR showed that optical density value and Tuj-1 gene expression in the PLGA/GO/BDNF group were significantly higher than those in the PLGA/GO group (P ＜ 0.05).The animal experiment results showed that the BBB score of PLGA/GO/BDNF group was (15.3 ±0.7) points at 28 days after injury,which was significantly higher than that of the injury control group [(11.8 ± 0.8) points] and that of PLGA/GO group [(12.7 ±0.8) points] (P ＜ 0.05).Immunofluorescence results showed that the expression of NeuN in PLGA/GO/BDNF group was 13.7 ± 2.2,significantly higher than that in injury control group (4.3 ± 2.9) (P ＜0.05),and the expression of GFAP in PLGA/GO group was (25.6 ± 4.3) ％ significantly lower than that in injury control group [(38.5 ± 6.2) ％] and PLGA/GO group [(36.7 ± 7.3) ％] (P ＜ 0.05).Conclusion PLGMGO nanofibers combined with BDNF can effectively promote the proliferation and neuron differentiation of NSCs in vitro and repair spinal cord injury in vivo through orthotopic transplantation at the injury site.
ABSTRACT
BACKGROUND:At present, spinal cord ischemia/reperfusion injury is considered as the main reason for secondary paralysis after spinal decompression, and to control the levels of stress-related proteins and excitatory amino acids plays an important role in the treatment of spinal cord ischemia/reperfusion injury. OBJECTIVE:To investigate the expression level of protein disulfide-isomerase A3 (PDIA3) after spinal cord ischemia/reperfusion injury in rabbits. METHODS:Thirty-six New Zealand white rabbits were enrolled, the models of spinal cord ischemia/reperfusion injury were established using Zivin's method, and were then randomized into six groups (n=6 per group). The rabbit abdominal aorta in control group was exposed without vascular occlusion and then the abdominal cavity was closed 30 minutes later. In experimental groups, the abdominal aorta was blocked for 30 minutes, followed by 0, 6, 12, 24 and 48 hours of reperfusion, and then the abdominal cavity was closed. The neurological function was evaluated with a modified Tarlov score. The L3-5lumbar vertebrae were removed, and PDIA3 was screened by two-dimensional fluorescence differential gel electrophoresis combined with mass spectrometry, and then its temporal and spatial changes in the spinal cord were detected by western blot assay and immunohistochemistry. RESULTS AND CONCLUSION:The function of hind limbs was improved in all the experimental groups after spinal cord ischemia/reperfusion injury, and the modified Tarlov scores reached the peak at 24 hours after schemia/reperfusion injury, and decreased slightly at 48 hours. The expression of PDIA3 in the control group showed clear imprinting, which was slightly strengthened at 0 hour, became more strengthened at 6-12 hours, significantly reduced to the minimum level at 24 hours, and returned to the level of 6-12 hours at 48 hours after ischemia/reperfusion. Immunohistochemical results showed that there was visible PDIA3 in the cytoplasm of neurons, and the expression level in the interneurons was significantly higher than that in the motor neurons. These results suggest that upregulated PDIA3 appears in the development and progression of spinal cord ischemia/reperfusion injury, indicating that PDIA3 is closely related to spinal cord ischemia/reperfusion injury, which can be used as a new diagnosis and treatment target.
ABSTRACT
ABSTRACT This research aimed to discover the distribution and the primary influence factors of Cu in the soil-rice systems of tropical farmland. Soil samples of farmland and rice plant (stalk and polished rice) from the western region of Hainan Island were collected and studied. The results showed that the average Cu content in the topsoil of the study area was 15.75 mg kg-1; the highest Cu content (45.92 mg kg-1) was found in the rice fields of the northern area, where pyroclastic parent material is distributed. Thus, there is a potential for Cu contamination of the rice grown in this region. The average contents of Cu in the rice stalks and polished rice were 16.9 and 5.68 mg kg-1, respectively, indicating that the stalks had a larger capacity for Cu bioaccumulation than the polished rice. The bioaccumulation factor (BAF) of Cu in rice was found to decrease with increased Cu contents in the soil. In regards to the northern farmlands with high Cu contents in the soil derived from pyroclastic deposits, an alkaline fertilizer should be used to prevent the risk of Cu pollution in the polished rice, as soil acidification can promote the uptake and accumulation of Cu to some extent.
ABSTRACT
Aim To investigate the direct effects and mechanism of carvedilol on HERG channel stably expressing in human embryonic kidney-293(HEK293) cells.Methods Whole-cell patch-clamp technique was used to record HERG current and kinetic curves in single cells.Western blot methods were used to investigate the expression of HERG channel in different concentration of carvedilol.Result Carvedilol decreased HERG current in a concentration-dependent manner with an IC50 539.6 nmol?L-1,Hillslope-0.64.The time constants of onset of inactivation and deactivation were accelerated.Other kinetcs(activation,inactivation,recovery from inactivation)had no significant changes.Based on western result,carvedilol had no effect on the generation and trafficking of HERG protein.Conclusion Carvedilol inhibits the transfected HERG channels by influencing the open state which is the probable anti-arrhythmic mechanism.There is no relationship between carvedilol and HERG channel expression.