Contribution of pudendal nerve injury to stress urinary incontinence in a male rat model.

Urinary incontinence is a common complication following radical prostatectomy, as the surgery disturbs critical anatomical structures. This study explored how pudendal nerve (PN) injury affects urinary continence in male rats. In an acute study, leak point pressure (LPP) and external urethral sphincter electromyography (EMG) were performed on six male rats with an intact urethra, the urethra exposed (UE), the PN exposed (NE), and after PN transection (PNT). In a chronic study, LPP and EMG were tested in 67 rats 4 days, 3 weeks, or 6 weeks after sham PN injury, PN crush (PNC), or PNT. Urethras were assessed histologically. Acute PNT caused a significant decrease in LPP and EMG amplitude and firing rate compared to other groups. PNC resulted in a significant reduction in LPP and EMG firing rate 4 days, 3 weeks, and 6 weeks later. EMG amplitude was also significantly reduced 4 days and 6 weeks after PNC. Neuromuscular junctions were less organized and less innervated after PNC or PNT at all timepoints compared to sham injured animals. Collagen infiltration was significantly increased after PNC and PNT compared to sham at all timepoints. This rat model could facilitate preclinical testing of neuroregenerative therapies for post-prostatectomy incontinence.

[Diagnostics and surgical treatment of painful neuromas]. / Diagnostik und chirurgische Therapie schmerzhafter Neurome.

BACKGROUND: Painful neuromas that often develop after peripheral nerve injury require adequate diagnosis and treatment because of the suffering they cause. The scientific basis for the development of painful neuromas has not yet been sufficiently investigated. In addition to conservative procedures, a larger number of surgical techniques are available for treatment of painful neuromas. OBJECTIVE: A review of the basic principles, diagnostic and treatment options for painful neuromas. MATERIAL AND METHODS: Presentation of the scientific basis regarding the development of painful neuromas. Illustration and discussion of the most common diagnostic and treatment procedures. RESULTS: The scientific basis regarding the development of painful neuromas after peripheral nerve injury has not yet been adequately developed. In order to be able to make a correct diagnosis, the use of standardized diagnostic criteria and adequate imaging techniques are recommended. In the sense of a paradigm shift, the use of the formerly neuroma-bearing nerve for reinnervation of target organs is to be preferred over mere burying in adjacent tissue. CONCLUSION: In addition to standardized diagnostics the management of painful neuromas often requires a surgical intervention after all conservative therapeutic measures have been exhausted. As an alternative to restoring the continuity of the injured nerve, targeted reinnervation of electively denervated target organs by the formerly neuroma-bearing nerve is preferable over other techniques.

A porcine model of postoperative hemi-diaphragmatic paresis to evaluate a unilateral diaphragmatic pacemaker.

Unilateral phrenic nerve damage is a dreaded complication in congenital heart surgery. It has deleterious effects in neonates and children with uni-ventricular circulation. Diaphragmatic palsy, caused by phrenic nerve damage, impairs respiratory function, especially in new-borns, because their respiration depends on diaphragmatic contractions. Furthermore, Fontan patients with passive pulmonary perfusion are seriously affected by phrenic nerve injury, because diaphragmatic contraction augments pulmonary blood flow. Diaphragmatic plication is currently employed to ameliorate the negative effects of diaphragmatic palsy on pulmonary perfusion and respiratory mechanics. This procedure attenuates pulmonary compression by the abdominal contents. However, there is no contraction of the plicated diaphragm and consequently no contribution to the pulmonary blood flow. Hence, we developed a porcine model of unilateral diaphragmatic palsy in order to evaluate a diaphragmatic pacemaker. Our illustrated step-by-step description of the model generation enables others to replicate and use our model for future studies. Thereby, it might contribute to investigation and advancement of potential improvements for these patients.

Managing Complications Related to Peripheral Nerve Surgery: Selected Illustrative Cases.

