The neuroprotective effects of Reg-2 following spinal cord transection injury

Role of C16, angiopoietin-1 and regeneration gene protein 2 in attenuating inflammation in an experimental rat model of autoimmune encephalomyelitis

Multiple sclerosis (MS) is a chronic neurological disorder that affects the central nervous system (CNS), and results in CNS inflammation and damage to myelin. In this study, we examined the possible synergistic effects of C16, angiopoietin-1 (Ang-1) and regeneration gene protein 2 (Reg-2) in alleviating inflammation in an acute experimental autoimmune encephalomyelitis (EAE) model. We employed multiple histological, morphological and iconographic assays to examine the effect of those drugs on disease onset, clinical scores and behavioral deficits. Our results demonstrated that triple combination therapy was more efficient than the monotherapy in EAE treatment. The triple therapy significantly delayed the onset of motor symptoms, reduced disease severity, attenuated inflammatory cell infiltration and suppressed the secretion of proinflammatory cytokines. Additionally, treatment increased anti-inflammatory cytokines expression, inhibited reactive astrocytes proliferation, reduced demyelination and axonal loss, and finally reduced the neural death. Specifically, Reg-2 administration rescued oligodendrocytes and neuronal axons mainly by direct neurotrophic effects, while C16+Ang-1 (C+A) mainly improved the inflammatory milieu. In conclusion, our study suggests a possible synergistic effect through targeting a variety of pathways in relieving the clinical symptoms of inflammation in acute EAE model. Therefore, using molecules that target different molecular pathways can be beneficial for exploring novel therapeutic approaches for MS treatment.

Reg-2, A Downstream Signaling Protein in the Ciliary Neurotrophic Factor Survival Pathway, Alleviates Experimental Autoimmune Encephalomyelitis

Ciliary neurotrophic factor (CNTF), originally described as a neurocytokine that could support the survival of neurons, has been recently found to alleviate demyelination, prevent axon loss, and improve functional recovery in a rat model of acute experimental autoimmune encephalomyelitis (EAE). However, poor penetration into the brain parenchyma and unfavorable side effects limit the utility of CNTF. Here, we evaluated the therapeutic potential of a protein downstream of CNTF, regeneration gene protein 2 (Reg-2). Using multiple morphological, molecular biology, and electrophysiological methods to assess neuroinflammation, axonal loss, demyelination, and functional impairment, we observed that Reg-2 and CNTF exert similar effects in the acute phase of EAE. Both treatments attenuated axonal loss and demyelination, improved neuronal survival, and produced functional improvement. With a smaller molecular weight and improved penetration into the brain parenchyma, Reg-2 may be a useful substitute for CNTF therapy in EAE and multiple sclerosis (MS).

Mesenchymal stem cells secrete brain-derived neurotrophic factor and promote retinal ganglion cell survival after traumatic optic neuropathy

OBJECTIVE

The study aimed to investigate whether intravitreal injection of mesenchymal stem cells (MSCs) cultivated in vitro could increase the number of survived retinal ganglion cells (RGCs) after traumatic optic neuropathy and sought to identify potential mechanisms underlying such growth.

METHODS

The right eye of 24 cats in the MSC transplantation group accepted intravitreal injection of MSCs, and the other 24 cats in the phosphate buffer (PBS) control group received isotonic saline after traumatic optic neuropathy. The RGCs' survival rate in separated retinal and brain-derived neurotrophic factor (BDNF) expression were observed by Dil labeling and Enzyme-Linked Immuno Sorbent Assay (ELISA), respectively, at 3, 7, 14, and 28 days after transplantation.

RESULTS

Quantitative analysis showed that RGCs were significantly attenuated at 3, 7, 14, and 28 days after transplantation in both areas of the retina (peripheral, P7d = 0.0011, P14d < 0.001, P28d < 0.001; central, P3d = 0.0437, P7d = 0.0067, P14d < 0.001, P28d < 0.001). Mean density of RGCs in the MSC transplantation group was significantly higher than that of the PBS control group after 14 days of treatment (P < 0.001). The homogenates BDNF (hBDNF) in the MSC transplantation group was obviously higher than that in the PBS control group at 14 and 28 days (P < 0.05).

CONCLUSIONS

The MSCs transplanted into the retina of cats can slow down RGC apoptosis and steadily express BDNF. The MSC-mediated neuroprotection after optic nerve injury may be related to BNDF.

