Effects of sciatic nerve electrical stimulation on motor function and expression of BDNF⁃TrkB in rats with spinal cord inj ury / 安徽医科大学学报

Objectives @#To investigate the effect of sciatic nerve electrical stimulation ( SNES) on motor function recovery in rats with incomplete spinal cord injury (SCI) and its possible mechanism.@*Methods @#The incomplete SCI model was constructed by modified Allen ′s method. Forty⁃five Sprague⁃Dawley (SD) rats were randomly divided into three groups : Sham , SCI , and SNES. Electrical stimulation parameters were 1 ms pulse width and 100 Hz , with 20 mins each time , once a day for 21 days. The motor function was assessed by Basso⁃Beattie⁃Bresnahan (BBB) locomotor function scale , and the action potential conduction was detected by electrophysiology. Hematoxy⁃lin⁃eosin (HE) staining was used to observe the pathological changes in the spinal cord and the average cross⁃sectional area (CSA) of biceps femoris muscle fibers. The number of brain⁃derived neurotrophic factor (BDNF) and tropomyosin⁃related kinase B (TrkB) positive cells , relative mRNA and protein expression were analyzed by immunohistochemistry , reverse transcription polymerase chain reaction (RT PCR) and Western blot separately.@*Results@#On 21 d , the BBB score and average amplitude of action potential of SNES group were higher than those of SCI group , and the difference was statistically significant (P < 0. 05) . Compared with SCI group , the pathological injury of spinal cord tissue in SNES group was significantly improved , and the average CSA of biceps femoris muscles had a statistical difference (P < 0. 05) . The number of BDNF and TrkB positive cells in SNES group was higher than that in SCI group , and there were statistical differences (P < 0. 05) . The relative mRNA and protein expressions of BDNF and TrkB in SNES group were higher than those in SCI group , with statistical differences ( P <0. 05) . The relative mRNA and protein expressions of BDNF and TrkB in SNES group were higher than those in SCI group , with statistical differences ( P <0. 05) . @*Conclusion @#These results show that SNES contributes to alleviating spinal cord tissue injury , promoting the recovery of motor function and delaying the atrophy of muscles below the injury level. The possible mechanism is related to the increased expression of BDNF⁃TrkB proteins.

Extract Promotes Neurogenesis in the Hippocampal Dentate Gyrus of the Adult Mouse through Increasing Expressions of Brain-Derived Neurotrophic Factor and Tropomyosin-Related Kinase B / 中华医学杂志(英文版)

<p><b>Background</b>Glehnia littoralis has been used for traditional Asian medicine, which has diverse therapeutic activities. However, studies regarding neurogenic effects of G. littoralis have not yet been considered. Therefore, in this study, we examined effects of G. littoralis extract on cell proliferation, neuroblast differentiation, and the maturation of newborn neurons in the hippocampus of adult mice.</p><p><b>Methods</b>A total of 39 male ICR mice (12 weeks old) were randomly assigned to vehicle-treated and 100 and 200 mg/kg G. littoralis extract-treated groups (n = 13 in each group). Vehicle and G. littoralis extract were orally administrated for 28 days. To examine neurogenic effects of G. littoralis extract, we performed immunohistochemistry for 5-bromo-2-deoxyuridine (BrdU, an indicator for cell proliferation) and doublecortin (DCX, an immature neuronal marker) and double immunofluorescence staining for BrdU and neuronal nuclear antigen (NeuN, a mature neuronal marker). In addition, we examined expressional changes of brain-derived neurotrophic factor (BDNF) and its major receptor tropomyosin-related kinase B (TrkB) using Western blotting analysis.</p><p><b>Results</b>Treatment with 200 mg/kg, not 100 mg/kg, significantly increased number of BrdU-immunoreactive () and DCX cells (48.0 ± 3.1 and 72.0 ± 3.8 cells/section, respectively) in the subgranular zone (SGZ) of the dentate gyrus (DG) and BrdU/NeuN cells (17.0 ± 1.5 cells/section) in the granule cell layer as well as in the SGZ. In addition, protein levels of BDNF and TrkB (about 232% and 244% of the vehicle-treated group, respectively) were significantly increased in the DG of the mice treated with 200 mg/kg of G. littoralis extract.</p><p><b>Conclusion</b>G. littoralis extract promots cell proliferation, neuroblast differentiation, and neuronal maturation in the hippocampal DG, and neurogenic effects might be closely related to increases of BDNF and TrkB proteins by G. littoralis extract treatment.</p>

Expressions of brain derived neurotrophic factor and tropomyosin-related kinase B and their significances in rats with early brain injury after subarachnoid hemorrhage / 中华神经医学杂志

Objective To observe the expressions of brain derived neurotrophic factor (BDNF) and tropomyosin-related kinase B (TrkB) in rats with early brain injury (EBI) after subarachnoid hemorrhage,and study the neuroprotective effects of BDNF and TrkB on EBI.Methods Male Sprague-Dawley rats (n=56),weighing 280-320 g,were randomly divided into sham-operated group and SAH group;SAH models were established by endovascular perforation ofinternal carotid artery.At 24 and 72 h after modeling,neurological scale scores were recorded;brain water content was measured;immunohistochemical staining and ELISA were used to observe the dynamical expressions of BDNF and TrkB in the brain.Results At 24 and 72 h after modeling,the neurological function scores and brain water content of SAH rats were higher than those of sham-operated group.The expression scores of BDNF in the SAH rats were 1.33±0.52 and 1.67±0.52,and the expression levels were (12.11±0.44) mg/mL and (15.82±0.89) mg/mL;the expression scores of TrkB were 1.17±0.75 and 2.00±0.00,and the expression levels were (18.89±0.38) mg/mL and (25.18±0.68) mg/mL.The expression scores of BDNF in the sham-operated group were 0.33±0.52 and 0.17±0.41,and the expression levels of BDNF in the sham-operated group was (4.92±0.16) mg/mL and (4.93±0.20) mg/mL;the expression scores of TrkB were 0.17±0.41 and 0.33±0.52,and the expression levels were (8.52±0.41) mg/mL and (8.08±0.34) mg/mL.There were significant differences in BDNF and TrkB expressions between the two groups at 24 and 72 h after modeling (P＜0.05).Conclusion The expressions of BDNF and TrkB increase significantly after SAH,and BDNF and TrkB play protective effect on EBI after SAH.