NGF Expression Research Articles

Neuroprotective effects of MK-801 against traumatic brain injury in immature rats

Traumatic brain injury (TBI) is a major health problem in pediatric ages and also has major social, economic, and emotional outcomes, with diverse sequelae in many spheres of everyday life. We aimed to investigate the effect of MK-801, a competitive NMDA receptor antagonist, on hippocampal damage and behavioral deficits on 10-day-old rat pups subjected to contusion injury. The aims of the present study were to determine: (i) the short term effects of MK-801 on hippocampal BDNF, NGF and NMDA receptor immunoreactivity and neuron density in hippocampus (ii) long term effects of MK-801 on cognitive dysfunction following TBI in the immature rats. MK-801, was injected intraperitoneally at the doses of 1mg/kg of body weight immediately after induction of traumatic injury. Hippocampal damage was examined by cresyl violet staining, BDNF, NGF and NMDAR receptor immunohistochemistry on P10 day and behavioral alterations were evaluated using elevated plus maze and novel object recognition tests two months after the trauma. Histopathological and immunohistochemical evaluations showed that treatment with a single dose of 1mg/kg MK-801 (i.p.) significantly ameliorated the trauma induced hippocampal neuron loss and decreased BDNF, NGF and NMDAR expressions in CA1, CA3 and DG hippocampal brain regions. Additionally, treatment with MK-801 ameliorated anxiety and hippocampus dependent memory of animals subjected to trauma. These results show that acute treatment of MK-801 has a neuroprotective role against trauma induced hippocampal neuron loss and associated cognitive impairment in immature rats.

Role of mast cells in estrogen-mediated experimental endometriosis in rats

To investigate the role of mast cells in the pathogenesis of estrogen-mediated experimental endometriosis in rats. Endometriosis model was established by transplanting autologous fragments of uterus to the inner surface of the abdominal wall in 24 un-pregnant female Sprague Dawley rats. The rats were divided randomly into three groups (n=8 in each group), and were injected with different doses of estrogen: high-dose group (200 μg·kg⁻¹·d⁻¹), low-dose group (100 μg·kg⁻¹·d⁻¹) and the control group (0 μg·kg⁻¹·d⁻¹). The ovaries were surgically removed in high-dose and low-dose groups. Four rats were sacrificed in each group at 2 and 4 weeks after surgery. Their serum estradiol levels, size of lesions, total number of mast cells and degranulations, serum TNF-α levels, expression of tryptase and NGF in tissues were analyzed and compared among groups. The mean levels of serum estradiol 2 weeks and 4 weeks after model established and serum TNF-α at 4 weeks in estrogen-treated groups were significantly higher than those in control group (all P<0.05). The mean size of endometriotic lesions in the estrogen-treated groups was also significantly larger than that in the control group 2 weeks and 4 weeks after model established (all P<0.05). Meanwhile, both at week 2 and week 4, the mean ratio of degranulation/total number of mast cells by toluidine blue staining in low-dose estrogen group was significantly higher than that in the control group (P<0.05). The expression of NGF in high-dose estrogen group was significantly higher than that in the control group at week 4(P<0.05). Estrogen can promote the growth of endometriotic lesions and may mediate the pathogenesis of endometriosis by activating mast cells, which may be associated with increasing TNF-α and NGF levels.

Mechanical Injury to Human Intervertebral Discs and Isolated Cells Initiates Events Implicated in Degeneration and Pain

