M1-type microglia can induce astrocytes to deposit chondroitin sulfate proteoglycan after spinal cord injury.

After spinal cord injury (SCI), astrocytes gradually migrate to and surround the lesion, depositing chondroitin sulfate proteoglycan-rich extracellular matrix and forming astrocytic scar, which limits the spread of inflammation but hinders axon regeneration. Meanwhile, microglia gradually accumulate at the lesion border to form microglial scar and can polarize to generate a pro-inflammatory M1 phenotype or an anti-inflammatory M2 phenotype. However, the effect of microglia polarization on astrocytes is unclear. Here, we found that both microglia (CX3CR1+) and astrocytes (GFAP+) gathered at the lesion border at 14 days post-injury (dpi). The microglia accumulated along the inner border of and in direct contact with the astrocytes. M1-type microglia (iNOS+CX3CR1+) were primarily observed at 3 and 7 dpi, while M2-type microglia (Arg1+CX3CR1+) were present at larger numbers at 7 and 14 dpi. Transforming growth factor-ß1 (TGFß1) was highly expressed in M1 microglia in vitro, consistent with strong expression of TGFß1 by microglia in vivo at 3 and 7 dpi, when they primarily exhibited an M1 phenotype. Furthermore, conditioned media from M1-type microglia induced astrocytes to secrete chondroitin sulfate proteoglycan in vitro. This effect was eliminated by knocking down sex-determining region Y-box 9 (SOX9) in astrocytes and could not be reversed by treatment with TGFß1. Taken together, our results suggest that microglia undergo M1 polarization and express high levels of TGFß1 at 3 and 7 dpi, and that M1-type microglia induce astrocytes to deposit chondroitin sulfate proteoglycan via the TGFß1/SOX9 pathway. The study was approved by the Institutional Animal Care and Use Committee of Anhui Medical University, China (approval No. LLSC20160052) on March 1, 2016.

Transcranial direct current stimulation treated by multilead brain reflex instrument accelerates neural functional recovery in a rat model of stroke.

PURPOSE: Clinical research suggests that transcranial direct current stimulation (tDCS) at bilateral supraorbital foramen and inferior orbital rim and nose intersections may facilitate rehabilitation after stroke. However, the underlying neurobiological mechanisms of tDCS remain poorly understood, impeding its clinical application. Here, we investigated the effect of tDCS applied after stroke on neural cells. MATERIALS AND METHODS: Middle cerebral arterial occlusion (MCAO) reperfusion was induced in rats. Animals with comparable infarcts were randomly divided into MCAO group and MCAO + tDCS group. Recovery of neurological function was assessed behaviorally by modified neurological severity score (mNSS). Ischemic tissue damage verified histologically by TTC and HE staining. Immunohistochemical staining, real-time qPCR, and western blot were applied to determine the changes of neural cells in ischemic brains. RESULTS: The results reveal that tDCS treated by multilead brain reflex instrument can promote the recovery of neurological function, remarkably reduce cerebral infarct volume, promote brain tissue rehabilitation, and can effectively inhibit astrocytosis and enhance neuronal survival and synaptic function in ischemic brains. CONCULSIONS: Our study suggests that tDCS treated by multilead brain reflex instrument could be prospectively developed into a clinical treatment modality.

TrkA regulates the regenerative capacity of bone marrow stromal stem cells in nerve grafts.