Peripheral nerve surgery mostly involves elective procedures; thus, the associated complications are of great clinical, social, and medicolegal importance. Apart from the general perioperative morbidity, complications during interventions on peripheral nerves are extremely rare. However, iatrogenic peripheral nerve injuries during unrelated surgical procedures performed by those not specialised in peripheral nerve surgery remain the most significant group of complications, accounting for up to approximately 17% of all cases. The aims of this review are to provide better insight into the multifaceted nature of complications related to peripheral nerve surgery-from the perspective of their causes, treatment, and outcome-and to raise surgeons' awareness of the risks of such morbidity. It should be emphasized that intraoperative complications in peripheral nerve surgery are largely "surgeon-related" rather than "surgery-related"; therefore, they have great potential to be avoided.

Neuron-associated macrophage proliferation in the sensory ganglia is associated with peripheral nerve injury-induced neuropathic pain involving CX3CR1 signaling.

Resident macrophages are distributed across all tissues and are highly heterogeneous due to adaptation to different tissue-specific environments. The resident macrophages of the sensory ganglia (sensory neuron-associated macrophages, sNAMs) are in close contact with the cell body of primary sensory neurons and might play physiological and pathophysiological roles. After peripheral nerve injury, there is an increase in the population of macrophages in the sensory ganglia, which have been implicated in different conditions, including neuropathic pain development. However, it is still under debate whether macrophage accumulation in the sensory ganglia after peripheral nerve injury is due to the local proliferation of resident macrophages or a result of blood monocyte infiltration. Here, we confirmed that the number of macrophages increased in the sensory ganglia after the spared nerve injury (SNI) model in mice. Using different approaches, we found that the increase in the number of macrophages in the sensory ganglia after SNI is a consequence of the proliferation of resident CX3CR1+ macrophages, which participate in the development of neuropathic pain, but not due to infiltration of peripheral blood monocytes. These proliferating macrophages are the source of pro-inflammatory cytokines such as TNF and IL-1b. In addition, we found that CX3CR1 signaling is involved in the sNAMs proliferation and neuropathic pain development after peripheral nerve injury. In summary, these results indicated that peripheral nerve injury leads to sNAMs proliferation in the sensory ganglia in a CX3CR1-dependent manner accounting for neuropathic pain development. In conclusion, sNAMs proliferation could be modulated to change pathophysiological conditions such as chronic neuropathic pain.

FUS Contributes to Nerve Injury-Induced Nociceptive Hypersensitivity by Activating NF-κB Pathway in Primary Sensory Neurons.

Dysregulation of pain-associated genes in the dorsal root ganglion (DRG) is considered to be a molecular basis of neuropathic pain genesis. Fused in sarcoma (FUS), a DNA/RNA-binding protein, is a critical regulator of gene expression. However, whether it contributes to neuropathic pain is unknown. This study showed that peripheral nerve injury caused by the fourth lumbar (L4) spinal nerve ligation (SNL) or chronic constriction injury (CCI) of the sciatic nerve produced a marked increase in the expression of FUS protein in injured DRG neurons. Blocking this increase through microinjection of the adeno-associated virus (AAV) 5-expressing Fus shRNA into the ipsilateral L4 DRG mitigated the SNL-induced nociceptive hypersensitivities in both male and female mice. This microinjection also alleviated the SNL-induced increases in the levels of phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) and glial fibrillary acidic protein (GFAP) in the ipsilateral L4 dorsal horn. Furthermore, mimicking this increase through microinjection of AAV5 expressing full-length Fus mRNA into unilateral L3/4 DRGs produced the elevations in the levels of p-ERK1/2 and GFAP in the dorsal horn, enhanced responses to mechanical, heat and cold stimuli, and induced the spontaneous pain on the ipsilateral side of both male and female mice in the absence of SNL. Mechanistically, the increased FUS activated the NF-κB signaling pathway by promoting the translocation of p65 into the nucleus and phosphorylation of p65 in the nucleus from injured DRG neurons. Our results indicate that DRG FUS contributes to neuropathic pain likely through the activation of NF-κB in primary sensory neurons.SIGNIFICANCE STATEMENT In the present study, we reported that fused in sarcoma (FUS), a DNA/RNA-binding protein, is upregulated in injured dorsal root ganglion (DRG) following peripheral nerve injury. This upregulation is responsible for nerve injury-induced translocation of p65 into the nucleus and phosphorylation of p65 in the nucleus from injured DRG neurons. Because blocking this upregulation alleviates nerve injury-induced nociceptive hypersensitivity, DRG FUS participates in neuropathic pain likely through the activation of NF-κB in primary sensory neurons. FUS may be a potential target for neuropathic pain management.

