ObjectiveTo explore the effects of electroacupuncture at governor vessel or Jiaji acupoints on the activation of lumbar spinal cord neurons and the recovery of motor function in paralyzed hind limbs in rats with complete transection of spinal cord injury. MethodsTwenty adult female SD rats were selected. Among them， 15 rats underwent the complete transection of the 10th thoracic spinal cord and were randomly divided into the Control group， the electroacupuncture at governor vessel acupoints （GV） group and the electroacupuncture at Jiaji acupoints （JJ） group， with 5 rats in each group. The other 5 rats served as the Normal group. Electroacupuncture treatment was initiated 3 days after surgery in the GV and JJ groups and performed every other day. Basso-Beatti-Bresnahan （BBB） behavioral score was evaluated weekly. Eight weeks after the operation， cortical motor evoked potential （CMEP） detection was performed， followed by perfusion fixation， tissue harvest， frozen sectioning， and immunofluorescence staining experiments. Results① Both electroacupuncture treatments activated the expression of the excitatory marker c-Fos in L1 spinal cord neurons. The c-Fos⁺ activated neurons were mainly distributed in lamina Ⅳ， Ⅴ and Ⅶ of the L1 spinal cord， while no c-Fos⁺ neuron was observed in the Normal group and the Control group. The percentages of c-Fos⁺ neurons activated by electroacupuncture in the GV group and the JJ group were （10.23±0.15） % and （10.77±1.12） %， respectively， and there was no significant difference between the two electroacupuncture groups. ② vGluT1⁺ proprioceptive afferent nerve fibers were mainly distributed in the dorsal horn and lamina Ⅶ of intermediate zone of L1 spinal cord gray matter. In the dorsal horn of L1 spinal cord， the relative fluorescence intensity of vGluT1⁺ nerve fibers in the GV group and the JJ group were greater than that in the Control group， and that in the JJ group was greater than that in the GV group. In the lamina Ⅶ in intermediate zone of L1 spinal cord， where the central pattern generator （CPG） for hindlimb rhythmic movement is located， the relative fluorescence intensity of vGluT1⁺ nerve fibers in the GV group and the JJ group were significantly higher than that in the Control group， and the JJ group was also higher than the GV group； The lamina Ⅶ neurons innervated by vGluT1⁺ axon terminals were activated to express the excitatory marker c-Fos in the GV group and the JJ group. ③ The immunofluorescence staining results of acetylcholinesterase （ChAT） in the ventral horn of L4 spinal cord of each group showed that the number of surviving ChAT⁺ motor neurons in the GV group （19.1±3.4， P=0.000 2） and JJ group （19.0±2.9， P=0.000 2） were higher than that in the Control group （9.9±1.9）. ④ The quantitative analysis of the vGluT2⁺ excitatory axonal terminals， vGAT⁺ inhibitory axonal terminals， and the ratio of vGluT2⁺/vGAT⁺ axonal terminals ［reflecting the excitation/inhibition （E/I） balance of motor neurons］ innervating ChAT⁺ motor neurons in the ventral horn of the L4 spinal cord revealed that all three indices were significantly higher in the GV and JJ groups than in the Control group. Moreover， the E/I ratio of motor neurons in the two electroacupuncture groups gradually reached the same level as normal and showed no statistical difference from the Normal group. ⑤ The electrophysiological and behavioral detection results showed that compared with the Control group， the latencies of CMEP in the GV group and the JJ group shortened， while their amplitudes increased. The BBB score of paralyzed hindlimbs showed that after 8 weeks of treatment， the scores of both the GV group （4.25±1.26， P=0.023 4） and the JJ group （4.75±0.96， P=0.000 2） were higher than those of the Control group （1.80±1.30）， but there was no statistical difference between the two electroacupuncture groups. ConclusionElectroacupuncture at GV or JJ acupoints may promote the afferent of vGluT1⁺ proprioceptive nerve fibers into the spinal cord， indicating the possibility to activate CPG neurons in lamina Ⅶ of L1 spinal cord； facilitate the survival of motor neurons in the L4 spinal cord and restore their excitatory/inhibitory balance， improving the motor function of the paralyzed hindlimbs in rats.