We previously demonstrated that overexpression of tropomyosin receptor kinase A (TrkA) promotes the survival and Schwann cell-like differentiation of bone marrow stromal stem cells in nerve grafts, thereby enhancing the regeneration and functional recovery of the peripheral nerve. In the present study, we investigated the molecular mechanisms underlying the neuroprotective effects of TrkA in bone marrow stromal stem cells seeded into nerve grafts. Bone marrow stromal stem cells from Sprague-Dawley rats were infected with recombinant lentivirus vector expressing rat TrkA, TrkA-shRNA or the respective control. The cells were then seeded into allogeneic rat acellular nerve allografts for bridging a 1-cm right sciatic nerve defect. Then, 8 weeks after surgery, hematoxylin and eosin staining showed that compared with the control groups, the cells and fibers in the TrkA overexpressing group were more densely and uniformly arranged, whereas they were relatively sparse and arranged in a disordered manner in the TrkA-shRNA group. Western blot assay showed that compared with the control groups, the TrkA overexpressing group had higher expression of the myelin marker, myelin basic protein and the axonal marker neurofilament 200. The TrkA overexpressing group also had higher levels of various signaling molecules, including TrkA, pTrkA (Tyr490), extracellular signal-regulated kinases 1/2 (Erk1/2), pErk1/2 (Thr202/Tyr204), and the anti-apoptotic proteins Bcl-2 and Bcl-xL. In contrast, these proteins were downregulated, while the pro-apoptotic factors Bax and Bad were upregulated, in the TrkA-shRNA group. The levels of the TrkA effectors Akt and pAkt (Ser473) were not different among the groups. These results suggest that TrkA enhances the survival and regenerative capacity of bone marrow stromal stem cells through upregulation of the Erk/Bcl-2 pathway. All procedures were approved by the Animal Ethical and Welfare Committee of Shenzhen University, China in December 2014 (approval No. AEWC-2014-001219).

Accessory Anteromedial Portal may not Provide Clinically Superior Results Compared with the Anteromedial Portal in Anterior Cruciate Ligament Reconstruction.

Techniques using the anteromedial portal (AMP) and accessory anteromedial portal (AAMP) are commonly used in anterior cruciate ligament (ACL) reconstruction. The aim of this study was to investigate the radiological and clinical outcomes of arthroscopic single-bundle ACL reconstruction using the AMP or AAMP technique to drill the femoral tunnel. The records of 157 patients who underwent single-bundle ACL reconstruction using the AMP or AAMP technique between 2011 and 2015 were reviewed. The femoral tunnel clock-face position and femoral tunnel and tibial tunnel anterior-posterior (AP) inclination angles were assessed on axial or AP magnetic resonance images. At last follow-up, the Lachman test and pivot-shift test were used to evaluate AP and rotational stability, respectively. The Lysholm knee scoring scale and the International Knee Documentation Committee (IKDC) form were used to evaluate clinical and functional results. No statistically significant differences were found between the groups in patient age, sex, follow-up period, or affected side distribution. The mean femoral tunnel inclination angle was 31.13 ± 8.06 degrees in the AMP group and 30.17 ± 9.02 degrees in the AAMP group (p = 0.513). The tibial tunnel inclination angle in the AMP group (16.28 ± 7.89 degrees) was not different from that in the AAMP group (13.70 ± 6.08 degrees). No significant differences were observed between the two groups in the Lachman test, pivot-shift test, Lysholm knee scoring scale, or IKDC scores. The AAMP technique was not clinically superior to the AMP technique in ACL reconstruction. This is a retrospective comparative study and its level of evidence is III.

Early results of the proximal femoral nail antirotation-Asia for intertrochanteric fractures in elderly Chinese patients.

OBJECTIVE: To report early efficacy and safety of the proximal femoral nail antirotation-Asia for intertrochanteric fractures in elderly Chinese patients. METHODS: This retrospective study was carried out in the Second Hospital of Anhui Medical University, Anhui, China between June 2009 and December 2012. A total of 108 patients with intertrochanteric fractures were available for the outcome analysis in the study. There were 62 female and 46 male patients with a mean age of 75 +/= 10 years. The stable group included 18 cases of 31 A1 fractures, the unstable group included 68 cases of 31 A2 fractures, and 22 cases of 31 A3 fractures. Follow-up evaluations were performed at 1, 3, 6, 9, and 12 months, and every year thereafter. RESULTS: During the average 29 +/= 9 months early follow-up period, 4 patients (4%) were lost, and 6 patients (6%) died within 6 months due to causes unrelated to the fracture. Fracture union occurred in all patients, 83 patients (85%) showed an excellent, or good outcome. The mean Harris Hip Score was 85.2 +/= 7.5 points. Mechanical failures, such as bending, or breaking of the implant were not seen, and cut-outs were not observed. CONCLUSION: The results suggest that proximal femoral nail antirotation-Asia is effective and safe in the treatment of inter-trochanteric fractures in elderly Chinese patients.