Introduction Painful degenerating intact human intervertebral discs (IVDs) produce elevated levels of Toll-like receptors (TLRs), cytokines, and neuropeptides but events regulating their expression are poorly understood. Mechanical overload has been proposed as one potential initiating mechanism. The aim of this study was to investigate the cellular responses in IVDs and isolated disc cells exposed to mechanical overload or strain. Methods Lumbar spine segments were harvested from consenting donors via the Transplant Quebec organ donation program in Montreal, Quebec, Canada. A total of nine discs from six donors were used in this study. Intact IVDs were prepared and cells isolated using a standard technique. Intact discs with cartilaginous endplates were loaded with a single ramp compression peaking at either approximately 0.2 MPa (noninjurious) or about 1.5 MPa (injurious) stress applied at a rate of 30% strain per second. Injurious compression protocol consistently yields endplate fracture. Discs were immediately put in low serum containing media after loading. For isolated cell experiments, 2 × 105 nucleus pulposus (NP) and annulus fibrosus (AF) cells were seeded on flexible or static silicone dishes. The flexible dishes were exposed to a 20% magnitude cyclic mechanical strain at 0.0001 Hz was applied to the cultures for 8 h/d over 2 days. Conditioned media was collected and RNA was isolated. Quantitative RT-PCR was performed to assess TLR, NGF, and TNF gene expression. Conditioned media from intact discs and isolated cells was applied to PC12 cells and neurite outgrowth was assessed. Commercially available cytokine arrays were used to investigate protein levels of cytokines released from intact discs and isolated cells. Results Elevated levels of proteoglycan, inflammatory cytokines, and pain mediators were released from intact discs exposed to injurious loading. The highest levels were found 3 days postinjury and the conditioned media caused significantly induced neurite outgrowth in PC12 cells compared with that of the control group. About 50% of the cells in the IVDs died as a result of the inflicted trauma. Isolated NP and AF cells were exposed to a high-magnitude strain at low frequency to preserve cell attachments and maintain cell viability. The protocol was applied to evaluate if the adverse mechanical stimulation of the cells or the induced cell death caused by the injurious loading of the intact IVDs was responsible for the increased expression of inflammatory cytokines and pain mediators. Our data showed that high-magnitude low-frequency strain is sufficient to induce expression inflammatory cytokines and pain mediators in the absence of cell death. We also found a small but significant upregulation of TLR 2 and 4 in both NP and AF cells. Conclusion Cell death and cytokine production combined with loss of glycosaminoglycan indicate that mechanical injury to intact IVDs and isolated cells initiates cellular processes leading to disc degeneration. Once the proteoglycan content in the matrix has been degraded, elevated levels of NGF could lead to neuronal ingrowth directly causing pain. Increased TLR expression induced by high strain may prime cells toward a degenerate phenotype and could be a novel therapeutic target for degenerative disc disease.

TGF-β is a potent inducer of nerve growth factor in articular cartilage via the ALK5-Smad2/3 pathway. potential role in OA related pain?

Purpose: Pain is the main problem for patients with OA. Unfortunately, pain relief is not effective in every individual. In general, pain is linked to inflammation. However, in a subset of OA patients pain is experienced without obvious inflammation driving the pain. This indicates there must be an additional alternative source of pain besides inflammation. NGF inhibition has been shown very efficient in blocking pain during OA, but the exact source of NGF is unclear. NGF is elevated in human OA,as well as in animal models of OA with cartilage damage without inflammation.TGF-beta is released from cartilage upon damage. We investigated whether TGF-beta could contribute to NGF expression in the joint. Furthermore, we studied the specific Smad-related TGF-beta pathways involved in this process. Methods: Murine and human chondrocyte cell lines, primary bovine and human chondrocytes, and cartilage explants from bovine metacarpal joints and human OA joints were stimulated with TGF-β1 and/or IL-1β as a positive control for NGF induction. We analyzed NGF expression on mRNA level with QPCR and stained human OA cartilage for NGF immunohistochemically. Cultures were additionally pre-incubated with inhibitors for TAK1 (oxozeaenol), Smad2/3 (SB-505124) or Smad1/5/8 (LDN-193189) signaling to identify the TGF-β pathway inducing NGF. Results: We found that TGF-beta was capable of inducing NGF expression, even in low dosage of 1 ng/ml. NGF expression was consistently induced at higher levels by TGF-β than IL-1 in all of our experiments: murine, bovine and human origin, in cell lines, primary chondrocytes and explants cultures. Combining TGF-beta with IL-1 did not result in higher levels of NGF expression than those already reached by a single dose of TGF-beta alone. As TAK1 is a common pathway component of both IL-1 and TGF-beta signaling, we initially expected TAK1 to be dominant and pivotal in NGF induction. TAK1 inhibition consistently reduced (but not blocked) TGF-β-induced NGF whereas it fully blocked IL-1β-induced NGF expression. In contrast, ALK5-Smad2/3 inhibition fully blocked TGF-β-induced NGF expression. Blocking the Smad1/5/8 pathway with LDN did not have an effect on TGF-beta-induced NGF. In human OA primary chondrocytes we found that there was a large variation in basal NGF levels (mRNA and histology). Upon stimulation with TGF-β we found a consistent higher level of NGF induction than upon stimulation with IL-1, which was not related to the basal levels of NGF. In explants of human OA cartilage we observed chondrocytes positive staining for NGF. When stimulating human OA cartilage with TGF-beta NGF expression increased, which could be fully blocked by inhibiting ALK5-Smad2/3 signaling. Conclusions: This is the first time that it is shown that TGF-β induces NGF expression in (primary) chondrocytes. Moreover, we found that TGF-beta consistently induced NGF at higher levels than IL-1. In addition, IL-1 induced NGF could be fully abrogated by TAK1 inhibition, but this only had a reducing effect on TGF-beta induced NGF expression. In contrast blocking signaling via ALK5-Smad2/3 fully abrogated the TGF-beta-induced NGF expression. Clearly, our data show that there are sources of NGF other than inflammation in the joint and that this should be taken into account when studying pain in OA.

