Abstract:Intellectual and scientific content of the study.
ABSTRACT PURPOSE:To evaluate a new model of intraoperative electromyographic (EMG) assessment of the tibial and fibular nerves, and its respectives motor units in rats.
METHODS:Eight Wistar rats underwent intraoperative EMG on both hind limbs at two different moments: week 0 and week 12.Supramaximal electrical stimulation applied on sciatic nerve, and compound muscle action potential recorded on the gastrocnemius muscle (GM) and the extensor digitorum longus mu… Show more
“…There is no telling if the electrical stimulus used in the preoperative period was supramaximal or if the intensity was maintained or increased during the experiment, which could cause current leakage and an abnormally high CMAP in response . (3) The stimulating and measuring electrodes were on opposite sides of the surgical field, however, no standardized distance was established between them, which could produce abnormal CMAP results or contamination of electrophysiological answers by branches of the sciatic, sural, tibia, or fibular nerves . (4) The author evaluates CMAP amplitude but not duration or latency, which are also important when considering nerve function.…”
Section: Discussionmentioning
confidence: 99%
“…The author also reported that distal motor and sensory axon counts were higher in polyethylene glycol‐treated rats. However, in addition to all the problems mentioned in the paragraph above about methodology used for the functional evaluation tests, the authors used female rats that undergo hormonal changes that alters neural regeneration …”
Section: Discussionmentioning
confidence: 99%
“…9 (3) The stimulating and measuring electrodes were on opposite sides of the surgical field, however, no standardized distance was established between them, which could produce abnormal CMAP 9 results or contamination of electrophysiological answers by branches of the sciatic, sural, tibia, or fibular nerves. 36 (4) The author evaluates CMAP amplitude but not duration or latency, which are also important when considering nerve function. Therefore, although the electrophysiological results obtained by Bittner et al 5 (2012) can be criticized, the behavioral tests demonstrate a significant improvement in neural regeneration in the long term (>60% regeneration in 12 weeks).…”
Section: Discussionmentioning
confidence: 99%
“…The author also reported that distal motor and sensory axon counts were higher in polyethylene glycoltreated rats. However, in addition to all the problems mentioned in the paragraph above about methodology used for the functional evaluation tests, 9,17,[34][35][36] the authors used female rats that undergo hormonal changes that alters neural regeneration. 42,43 Regarding histologic evaluation, there was no difference found in the total axonal count or in axonal density when comparing groups (Kruskal-Wallis test; P 5 .702; Figure 2; Table 2) as described by Bamba et al 41 Nonetheless, the mean axonal diameter of the groups that used the polyethylene glycol-fusion protocol (groups B and D) was increased (groups A and C; Bonferroni correction test; P .001; Figure 2; Table 2) showing that polyethylene glycol-fusion interfered with demyelination.…”
Section: Discussionmentioning
confidence: 99%
“…Salomone 40 (2013), using the same animal model with 1 surgical procedure only, describes a mortality rate of 8.3%. Regarding CMAPs, despite most authors claiming that the earlier the better, [34][35][36][37] the absence of statistical differences in the results of all the histologic and functional variables when we compare groups using only microsutures (group A vs group C; control groups), which is, up to today, the gold standard for neurotmesis, 34,37,39,44 in the third and sixth week after nerve severance (Mann-Whitney test; P .488 in both cases) leads us to the conclusion that regarding very severe nerve lesions, surgical intervention in feasible 24 or 72 hours after trauma with no consequences on the final outcome.…”
“…There is no telling if the electrical stimulus used in the preoperative period was supramaximal or if the intensity was maintained or increased during the experiment, which could cause current leakage and an abnormally high CMAP in response . (3) The stimulating and measuring electrodes were on opposite sides of the surgical field, however, no standardized distance was established between them, which could produce abnormal CMAP results or contamination of electrophysiological answers by branches of the sciatic, sural, tibia, or fibular nerves . (4) The author evaluates CMAP amplitude but not duration or latency, which are also important when considering nerve function.…”
Section: Discussionmentioning
confidence: 99%
“…The author also reported that distal motor and sensory axon counts were higher in polyethylene glycol‐treated rats. However, in addition to all the problems mentioned in the paragraph above about methodology used for the functional evaluation tests, the authors used female rats that undergo hormonal changes that alters neural regeneration …”
Section: Discussionmentioning
confidence: 99%