Microglia senescence is related to neuropathic pain-associated comorbidities in the spared nerve injury model.

ABSTRACT: The increased presence of senescent cells in different neurological diseases suggests the contribution of senescence in the pathophysiology of neurodegenerative disorders. Microglia can adapt to any type of disturbance of the homeostasis of the central nervous system, and its altered activity can lead to permanent and unresolvable damage. The aim of this work was to characterize the behavioural phenotype of spared nerve injury mice and then associate it with senescence-related mechanisms. In this work, we investigated the timing of the onset of anxiety, depression, or memory decline associated with peripheral neuropathic pain and their correlation with the presence of microglial cellular senescence. Spared nerve injury mice showed a persistent pain hypersensitivity from 3 days after surgery. Twenty-eight days after nerve injury, they also developed anxiety, depression, and cognitive impairment. The appearance of these symptoms was coincident to a significant increase of senescence markers, such as ß-galactosidase and senescent-associated secretory phenotype, at the microglial level in the spinal cord and hippocampus of spared nerve injury animals. These markers were unaltered at previous time points. In murine immortalized microglial cells (BV2) stimulated with LPS 500 ng/mL for 10 days (4 hours/day) every other day, we observed an increase of ß-galactosidase and senescent-associated secretory phenotype appearance, a reduction of cell viability, and an increase of senescence-associated heterochromatin foci. Therefore, present findings could represent an important step to a better understanding of the pathophysiological cellular mechanisms in comorbidities related to neuropathic pain states.

Progesterone modulates the expression of spinal ephrin-B2 after peripheral nerve injury: New insights into progesterone mechanisms.

Recent studies have shown that the ephrin/Eph signaling pathway may contribute to the pathology of neuropathic pain. Drugs like progesterone may be used to counteract both thermal hyperalgesia and mechanical allodynia in different models of neuropathic pain. The present study was designed to determine progesterone's modulatory role on neuropathic pain and spinal expression of ephrin-B2 following chronic constriction nerve injury (CCI). Thirty-six adult male Wistar rats were used. The sciatic nerve was chronically constricted. Progesterone (5 mg/kg and 15 mg/kg) was administrated for 10 days (from day 1 up to day10) following sciatic constriction. Behavioral tests were performed before surgery (day 0) and on days 1, 3, 7, and 14 after CCI and before progesterone administration on the same days. Western blotting was performed on days 3, 7, and 14th post-surgery. The findings showed that after CCI, the expression of spinal cord ephrin-B2 increased significantly in parallel with mechanical allodynia and thermal hyperalgesia. Post-injury administration of progesterone (15 mg/kg but not 5) decreased mechanical allodynia, thermal hyperalgesia, and the expression of spinal ephrin-B2. It is concluded that post-injury repeated administration of progesterone could be an effective way of alleviating neuropathic pain by suppressing ephrin-B2 activation and helps to make the better design of steroid-based therapies to inhibit pain after peripheral injury.

Glucocorticoid Receptor/HCN4 Channels Interaction in Spinal Dorsal Horn Participates in the Regulation of Neuropathic Pain after Peripheral Nerve Injury in Rats.

