PLGA-PEG-PLGA hydrogel with NEP1-40 promotes the functional recovery of brachial plexus root avulsion in adult rats

Adult brachial plexus root avulsion can cause serious damage to nerve tissue and impair axonal regeneration, making the recovery of nerve function difficult. Nogo-A extracellular peptide residues 1-40 (NEP1-40) promote axonal regeneration by inhibiting the Nogo-66 receptor (NgR1), and poly (D, L-lactide-co-glycolide)-poly (ethylene glycol)-poly (D, L-lactide-co-glycolide) (PLGA-PEG-PLGA) hydrogel can be used to fill in tissue defects and concurrently function to sustain the release of NEP1-40. In this study, we established an adult rat model of brachial plexus nerve root avulsion injury and conducted nerve root replantation. PLGA-PEG-PLGA hydrogel combined with NEP1-40 was used to promote nerve regeneration and functional recovery in this rat model. Our results demonstrated that functional recovery was enhanced, and the survival rate of spinal anterior horn motoneurons was higher in rats that received a combination of PLGA-PEG-PLGA hydrogel and NEP1-40 than in those receiving other treatments. The combined therapy also significantly increased the number of fluorescent retrogradely labeled neurons, muscle fiber diameter, and motor endplate area of the biceps brachii. In conclusion, this study demonstrates that the effects of PLGA-PEG-PLGA hydrogel combined with NEP1-40 are superior to those of other therapies used to treat brachial plexus nerve root avulsion injury. Therefore, future studies should investigate the potential of PLGA-PEG-PLGA hydrogel as a primary treatment for brachial plexus root avulsion.

Brachial plexus injury in the child

Obstetric brachial plexus palsy (OBPP) was first described by the Scottish obstetrician William Smellie in 1779 who described, in a newborn, a case of unilateral arm paralysis which rapidly recovered. He attributed this palsy to compression of the axillary nerve against the humerus, probably wrongly in light of subsequent knowledge. The main risk factor for OBPP is high birth weight (>4000 g) and intrapartum shoulder dystocia causing traction on the brachial plexus. It has been demonstrated in cadaveric models that traction on the arm with the neck laterally flexed in the opposite direction causes rupture or avulsion of the brachial plexus. Upper roots are more likely to rupture due to strong ligamentous attachment to the spine whereas the lower roots are more likely to be avulsed. For unknown reasons, however, in the rare circumstance of small babies born breech, upper root avulsion is common. Other risk factors for OBPP include a previous child affected, prolonged labour, instrumented delivery, and multiparity, although each of these may be a surrogate for large birth weight.

Additive value of magnetic resonance neurography in diagnosis of brachial plexopathy: a cross-section descriptive study

Background Management of brachial plexopathy requires proper localization of the site and nature of nerve injury. Nerve conduction studies and electrophysiological studies (ED) are crucial when diagnosing brachial neuropathy but these do not determine the actual site of the lesion. Conventional MRI has been used to evaluate the brachial plexus. Still, it carried the disadvantage of the inability to provide multi-planar images that depict the entire length of the neural plexus .It might be difficult to differentiate the brachial plexus nerves from adjacent vascular structures. Magnetic resonance neurography (MRN) is an innovative imaging technique for direct imaging of the spinal nerves. Our study aims to detect the additive role of MRN in the diagnosis of brachial plexopathy over ED. Forty cases of clinically suspected and proved by clinical examination and ED—traumatic (N = 30) and non-traumatic (N = 10)—were included in our study. We compared MRN finding with results of clinical examination and ED. Results MRN findings showed that the root was involved in 80% of cases, trunks in 70% of cases affecting the middle trunk in 40% of cases, the middle and posterior cord in 25%, lateral cord in 50%, and terminal branches on 10% of cases. Ten percent of cases were normal according to MRN, and 90% had abnormal findings in the form of preganglionic nerve root avulsion in 30% of cases, mild perineural edema surrounding C6/7 nerve roots in 20%, lower brachial trunk high signal in 10%, complicated with pseudo meningocele in 20%, and with increased shoulder muscle T2 signal intensity with muscle atrophy in 10%. There were minimal differences between clinical examination finding and MRN findings, with very good agreement between electromyography and nerve conduction (p value < 0.05, with sensitivity and specificity values of 94.44% and 100%, respectively). Conclusion MRN is important in differentiating different types of nerve injuries, nerve root avulsion, and nerve edema, playing an important role in differentiating the site of nerve injury, both preganglionic or postganglionic and planning for treatment of the cause of nerve injury, either medical or surgical.