Effect of Draconis Sanguis-containing serum on NGF, BDNF, CNTF, LNGFR, TrkA, GDNF, GAP-43 and NF-H expressions in Schwann cells

To observe the effect of Draconis Sanguis-containing serum on the expressions of NGF, BDNF, CNTF, LNG-FR, TrkA, GDNF, GAP-43 and NF-H in Schwann cells, and investigate the possible mechanism of Draconis Sanguis to promote peripheral nerve regeneration. SD rats were randomly divided into 2 groups: the Draconis Sanguis group (orally administered with Draconis Sanguis-containing balm solution) and the blank group (equivoluminal balm) to prepare Draconis Sanguis-containing serum and blank control serum. Schwann cells were extracted from double sciatic nerves of three-day-old SD rats, divided into 2 groups: the Draconis Sanguis group and the blank control group, and respectively cultured with 10% Draconis Sanguis-containing serum or blank control serum. The mRNA expressions of NGF, BDNF, CNTF and other genes in Schwann cells were measured by RT-PCR analysis 48 hours later. Most of the Schwann cells were bipolar spindle and arranged shoulder to shoulder or end to end under the microscope and identified to be positive with the immunocytochemical method. To compare with the blank group, mRNA expressions of NGF, LNGFR, GDNF and GAP-43 significantly increased (P < 0.01). Whereas that of BDNF decreased significantly (P < 0.05), and so did that of TrkA, CNTF (P < 0.01), with no remarkable difference in NF-H-mRNA. Traditional Chinese medicine Draconis Sanguis may show effect in nerve regeneration by up-regulating mRNA expressions of NGF, LNGFR, GDNF and GAP-43 and down-regulating mRNA expressions of TrkA, BDNF and CNTF.

Selective Endothelin-B Receptor Stimulation Increases Vascular Endothelial Growth Factor in the Rat Brain during Postnatal Development.

Endothelin, vascular endothelial growth factor and nerve growth factor play important roles in development of the central nervous system. ET(B) receptors have been shown to promote neurovascular remodeling in the adult ischemic brain through an increase in VEGF and NGF. It is possible that ET(B) receptors may be involved in postnatal development of the brain through VEGF and NGF. In the present study, the brains of male rat pups on postnatal days 1, 7, 14 and 28 were analyzed for expression of ET(B) receptors, VEGF and NGF. In order to determine the effect of ET(B) receptor stimulation, a separate group of pups were administered saline or ET(B) receptor agonist, IRL-1620, on day 21, and their brains were analyzed on day 28. The intensity of ET(B) receptor and VEGF staining in the vasculature as well as the number of blood vessels of normal pups increased with age and was significantly higher on postnatal day 14 compared to day 1 and day 7. In contrast, both ET(B) and NGF staining intensity in the cortex and subventricular zones decreased (P<0.01) at postnatal day 14 compared to earlier time points. Stimulation of ET(B) receptors resulted in a significant increase in VEGF and ET(B) intensity both in the vasculature and the brain (P<0.05), however, IRL-1620 did not produce any change in NGF expression. Results indicate that ET(B) receptors appear to play a role in the development of the CNS and selective stimulation of ET(B) receptors enhances VEGF but not NGF in the postnatal rat brain.

Th2 cytokines enhance TrkA expression, upregulate proliferation, and downregulate differentiation of keratinocytes

BackgroundNerve growth factor (NGF), a neurotrophin that plays a critical role in developmental neurobiology, is released by proliferating keratinocytes and induces proliferation. ObjectiveThe aim of this study was to investigate the role of tyrosine kinase receptor A (TrkA), a high-affinity receptor of NGF, in human keratinocytes. MethodsExpression of TrkA and NGF in skin diseases was investigated by immunohistochemistry. Expression of TrkA in cells was examined by Western blotting and RT-PCR. Cell proliferation was assessed by BrdU assay. ResultsWe first determined the expression of TrkA and NGF in skin samples from patients with atopic dermatitis, prurigo nodularis, psoriasis vulgaris, and seborrheic keratosis. TrkA was only expressed in proliferating basal cells, and its expression was enhanced in atopic dermatitis samples. NGF expression was enhanced in atopic dermatitis and prurigo nodularis samples and in some samples from seborrheic keratosis patients. Investigation of the role of TrkA in vitro using normal human epidermal keratinocytes (NHEK) revealed that TrkA was significantly enhanced by the T helper type 2 (Th2) cytokines interleukin (IL)-4 and IL-13 but not by other inflammatory cytokines, such as IL-1β, tumor necrosis factor α, interferon γ, or epidermal growth factor. On the other hand, expression of NGF was not altered by Th2 cytokines. Notably, inhibition of TrkA significantly reversed the effects of IL-4 on proliferation and differentiation. Furthermore, overexpression of TrkA enhanced proliferation of NHEK. These results indicate that IL-4-induced TrkA expression in keratinocytes modulates proliferation and differentiation of these cells. ConclusionIncreased TrkA expression in keratinocytes in atopic dermatitis may contribute to the observed epidermal hyperproliferation in these patients.