We studied the interaction between glucocorticoid receptor (GR) and HCN4 channels in the rat model of spared nerve injury (SNI) in Sprague-Dawley rats (n=124). The animals were randomly divided into 6 groups: sham-operated (SO; n=24), SNI (reference group; n=20), and 4 experimental SNI groups intrathecally treated with dexamethasone (DEX; GR agonist; n=20), RU38486 (GR antagonist; n=20), ZD7288 (HCN channels blocker; n=20), and ZD7288+DEX (n=20). The paw mechanical withdrawal threshold (PWT) was measured one day before surgery (SO group) and on days 1, 3, 7, 14, and 21 after surgery. Behavioral results showed that mechanical hyperalgesia appeared on day 1 after SNI, while PWT decreased gradually with time. The expression of GR and HCN4 channels in L4-L6 dorsal horn of the spinal cord was detected by Western blotting and immunohistochemistry. In the reference group, SNI significantly increased GR expression up to day 14 after surgery in comparison with the SO group. The expression of GR showed a tendency to increase in the DEX group (with the maximum expression on days 14 and 21), significantly increased in the RU38486 group (maximum on day 7). In the ZD7288 group, GR expression was lower than in the SNI group and did not change throughout the experiment, suggesting that ZD7288 could block the expression of GR. In the DEX group, the expression of HCN4 channels was significantly higher on day 1 after SNI, but there were no differences in this parameter between the RU38486 and ZD7288 groups. In the ZD7288+DEX group, the expression of HCN4 channels significantly increased on days 14 and 21 after SNI. Thus, GR and HCN4 have the same linkage in the formation of central sensitization after SNI, but antagonists have no significant effect on the improvement of pain behavior.

Activation of Double-Stranded RNA-Activated Protein Kinase in the Dorsal Root Ganglia and Spinal Dorsal Horn Regulates Neuropathic Pain Following Peripheral Nerve Injury in Rats.

Double-stranded RNA (dsRNA)-activated kinase (PKR) is an important component in inflammation and immune dysfunction. However, the role of PKR in neuropathic pain remains unclear. Here, we showed that lumbar 5 spinal nerve ligation (SNL) led to a significant increase in the level of phosphorylated PKR (p-PKR) in both the dorsal root ganglia (DRG) and spinal dorsal horn. Images of double immunofluorescence staining revealed that p-PKR was expressed in myelinated A-fibers, unmyelinated C-fibers, and satellite glial cells in the DRG. In the dorsal horn, p-PKR was located in neuronal cells, astrocytes, and microglia. Data from behavioral tests showed that intrathecal (i.t.) injection of 2-aminopurine (2-AP), a specific inhibitor of PKR activation, and PKR siRNA prevented the reductions in PWT and PWL following SNL. Established neuropathic pain was also attenuated by i.t. injection of 2-AP and PKR siRNA, which started on day 7 after SNL. Prior repeated i.t. injections of PKR siRNA prevented the SNL-induced degradation of IκBα and IκBß in the cytosol and the nuclear translocation of nuclear factor κB (NF-κB) p65 in both the DRG and dorsal horn. Moreover, the SNL-induced increase in interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) production was diminished by this treatment. Collectively, these results suggest that peripheral nerve injury-induced PKR activation via NF-κB signaling-regulated expression of proinflammatory cytokines in the DRG and dorsal horn contributes to the pathogenesis of neuropathic pain. Our findings suggest that pharmacologically targeting PKR might be an effective therapeutic strategy for the treatment of neuropathic pain.

Inclusion of open injuries in an updated Schenck classification of knee dislocations based on a global Delphi consensus study.

OBJECTIVES: Knee dislocations (KDs) are complex injuries defined as incongruity of the tibiofemoral joint, which leads to tears of two or more of the main stabilising knee ligaments, and they are often associated with damage to surrounding soft tissue or neurovascular structures. A classification system for these injuries should be simple and reproducible and allow communication among surgeons for surgical planning and outcome prediction. The aim of this study was to formulate a list of factors, prioritised by high-volume knee surgeons, that should be included in a KD classification system. METHODS: A global panel of orthopaedic knee surgery specialists participated in a Delphi process. The first survey employed 91 orthopaedic surgeons to generate a list of patient- and system-specific factors that should be included in a KD classification system that may affect surgical planning and outcomes. This list was subsequently prioritised by 27 identified experts (mean 15.3 years of experience) from Brazil (n = 9), USA (n = 6), South Africa (n = 4), India (n = 4), China (n = 2), and the United Kingdom (n = 2). The items were analysed to find factors that had at least 70% consensus for inclusion in a classification system. RESULTS: Of the 12 factors identified, four (33%) achieved at least 70% consensus for inclusion in a classification system. The factors deemed critical for inclusion in a classification system included vascular injuries (89%), common peroneal nerve injuries (78%), number of torn ligaments (78%), and open injuries (70%). CONCLUSION: Consensus for inclusion of various factors in a KD classification system was not easily achieved. The wide geographic distribution of participants provides diverse insight and makes the results of the study globally applicable. The most important factors to include in a classification system as determined by the Delphi technique were vascular injuries, common peroneal nerve injuries, number of torn ligaments, and open injuries. To date, the Schenck anatomic classification system most accurately identifies these patient variables with the addition of open injury classification. The authors propose to update the Schenck classification system with the inclusion of open injuries as an additional modifier, although this is only a small step in updating the classification, and further studies should evaluate the inclusion of more advanced imaging modalities. Future research should focus on integrating these factors into useful existing classification systems that are predictive of surgical treatment and patient outcomes.

