Cerebrospinal fluid-contacting neurons in the regenerating spinal cord of lizards and amphibians are likely mechanoreceptors

Effectiveness of craniosacral therapy in the human suboccipital region on hamstring muscle: A meta-analysis based on current evidence

BACKGROUND

Craniosacral therapy (CST) has remained controversial in the treatment of musculoskeletal disorders. To our knowledge, there is no larger sample size of research to demonstrate the effectiveness of craniosacral therapy in the human suboccipital region on hamstring muscle.

METHODS

To study whether the CST in the human suboccipital region could have a remote effect on the flexibility of the hamstring muscles, the Cochrane Library, Medline/Pubmed, CNKI, Embase, and Google Scholar were searched. Clinical trials assessing the effects of CST in short hamstring syndrome patients were eligible. Mean differences (MD) and 95% confidence intervals (CI) were calculated for the straight leg raise test (primary outcomes). The quality of the included studies was assessed using the Newcastle-Ottawa Scale. RevMan 5.3 software was used for data analysis.

RESULTS

Five controlled trials with a total of 238 participants were included. CST could effectively relieve the symptoms of short hamstring syndrome patients [the overall MD -9.47, 95% confidence interval (CI) -15.82 to -3.12, P < .000001]. The CST was better than the proprioceptive neuromuscular facilitation technique (MD 3.09, 95% CI 1.48-4.70, P = .0002). Sensitivity analysis shows that the frequency of treatment and who did the experiment might be the main sources of impact results.

CONCLUSION

CST could change the flexibility of the hamstring muscles. CST had a better curative effect when compared to proprioceptive neuromuscular facilitation technique on the hamstring muscles.

Radial Glia and Neuronal-like Ependymal Cells Are Present within the Spinal Cord of the Trunk (Body) in the Leopard Gecko (Eublepharis macularius)

As is the case for many lizards, leopard geckos (Eublepharis macularius) can self-detach a portion of their tail to escape predation, and then regenerate a replacement complete with a spinal cord. Previous research has shown that endogenous populations of neural stem/progenitor cells (NSPCs) reside within the spinal cord of the original tail. In response to tail loss, these NSPCs are activated and contribute to regeneration. Here, we investigate whether similar populations of NSPCs are found within the spinal cord of the trunk (body). Using a long-duration 5-bromo-2′-deoxyuridine pulse-chase experiment, we determined that a population of cells within the ependymal layer are label-retaining following a 20-week chase. Tail loss does not significantly alter rates of ependymal cell proliferation within the trunk spinal cord. Ependymal cells of the trunk spinal cord express SOX2 and represent at least two distinct cell populations: radial glial-like (glial fibrillary acidic protein- and Vimentin-expressing) cells; and neuronal-like (HuCD-expressing) cells. Taken together, these data demonstrate that NSPCs of the trunk spinal cord closely resemble those of the tail and support the use of the tail spinal cord as a less invasive proxy for body spinal cord injury investigations.

Spinal ganglia and peripheral nerves innervating the regenerating tail and muscles of lizards

The present review summarizes available information on the contribution of regenerating nerves to the process of regeneration in the tail of lizards. From the last three segments of the spinal cord and ganglia proximal to the regenerating tail, motor, sensory somatic and autonomous nerves regenerate and richly innervate the growing blastema. However, experimental studies have indicated that peripheral nerves are not essential for stimulating the regeneration of the tail that instead is mainly sustained by the interaction of the apical ependyma with the wound epidermis. Ganglion neurons innervating the regenerating blastema increase their size and some satellite cells multiply but no ganglion neurons are regenerated. Numerous Schwann cells proliferate to keep pace with nerve regeneration, and they form myelin starting from 3 to 4 weeks of tail regeneration. The hypertrophic ganglion neurons synthesize growth factors and signaling proteins such as FGFs and Wnts that are transported into the regenerating blastema through the regenerating nerves. Nerves form synaptic-like contacts with mesenchymal cells or fibroblasts at the tip of the regenerating blastema but not synaptic boutons. These terminals may discharge stimulating factors that favor cell proliferation but this is not experimentally demonstrated. Most of the innervation is directed to differentiating muscles where nerve endings form cholinergic motor-plates. Transcriptome data on the regenerating blastema-cone detect up-regulation of various genes coding for ionic channels, neurotransmitter receptors and signaling proteins. The latter suggests that the neurotrophic stimulation may control cell proliferation but is most directed to the functionality of regenerating muscles.