In growing children, growth plate cartilage has limited self-repair ability upon fracture injury always leading to limb growth arrest. Interestingly, one type of fracture injuries within the growth plate achieve amazing self-healing, however, the mechanism is unclear. Using this type of fracture mouse model, we discovered the activation of Hedgehog (Hh) signaling in the injured growth plate, which could activate chondrocytes in growth plate and promote cartilage repair. Primary cilia are the central transduction mediator of Hh signaling. Notably, ciliary Hh-Smo-Gli signaling pathways were enriched in the growth plate during development. Moreover, chondrocytes in resting and proliferating zone were dynamically ciliated during growth plate repair. Furthermore, conditional deletion of the ciliary core gene Ift140 in cartilage disrupted cilia-mediated Hh signaling in growth plate. More importantly, activating ciliary Hh signaling by Smoothened agonist (SAG) significantly accelerated growth plate repair after injury. In sum, primary cilia mediate Hh signaling induced the activation of stem/progenitor chondrocytes and growth plate repair after fracture injury.
Mice ; Animals ; Hedgehog Proteins/genetics* ; Receptors, G-Protein-Coupled/metabolism* ; Cilia/metabolism* ; Cartilage/metabolism* ; Regeneration

Objective: To investigate the effect of endogenous iron accumulation onbone mass, intraosseous vessels and the effect of exogenous iron on endothelial cell activity. Methods: The mice were divided into control group (C57/BL6 mice without hepcidin knockout) and hepcidin-knockout group (10 mice in each group, 8 weeks old and weighing about 22 g). The mice in both groups were killed at the age of 16 weeks. Serum ferritin levels were measured by Enzyme-linked immunosorbent assay (ELISA), and iron accumulation in liver tissue was measured by Prussian blue staining, while femoral micro-structure was measured by micro-CT, and H-type vessel immunofluorescence staining was used to detect the number of H-vessels in bone. Cell experiments were divided into normal culture group (normal cell group) and intervention group (Fe group) with 200 μmol/L ammonium ferric citrate. Scratch test was used to detect the migration ability of vascular endothelial cells, and tube formation test was used to detect the function of vascular endothelial cells. The endothelial activity of vascular endothelial cells was detected by immunofluorescence. Results: The level of serum ferritin (318.30±12.53 ng/ml) in the hepcidin-knockout group was significantly higher than that in control group (109.60±4.66 ng/ml). The percentage of blue area of Prussian liver iron staining in the hepcidin-knockout group (80.80%±3.156%) was significantly higher than that in control group (20.94%±2.813%). Bone mineral density in the hepcidin-knockout group (0.044±0.002 mg/m³) was significantly higher than that in control group (0.131±0.008 mg/m³). The number of intraosseous blood vessels in the hepcidin-depleted mice (17.06%±1.060%) was significantly lower than that in control group (38.76%±4.576%). There were significant differences between the two groups in each index (t=-49.367,-13.788, 35.293, 6.165; all P < 0.05). The scratches of vascular endothelial cells in Fe group were reduced by 24.300%±1.849% after 24 hours of culture, which was significantly lower than that in normal group (39.060%±3.211%). The area of vascular endothelial cells in Fe group (0.035±0.003 mm²) was significantly lower than that in normal group (0.330±0.018 mm²). The EMCN positive cells of vascular endothelial cells in Fe group were significantly lower than those in normal group. The percentage of cell number (12.000%±3.462%) was significantly lower than that of normal cell group (0.035%±0.003%). There were significant differences in cell indices between the two groups (t=9.790, 18.929, 13.922; all P< 0.05). Conclusion Endogenous iron accumulation aggravated bone loss in mice, and the number of intraosseous blood vessels decreased significantly. Vascular endothelial cells were inhibited by iron intervention in migration, tube-formation and endothelial ability.