Acetyl-L-carnitine improves erectile function in bilateral cavernous nerve injury rats via promoting cavernous nerve regeneration.

BACKGROUND: Neurogenic erectile dysfunction (NED) caused by cavernous nerve (CN) injury is a typical complication after pelvic surgery, which lacks efficient treatments. Acetyl-L-carnitine (ALCAR) has been proven to promote nerve repair. OBJECTIVES: To investigate the effect and potential mechanism of ALCAR in the treatment of NED. MATERIALS AND METHODS: Thirty-two rats were randomly divided into bilateral CN injury (BCNI) group, BCNI + lower-dose ALCAR (50 mg/kg/day) group, BCNI + higher-dose (100 mg/kg/day) group, and sham-operated group. Erectile function was assessed 14 days after daily intraperitoneal injection of ALCAR or placebo. The penile tissues were gathered for subsequent histological and molecular biological analysis. Rat Schwann cell (SC) line S16 was used to verify the mechanism of ALCAR in vitro. RESULTS: We found that the erectile function of the rats in the BCNI group was severely impaired, which was improved considerably in both BCNI+ALCAR-LD and BCNI+ALCAR-HD groups. Also, we observed decreased smooth muscle and increased collagen content in the corpus cavernosum in the BCNI group. The expressions of fibrosis markers transforming growth factor-beta (TGF-ß), connective tissue growth factor (CTGF), and Smad 2/3 were significantly up-regulated in the BCNI group. The above changes were alleviated after the administration of lower and higher-dose ALCAR. Meanwhile, the nitric oxide (NO)/cyclic guanosine monophosphate pathway (cGMP) was promoted and the Ras homolog gene family member A (RhoA)/Rho-associated protein kinase (ROCK) pathway was inhibited in the corpus cavernosum of BCNI rats after ALCAR treatment, accompanied by increased neuronal nitric oxide synthase (nNOS) and down-regulated tyrosine hydroxylase (TH). In vitro, ALCAR promoted the migration and proliferation of SC and increased the expression of 22-kD peripheral myelin protein and nerve growth factor (NGF). Further, rats treated with ALCAR had high expression of ATF3 and S100 in the distal nerve tissues of the CN extrusion site. DISCUSSION AND CONCLUSION: ALCAR could promote nerve repair and regeneration, inhibit penile fibrosis, and improve penile erection by promoting the proliferation and migration of SC and the secretion of NGF. Our study confirms that ALCAR may be a potential treatment strategy for NED.

Targeting Vascular endothelial growth factor A with soluble vascular endothelial growth factor receptor 1 ameliorates nerve injury-induced neuropathic pain.

Neuropathic pain is a distressing medical condition with few effective treatments. The role of Vascular endothelial growth factor A (VEGFA) in inflammation pain has been confirmed in many researches. However, the mechanism of VEGFA affects neuropathic pain remains unclear. In this study, we demonstrated that VEGFA plays an important role in spare nerve injury (SNI)-induced neuropathic pain, which is mediated by enhanced expression and colocalized of VEGFA, p-AKT and TRPV1 in SNI-induced neuropathic pain model. Soluble VEGFR1 (sFlt1) not only relieved mechanical hyperalgesia and the expression of inflammatory markers, but ameliorated the expression of VEGFA, VEGFR2, p-AKT, and TRPV1 in spinal cord. However, these effects of sFlt1 can be blocked by rpVEGFA and by 740 Y-P. Therefore, our study indication that targeting VEGFA with sFlt1 reduces neuropathic pain development via the AKT/TRPV1 pathway in SNI-induced nerve injury. This study elucidates a new therapeutic target for neuropathic pain.