Growth associated protein 43 and neurofilament immunolabeling in the transected lumbar spinal cord of lizard indicates limited axonal regeneration

Previous cytological studies on the transected lumbar spinal cord of lizards have shown the presence of differentiating glial cells, few neurons and axons in the bridge region between the proximal and distal stumps of the spinal cord in some cases. A limited number of axons (20–50) can cross the bridge and re-connect the caudal stump of the spinal cord with small neurons located in the rostral stump of the spinal cord. This axonal regeneration appears to be related to the recovery of hind-limb movements after initial paralysis. The present study extends previous studies and shows that after transection of the lumbar spinal cord in lizards, a glial-connective tissue bridge that reconnects the rostral and caudal stumps of the interrupted spinal cord is formed at 11–34 days post-injury. Following an initial paralysis some recovery of hindlimb movements occurs within 1–3 months post-injury. Immunohistochemical and ultrastructural analysis for a growth associated protein 43 (GAP-43) of 48–50 kDa shows that sparse GAP-43 positive axons are present in the proximal stump of the spinal cord but their number decreased in the bridge at 11–34 days post-transection. Few immunolabeled axons with a neurofilament protein of 200–220 kDa were seen in the bridge at 11–22 days post-transection but their number increased at 34 days and 3 months post-amputation in lizards that have recovered some hindlimb movements. Numerous neurons in the rostral and caudal stumps of the spinal cord were also labeled for GAP43, a cytoplasmic protein that is trans-located into their axonal growth cones. This indicates that GAP-43 biosynthesis is related to axonal regeneration and sprouting from neurons that were damaged by the transection. Taken together, previous studies that utilized tract-tracing technique to label the present observations confirm that a limited axonal re-connection of the transected spinal cord occurs 1–3 months post-injury in lizards. The few regenerating-sprouting axons within the bridge reconnect the caudal with the rostral stumps of the spinal cord, and likely contribute to activate the neural circuits that sustain the limited but important recovery of hind-limb movements after initial paralysis. The surgical procedures utilized in the study followed the regulations on animal care and experimental procedures under the Italian Guidelines (art. 5, DL 116/92).

Cerebrospinal fluid-contacting neurons affect the expression of endogenous neural progenitor cells and the recovery of neural function after spinal cord injury

OBJECTIVE

To explore the relationship between cerebrospinal fluid-contacting neurons (CSF-cNs) and endogenous neural progenitor cells (ENPCs) and whether CSF-cNs are involved in nerve repair after spinal cord injury (SCI).

METHODS

Cholera toxin B-horseradish peroxidase complex (CB-HRP) and cholera toxin B conjugated with saporin (CB-SAP) were injected into the lateral ventricles of spinal cord injured rats to mark and destroy the CSF-cNs. Then the rats in the experimental group were injured by SCI. Observe the content and co-expression of CSF-cNs and ENPCs in rats of each group, and observe the recovery of motor function after SCI in each group.

RESULTS

After the destruction of CSF-cNs, the number of ENPCs decreased significantly in the long term after the surgery, and the recovery of motor function also deteriorated as compared to the group with intact CSF-cNs. Meanwhile some cells in the spinal cord express both the biological marker of CSF-cNs and ENPCs.

CONCLUSION

This study shows that the population of ENPCs and motor function recovery in SCI rats declined after the destruction of CSF-cNs, suggesting that CSF-cNs affect the ENPCs population and may be involved in the recovery of neural function after SCI.