“…9 (3) The stimulating and measuring electrodes were on opposite sides of the surgical field, however, no standardized distance was established between them, which could produce abnormal CMAP 9 results or contamination of electrophysiological answers by branches of the sciatic, sural, tibia, or fibular nerves. 36 (4) The author evaluates CMAP amplitude but not duration or latency, which are also important when considering nerve function. Therefore, although the electrophysiological results obtained by Bittner et al 5 (2012) can be criticized, the behavioral tests demonstrate a significant improvement in neural regeneration in the long term (>60% regeneration in 12 weeks).…”
Section: Discussionmentioning
confidence: 99%
“…The author also reported that distal motor and sensory axon counts were higher in polyethylene glycoltreated rats. However, in addition to all the problems mentioned in the paragraph above about methodology used for the functional evaluation tests, 9,17,[34][35][36] the authors used female rats that undergo hormonal changes that alters neural regeneration. 42,43 Regarding histologic evaluation, there was no difference found in the total axonal count or in axonal density when comparing groups (Kruskal-Wallis test; P 5 .702; Figure 2; Table 2) as described by Bamba et al 41 Nonetheless, the mean axonal diameter of the groups that used the polyethylene glycol-fusion protocol (groups B and D) was increased (groups A and C; Bonferroni correction test; P .001; Figure 2; Table 2) showing that polyethylene glycol-fusion interfered with demyelination.…”
Section: Discussionmentioning
confidence: 99%
“…Salomone 40 (2013), using the same animal model with 1 surgical procedure only, describes a mortality rate of 8.3%. Regarding CMAPs, despite most authors claiming that the earlier the better, [34][35][36][37] the absence of statistical differences in the results of all the histologic and functional variables when we compare groups using only microsutures (group A vs group C; control groups), which is, up to today, the gold standard for neurotmesis, 34,37,39,44 in the third and sixth week after nerve severance (Mann-Whitney test; P .488 in both cases) leads us to the conclusion that regarding very severe nerve lesions, surgical intervention in feasible 24 or 72 hours after trauma with no consequences on the final outcome.…”
Peripheral nerve injury is common and negatively affects an individual's quality of life. Drugs used for peripheral nerve regeneration should aim to eliminate symptoms such as neuropathic pain and have therapeutic effects. In recent studies, pigment epithelium‐derived factor (PEDF) has been considered an essential therapeutic agent because of its potential neuroprotective properties. In this study, we aimed to investigate the efficacy of locally applied PEDF for peripheral nerve regeneration. Twenty‐four Wistar albino male rats were used. The study groups included Injury (n = 12) and Injury+PEDF (n = 12). An injury model was created by applying 50 N pressure to the right sciatic nerves in groups, and 10 μg/kg local PEDF was injected into the Injury+PEDF group. After 28 days of recovery, functional tests and stereological, immunohistochemical, and biochemical analyses were performed. A significant difference was found between the Injury and Injury+PEDF groups in amplitude, whereas no difference was found in latency. The number of myelinated axons and the myelinated axon area increased significantly in the Injury+PEDF group, while no statistically significant difference was found in myelin sheath thickness. Superoxide dismutase, catalase, and glutathione peroxidase activities were increased by PEDF, whereas they were suppressed in mesenchymal stem cells. PEDF exerts functional, quantitative, and antioxidative effects on sciatic nerve injury during neuroregeneration. In addition, when oxidative stress parameters were examined, it was seen that PEDF reduced oxidative stress following sciatic nerve injury.
The prognosis for postinjury peripheral nerve regeneration remains suboptimal. Although transplantation of exogenous Schwann cells (SCs) has been considered a promising treatment to promote nerve repair, this strategy has been hampered in practice by the limited availability of SC sources and an insufficient postengraftment cell retention rate. In this study, to address these challenges, SCs were aggregated into spheroids before being delivered to an injured rat sciatic nerve. We found that the three‐dimensional aggregation of SCs induced their acquisition of a repair phenotype, as indicated by enhanced levels of c‐Jun expression/activation and decreased expression of myelin sheath protein. Furthermore, our in vitro results demonstrated the superior potential of the SC spheroid‐derived secretome in promoting neurite outgrowth of dorsal root ganglion neurons, enhancing the proliferation and migration of endogenous SCs, and recruiting macrophages. Moreover, transplantation of SC spheroids into rats after sciatic nerve transection effectively increased the postinjury nerve structure restoration and motor functional recovery rates, demonstrating the therapeutic potential of SC spheroids. In summary, transplantation of preassembled SC spheroids may hold great potential for enhancing the cell delivery efficiency and the resultant therapeutic outcome, thereby improving SC‐based transplantation approaches for promoting peripheral nerve regeneration.
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