Reversal of experimental severe pulmonary hypertension by NGF inhibition

Introduction NGF expression is significantly increased in a new rat model of severe pulmonary hypertension (SPH) combining injection of monocrotaline (MCT) and chronic hypoxia (CH). Administration of anti-NGF blocking antibodies in vivo in this SPH model prevented, at least partially, increase in pulmonary arterial pressure (PAP), pulmonary arterial inflammation, remodelling, and hyperreactivity. In the present work, we studied whether anti-NGF blocking antibodies also displayed curative effects in this SPH model. Methods SPH was induced in rats by a single injection of MCT [day (D)1, 60 mg/kg] followed by chronic hypoxia (CH, 0.5 atm, D3 to D28). Anti-NGF blocking antibodies (10 μg/kg IP) were administered curatively at D15-19-22-26. Mean pulmonary arterial pressure (mPAP) and Fulton index (index of cardiac remodelling) were assessed at D28. Secretion of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) from rat pulmonary arteries were evaluated by Elisa. Pulmonary arterial reactivity to phenylephrine (PHE) or prostaglandin F2α (PGF2α) was evaluated ex vivo. Pulmonary arterial remodelling was assessed by measuring medial thickness and luminal occlusion (eosin-hematoxylin or van Gieson stainings). Results In the SPH model, mPAP and Fulton index were significantly increased compared to controls. Increased secretions of IL-1β and TNF-α were observed, as well as pulmonary arterial remodelling and hyperreactivity to both PHE and PGF2α. The curative treatment with anti-NGF blocking antibodies totally reversed TNF-α increased secretion, pulmonary arterial medial thickness, luminal occlusion and hyperreactivity to PHE. This curative protocol also partially reduced increased mPAP, IL-1β increased secretion, hyperreactivity to PGF2α and cardiac remodelling. Conclusions We show that inhibition of NGF in vivo in a new rat model of severe PH partially reversed increased mPAP and cardiac remodelling. Moreover, our results show that NGF plays a role in various pathophysiological aspects of severe PH, and may therefore be of therapeutical interest in this disease.

Posters

Diabetic neuropathy (DNP) is a frequent and serious complication of diabetes mellitus (DM) that leads to progressive and length-dependent loss of peripheral nerve axons. The purpose of the present study is to assess the neuroprotective effects of levetiracetam (LEV) on DNP in a streptozotocin (STZ)-induced DM model in rats.Adult Sprague-Dawley rats were administered with STZ (60 mg/kg) to induce diabetes. DNP was confirmed by electromyography (EMG) and motor function test on 21st day following STZ injection. Study groups were assigned as follows; Group 1: Naïve control (n = 8), Group 2: DM + 1 mL/kg saline (n = 12), Group 3: DM + 300 mg/kg LEV (n = 10), Group 4: DM + 600 mg/kg LEV (n = 10). LEV was administered i.p. for 30 consecutive days. Then, EMG, motor function test, biochemical analysis (plasma lipid peroxides and total anti-oxidant capacity), histological and immunohistochemical analysis of sciatic nerves (TUNEL assay, bax, caspase 3, caspase 8 and NGF) were performed to evaluate the efficacy of LEV.Treatment of diabetic rats with LEV significantly attenuated the inflammation and fibrosis in sciatic nerves and prevented electrophysiological alterations. Immunohistochemistry of sciatic nerves showed a considerable increase in bax, caspase 3 and caspase 8 and a decrease in NGF expression in saline-treated rats whereas LEV significantly suppressed apoptosis markers and prevented the reduction in NGF expression. Besides, LEV considerably reduced plasma lipid peroxides and increased total anti-oxidant capacity in diabetic rats.The results of the present study suggest that LEV may have therapeutic effects in DNP through modulation of anti-oxidant and anti-apoptotic pathways.