Antiallodynic action of phosphodiesterase inhibitors in a mouse model of peripheral nerve injury.

Neuropathic pain arises as a consequence of a lesion or disease affecting the somatosensory nervous system. It is accompanied by neuronal and non-neuronal alterations, including alterations in intracellular second messenger pathways. Cellular levels of 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic guanosine monophosphate (cGMP) are regulated by phosphodiesterase (PDE) enzymes. Here, we studied the impact of PDE inhibitors (PDEi) in a mouse model of peripheral nerve injury induced by placing a cuff around the main branch of the sciatic nerve. Mechanical hypersensitivity, evaluated using von Frey filaments, was relieved by sustained treatment with the non-selective PDEi theophylline and ibudilast (AV-411), with PDE4i rolipram, etazolate and YM-976, and with PDE5i sildenafil, zaprinast and MY-5445, but not by treatments with PDE1i vinpocetine, PDE2i EHNA or PDE3i milrinone. Using pharmacological and knock-out approaches, we show a preferential implication of delta opioid receptors in the action of the PDE4i rolipram and of both mu and delta opioid receptors in the action of the PDE5i sildenafil. Calcium imaging highlighted a preferential action of rolipram on dorsal root ganglia non-neuronal cells, through PDE4B and PDE4D inhibition. Rolipram had anti-neuroimmune action, as shown by its impact on levels of the pro-inflammatory cytokine tumor necrosis factor-α (TNFα) in the dorsal root ganglia of mice with peripheral nerve injury, as well as in human peripheral blood mononuclear cells (PBMCs) stimulated with lipopolysaccharides. This study suggests that PDEs, especially PDE4 and 5, may be targets of interest in the treatment of neuropathic pain.

Intrathecal IGF2 siRNA injection provides long-lasting anti-allodynic effect in a spared nerve injury rat model of neuropathic pain.

Previous studies have shown an increase of insulin-like growth factor-2 (IGF2) in animal models of neuropathic pain. We aimed to examine the hypothesis that reducing the expression of IGF2 using intrathecal IGF2 small-interfering RNA (siRNA) would attenuate the development of neuropathic pain in rats after spared nerve injury (SNI). Male Wistar rats were divided into three groups: sham-operated group, in which surgery was performed to cut the muscles without injuring the nerves; SNI group, in which SNI surgery was performed to sever the nerves; and SNI + siRNA IGF2 group, in which SNI surgery was performed, and IGF2-siRNA was administered intrathecally 1 day after SNI. The rats were assessed for mechanical allodynia and cold allodynia 1 day before surgery (baseline), and at 2, 4, 6, 8, and 10 days after siRNA treatment. The rat spinal cord was collected for quantitative polymerase chain reaction and western blot analysis. Compared with the SNI group, rats that received IGF2 siRNA showed a significantly increased SNI-induced paw-withdrawal threshold to metal filament stimulation from Day 4 to Day 10 after SNI surgery. IGF2 siRNA significantly decreased the response duration from the acetone test from Day 2 to Day 10 following SNI surgery. SNI increased IGF2 mRNA expression on Day 2 and increased IGF2 protein expression on Day 8 and Day 10 in the spinal cord of the SNI rats. However, the above-mentioned effects of IGF2 mRNA and protein expression were significantly inhibited in the SNI + IGF2 siRNA group. We demonstrated that intrathecal administration of IGF2 siRNA provided significant inhibition of SNI-induced neuropathic pain via inhibition of IGF2 expression in the spinal cord. The analgesic effect lasted for 10 days. Further exploration of intrathecal IGF2 siRNA administration as a potential therapeutic strategy for neuropathic pain is warranted.

Cavernous Nerve Injury Resulted Erectile Dysfunction and Regeneration.