The effect of spinal cord injury on the neurochemical properties of vagal sensory neurons

The vagus nerve is composed primarily of nonmyelinated sensory neurons whose cell bodies are located in the nodose ganglion (NG). The vagus has widespread projections that supply most visceral organs, including the bladder. Because of its nonspinal route, the vagus nerve itself is not directly damaged from spinal cord injury (SCI). Because most viscera, including bladder, are dually innervated by spinal and vagal sensory neurons, an impact of SCI on the sensory component of vagal circuitry may contribute to post-SCI visceral pathologies. To determine whether SCI, in male Wistar rats, might impact neurochemical characteristics of NG neurons, immunohistochemical assessments were performed for P2X3 receptor expression, isolectin B4 (IB4) binding, and substance P expression, three known injury-responsive markers in sensory neuronal subpopulations. In addition to examining the overall population of NG neurons, those innervating the urinary bladder also were assessed separately. All three of the molecular markers were represented in the NG from noninjured animals, with the majority of the neurons binding IB4. In the chronically injured rats, there was a significant increase in the number of NG neurons expressing P2X3 and a significant decrease in the number binding IB4 compared with noninjured animals, a finding that held true also for the bladder-innervating population. Overall, these results indicate that vagal afferents, including those innervating the bladder, display neurochemical plasticity post-SCI that may have implications for visceral homeostatic mechanisms and nociceptive signaling.

Allografts of the acellular sciatic nerve and brain-derived neurotrophic factor repair spinal cord injury in adult rats

OBJECTIVE

We aimed to investigate whether an innovative growth factor-laden scaffold composed of acellular sciatic nerve (ASN) and brain-derived neurotrophic factor (BDNF) could promote axonal regeneration and functional recovery after spinal cord injury (SCI).

METHODS

Following complete transection at the thoracic level (T9), we immediately transplanted the grafts between the stumps of the severed spinal cords. We evaluated the functional recovery of the hindlimbs of the operated rats using the BBB locomotor rating scale system every week. Eight weeks after surgery, axonal regeneration was examined using the fluorogold (FG) retrograde tracing method. Electrophysiological analysis was carried out to evaluate the improvement in the neuronal circuits. Immunohistochemistry was employed to identify local injuries and recovery.

RESULTS

The results of the Basso-Beattie-Bresnahan (BBB) scale indicated that there was no significant difference between the individual groups. The FG retrograde tracing and electrophysiological analyses indicated that the transplantation of ASN-BDNF provided a permissive environment to support neuron regeneration.

CONCLUSION

The ASN-BDNF transplantation provided a promising therapeutic approach to promote axonal regeneration and recovery after SCI, and can be used as part of a combinatory treatment strategy for SCI management.

Development of the human corpus striatum and the presence of nNOS and 5-HT2A receptors

This study focussed on the development of the corpus striatum in the fetus, using silver impregnation and immunohistochemistry. For the latter, we looked for nNOS positive cells and 5-HT(2A) receptors positive cells in the corpus striatum during development. During the initial formation of the corpus striatum, there was migration cells of the ganglionic eminence toward the putamen by 15-17 weeks of gestation. Process formation in the neurons started by week 17 and became very complex before term (31/32 weeks of gestation). By 25-27 gestational weeks, the globus pallidus already had two parts and the corpus striatum was similar to the adult in configuration. The nNOS positive cells appeared early (21-23 weeks in gestation) while 5-HT(2A) receptors positive cells were not observed until 31/32 weeks gestation. The number of positive cells in both groups was relatively small. It is anticipated that further developmental changes would occur in the postnatal/neonatal phases.

Anti-neuroinflammatory and neurotrophic effects of combined therapy with annexin II and Reg-2 on injured spinal cord

The present study was designed to investigate the neuroprotective effects of Ca(2+)-dependent phospholipid-binding protein annexin II and a secreted protein Reg-2 (regeneration gene protein 2) in spinal cord injury (SCI) model produced by contusion SCI at T(9) using the weight drop method. The agents were delivered intrathecally with Alzet miniosmotic pumps. We found that annexin II and Reg-2 remarkably reduced neuronal death, attenuated tissue damage and alleviated detrimental inflammation in vivo; meanwhile, a significant increase in white matter sparing and myelination area was observed. The propriospinal axons and long-distance supraspinal pathways were protected by the treatments as revealed by retrograde tracing. Basso Beattie Bresnahan locomotor rating scores also revealed a measurable behavioral improvement. However, no evident behavioral improvements in locomotor performance were achieved by the combined treatment with annexin II and Reg-2, compared with the separate treatment with annexin II and Reg-2.