Arthroscopic incidence of lateral meniscal root avulsion in patients with anterior cruciate ligament injury

Background To arthroscopically evaluate the incidence of lateral meniscal root avulsion (LMRA) and associated intra-articular injuries in patients undergoing anterior cruciate ligament (ACL) reconstruction. Materials and Methods From April 2014 to March 2017, 532 consecutive patients were diagnosed as having an ACL injury and underwent arthroscopic ACL reconstruction. The diagnosis of LMRA was made arthroscopically. The effects of gender, activity, grade of laxity, time from injury, and concomitant meniscal lesions were analyzed. Results Among 532 patients, 497 (93.4%) underwent primary ACL reconstruction and 35 (6.5%) underwent revision procedures. 383 were acute or subacute injuries (less than 6 months from injury to surgery) and 149 chronic (more than 6 months). Average age was 30.4 years (DS: ± 11.04); there were 422 (79.3%) males and 110 (20.6%) females. A LMRA associated with the ACL injury was detected in 72 cases (13.5%), with a significant prevalence observed in males ($${\chi ^2}$$ χ 2 = 4.65; P = 0.031, statistically significant). In the 149 patients with a chronic injury, 27 patients had LMRA (18.1%), while 45 of the 383 patients with an acute or subacute injury had LMRA (11.7%). There was a tendency, albeit not significant ($${\chi ^2}$$ χ 2 = 3.721; P = 0.054), for the prevalence to increase with time since the initial ACL injury. LMRA was significantly associated ($${\chi ^2}$$ χ 2 = 7.81; P = 0.006) with a meniscocapsular tear of the posterior horn of the medial meniscus (ramp lesion). No other significant associations, such as with severity of A-P translation (as measured by KT-2000) or activity level, were detected. Conclusion LMRA is a relatively common injury associated with both acute and chronic ACL tears. A relatively high incidence in cases of chronic ACL insufficiency suggests that LMRAs do not heal spontaneously or that they may appear with time, even when absent at the time of the initial injury. Level of evidence Level III, cross-sectional study.

(-)-Epigallocatechin Gallate Attenuates Spinal Motoneuron Death Induced by Brachial Plexus Root Avulsion in Rats

BackgroundRecent studies have indicated that epigallocatechin gallate (EGCG) benefits a variety of neurological insults. This study was performed to investigate the neuroprotective effect of EGCG after brachial plexus root avulsion in rats. Methods One hundred twenty rats were randomized into the following three groups: an EGCG group, an Avulsion group, and a Sham group. EGCG (100 mg/kg, i.p.) or normal saline was administered to rats immediately following the injuries. The treatment was continued from day 1 to day 7, and the animals were sacrificed on days 3, 7, 14 and 28 for Nissl staining, immunohistochemistry and western blot analysis.Results We determined that EGCG significantly increased the survival ratio of motoneurons and inhibited the cell apoptosis. The level of phospho-c-jun was reduced at 3d and 7d after the injury.Conclusions Our results indicated that motoneurons were protected by EGCG against the cell death induced by brachial plexus root avulsion,and this effect was correlated with inhibiting c-jun phosphorylation.

Pain Relief Dependent on IL-17–CD4+ T Cell–β-Endorphin Axis in Rat Model of Brachial Plexus Root Avulsion After Electroacupuncture Therapy

Background and purposeNeuropathic pain is the typical symptom of brachial plexus root avulsion (BPRA), and no effective therapy is currently available. Electroacupuncture (EA), as a complementary and alternative therapy, plays a critical role in the management of pain-associated diseases. In the present study, we aimed to reveal the peripheral immunological mechanism of EA in relieving the pain of BPRA through the IL-17–CD4+ T lymphocyte–β-endorphin axis.MethodsAfter receiving repeated EA treatment, the pain of BPRA in rats along with the expressions of a range of neurotransmitters, the contents of inflammatory cytokines, and the population of lymphocytes associated were investigated. CD4+ T lymphocytes were either isolated or depleted with anti-CD4 monoclonal antibody. The titers of IL-17A, interferon-γ (IFN-γ), and β-endorphin were examined. The markers of T lymphocytes, myeloid-derived suppressor cells (MDSCs), dendritic cells (DCs), macrophages, and natural killer (NK) cells were assessed. The activation of the nuclear transcription factor κB (NF-κB) signaling pathway was tested.ResultsThe pain of BPRA was significantly relieved, and the amount of CD4+ T lymphocytes was increased after EA treatment. The release of β-endorphin was up-regulated with the up-regulation of IL-17A in CD4+ T lymphocytes. The titer of IL-17A was enhanced, leading to an activated NF-κB signaling pathway. The release of β-endorphin and the analgesic effect were almost completely abolished when CD4+ T lymphocytes were depleted.ConclusionWe, for the first time, showed that the neuropathic pain caused by BPRA was effectively relieved by EA treatment via IL-17–CD4+ T lymphocyte–β-endorphin mediated peripheral analgesic effect, providing scientific support for EA clinical application.