Erectile dysfunction (ED) is an important cause of reduced quality of life for men and their partners. Recent studies have found that cavernous nerve injury (CNI) during prostate cancer surgery and other pelvic surgery results in medically induced CNIED in more than 80% of patients. The efficacy of first- and second-line treatment options for ED is poor. A great deal of research has been devoted to exploring new methods of neuroprotection and nerve regeneration to save erectile function in patients with CNIED, especially in patients with cavernous nerve injury after prostate cancer surgery. In addition, such as neuromodulatory proteins, proimmune ligands, gene therapy, stem cell therapy, and the current cutting-edge low-energy shock wave therapy have shown advantages in basic research and limited clinical studies. In the context of today's modern medicine, these new therapeutic techniques are expected to be new tools in the treatment of cavernous nerve injury erectile dysfunction. This article presents the main causes, mechanisms, and treatment of cavernous nerve injury erectile dysfunction and combines them with new treatment strategies.

Macrophage Activation in the Dorsal Root Ganglion in Rats Developing Autotomy after Peripheral Nerve Injury.

Autotomy, self-mutilation of a denervated limb, is common in animals after peripheral nerve injury (PNI) and is a reliable proxy for neuropathic pain in humans. Understanding the occurrence and treatment of autotomy remains challenging. The objective of this study was to investigate the occurrence of autotomy in nude and Wistar rats and evaluate the differences in macrophage activation and fiber sensitization contributing to the understanding of autotomy behavior. Autotomy in nude and Wistar rats was observed and evaluated 6 and 12 weeks after sciatic nerve repair surgery. The numbers of macrophages and the types of neurons in the dorsal root ganglion (DRG) between the two groups were compared by immunofluorescence studies. Immunostaining of T cells in the DRG was also assessed. Nude rats engaged in autotomy with less frequency than Wistar rats. Autotomy symptoms were also relatively less severe in nude rats. Immunofluorescence studies revealed increased macrophage accumulation and activation in the DRG of Wistar rats. The percentage of NF200+ neurons was higher at 6 and 12 weeks in Wistar rats compared to nude rats, but the percentage of CGRP+ neurons did not differ between two groups. Additionally, macrophages were concentrated around NF200-labeled A fibers. At 6 and 12 weeks following PNI, CD4+ T cells were not found in the DRG of the two groups. The accumulation and activation of macrophages in the DRG may account for the increased frequency and severity of autotomy in Wistar rats. Our results also suggest that A fiber neurons in the DRG play an important role in autotomy.

Combination Therapy with a JNK Inhibitor and Hepatocyte Growth Factor for Restoration of Erectile Function in a Rat Model of Cavernosal Nerve Injury: Comparison with a JNK Inhibitor Alone or Hepatocyte Growth Factor Alone.

We determined if combined administration of JNK-inhibitors and HGF (hepatocyte-growth-factor) would restore erectile-function through both antiapoptotic and regenerative effects in a rat model of cavernous-nerve-crush-injury (CNCI), and compared the results with administration of JNK-inhibitor alone or HGF alone. We randomized 70 rats into 5 groups: sham-surgery-group (S), CNCI (I) group, a group treated with once-daily intraperitoneal-administration of 10.0-mg/kg of JNK-inhibitors (J), a twice-weekly intracavernosal-administration of 4.2-µg HGF group (H), and a combined-treatment with 10.0-mg/kg JNK-inhibitors and 4.2-µg HGF group (J+H). We investigated erectile-responses to electrostimulation, histological-staining, caspase-3-activity-assay, and immunoblotting at two-weeks postoperatively. The three treatment groups showed improvements in erectile-responses (ICP/MAP and AUC/MAP ratios) compared to Group-I. The erectile-responses in Group-J+H were greater than those in Group-J or Group-H. The erectile-responses in Group-J+H were generally normalized. Caspase-3-activity and cJun-phosphorylation in Group-J and Group-J+H improved compared to Group-I, whereas caspase-3-activity in Group-H partially improved. Protein-expression of PECAM-1, eNOS-phosphorylation, and smooth-muscle content in Group-J+H were normalized, although those in Group-J or Group-H were partially restored. Combination therapy with JNK-inhibitors and HGF can generally normalize erectile-function through anti-apoptosis and preservation of endothelium or SM in rat CNCI model. The combined treatment appears to be superior to the respective agent alone in terms of therapeutic effects.

The Efficacy of Schwann-Like Differentiated Muscle-Derived Stem Cells in Treating Rodent Upper Extremity Peripheral Nerve Injury.

BACKGROUND: There is a pressing need to identify alternative mesenchymal stem cell sources for Schwann cell cellular replacement therapy, to improve peripheral nerve regeneration. This study assessed the efficacy of Schwann cell-like cells (induced muscle-derived stem cells) differentiated from muscle-derived stem cells (MDSCs) in augmenting nerve regeneration and improving muscle function after nerve trauma. METHODS: The Schwann cell-like nature of induced MDSCs was characterized in vitro using immunofluorescence, flow cytometry, microarray, and reverse-transcription polymerase chain reaction. In vivo, four groups (n = 5 per group) of rats with median nerve injuries were examined: group 1 animals were treated with intraneural phosphate-buffered saline after cold and crush axonotmesis (negative control); group 2 animals were no-injury controls; group 3 animals were treated with intraneural green fluorescent protein-positive MDSCs; and group 4 animals were treated with green fluorescent protein-positive induced MDSCs. All animals underwent weekly upper extremity functional testing. Rats were euthanized 5 weeks after treatment. The median nerve and extrinsic finger flexors were harvested for nerve histomorphometry, myelination, muscle weight, and atrophy analyses. RESULTS: In vitro, induced MDSCs recapitulated native Schwann cell gene expression patterns and up-regulated pathways involved in neuronal growth/signaling. In vivo, green fluorescent protein-positive induced MDSCs remained stably transformed 5 weeks after injection. Induced MDSC therapy decreased muscle atrophy after median nerve injury (p = 0.0143). Induced MDSC- and MDSC-treated animals demonstrated greater functional muscle recovery when compared to untreated controls (hand grip after induced MDSC treatment: group 1, 0.91 N; group 4, 3.38 N); p < 0.0001) at 5 weeks after treatment. This may demonstrate the potential beneficial effects of MDSC therapy, regardless of differentiation stage. CONCLUSION: Both MDSCs and induced MDSCs decrease denervation muscle atrophy and improve subsequent functional outcomes after upper extremity nerve trauma in rodents.

Effects of Cells Self-aggregation in the Treatment of Neurogenic Erectile Dysfunction With Traditional Single Cell Suspension of Adipose-derived Stem Cells.

OBJECTIVE: To clarify the effects of cellular self-aggregation of adipose-derived stem cells (ADSCs) on erectile function (EF). METHODS: A model of neurogenic erectile dysfunction was performed using bilateral cavernous nerve crush injury in rats. ADSCs suspensions (1 × 106/0.2 ml), were administered via intracavernous injection (ICI) after being allowed to shelve for 0 minute (ICI 0) or 60 minutes (ICI 60) in vitro, as well as cell aggregates isolated from ICI 60 (ICI A). The caudal vein injection group (CVI 60) was used to evaluate whether cell self-aggregation was beneficial to EF when introduced into the peripheral circulation. One day after the transplantation, the distribution of cells was observed. EF and histopathological changes were evaluated after 4 weeks. RESULTS: Approximately 85% of ADSCs self-aggregated into cell clusters at 60 minutes. The ICI 60 had more significant improvements in EF and more visualized ADSCs retained in the corpus cavernosum (CC) than ICI 0 and CVI 60 (P <.05), but no significant difference between ICI 60 and ICI A. In the CVI 60 group, the cell clusters formed by self-aggregation could hardly reach the CC and were mostly found in lung tissue. Immunofluorescence staining showed increased the content of expressing biomarkers of smooth muscle, nerve within the CC tissue in the ICI groups when compared to the CVI group. CONCLUSION: ADSCs self-aggregation before ICI may be an influential factor in the treatment of neurogenic erectile dysfunction. Its potential mechanism may be through improving cell retention in the CC.