Stromal–epithelial interaction study: The effect of corneal epithelial cells on growth factor expression in stromal cells using organotypic culture model

Interactions between stromal and epithelial cells play important roles in the development, homeostasis, and pathological conditions of the cornea. Soluble cytokines are critical factors in stromal–epithelial interactions, and growth factors secreted from corneal stromal cells contribute to the regulation of proliferation and differentiation of corneal epithelial cells (CECs). However, the manner in which the expression of growth factors is regulated in stromal cells has not been completely determined. To study stromal–epithelial cell interactions, we used an organotypic culture model. Human or rabbit CECs (HCECs or RCECs) were cultured on amniotic membranes placed on human corneal fibroblasts (HCFs) embedded in a collagen gel. The properties of the organotypic culture were examined by hematoxylin–eosin staining and immunofluorescence. In the organotypic culture, HCECs or RCECs were stratified into two–three layers after five days and five–seven layers after nine days. However, stratification was not observed when the HCECs were seeded on a collagen gel without fibroblasts. K3/K12 were expressed on day 9. The HCF-embedded collagen gels were collected on days 3, 5, or 9 after seeding the RCECs, and mRNA expression of growth factors FGF7, HGF, NGF, EGF, TGF-α, SCF, TGF-β1, TGF-β2, and TGF-β3 were quantified by real-time PCR. mRNA expression of the growth factors in HCFs cultured with RCECs were compared with those cultured without RCECs, as well as in monolayer cultures. mRNA expression of TGF-α was markedly increased in HCFs cultured with RCECs. However, mRNA expression of the TGF-β family was suppressed in HCFs cultured with RCECs. Principal component analysis revealed that mRNA expression of the growth factors in HCFs were generally similar when they were cultured with RCECs. In organotypic cultures, the morphological changes in the CECs and the expression patterns of the growth factors in the stromal cells clearly demonstrated stromal–epithelial cell interactions, and the results suggest that stromal cells and epithelial cells may act in concert in the cornea.

Nerve growth factor rescues diabetic mice heart after ischemia/reperfusion injury via up-regulation of the TRPV1 receptor

AimsNerve growth factor (NGF), a member of the neurotrophin family, plays an essential role in diabetic neuropathy and ischemic heart disease. In the present study, we explored the potential role of NGF and the involvement of TRPV1 receptor in isolated diabetic mouse hearts following ischemia/reperfusion (I/R) injury. MethodsAdenovirus-mediated NGF gene delivery was performed on diabetic and sham hearts 8weeks after streptozotocin treatment. The sciatic nerve conduction velocity was recorded using a biological signal acquisition system. Forty-eight hours after heart surgery, mice were subjected to I/R injury using a Langendorff system. Several cardiac parameters and the expression of associated molecules were analyzed during the experiment. ResultsThe sciatic nerve conduction velocity was reduced in diabetic mice compared with that in control mice. Decreased expression of NGF, TRPV1, and the downstream neurotransmitters CGRP and SP was observed in the diabetic hearts. Adenovirus-mediated NGF overexpression reversed the reduction in TRPV1 and downstream neuropeptides, resulting in improved cardiac recovery post-I/R injury in diabetic hearts. The protective effect of NGF was abolished by CGRP8-37 (a selective CGRP antagonist), while it was preserved by low-dose capsaicin. ConclusionsThe NGF-induced up-regulation of TRPV1 via the increased synthesis and release of endogenous CGRP leads to improved cardiac performance in I/R-injured diabetic heart.

Effects of pre- and postnatal deletion of the transcription factor NKx2-1 on the expression of NGF, trkA, trkB and p75NTR in mice

Background Expression of the homeodomain-containing transcription factor Nkx2-1 is essential for the prenatal development of the forebrain, lungs and thyroid gland. Humans with only one functioning NKX2-1-allele, a rare genetic condition known as “NKX2-1 haploinsufficiency”, become phenotypic in early childhood. This syndrome displays a variable combination of symptoms including congenital hypothyroidism, respiratory distress syndrome and choreoathetosis. The severity of the neurological symptoms varies between the patients but, however, little is known about the cell-types, which might be affected by the mutation. Recently it was shown in mice that cholinergic and parvalbumin (PV)containing GABAergic neurons of the subcortical basal ganglia and magnocellular nuclei of the ventral forebrain maintain Nkx2-1 synthesis throughout life. It is wellknown that postnatal cholinergic basal forebrain neurons are strongly influenced by the synthesis of neurotrophins including the “nerve growth factor” (NGF). For instance, NGF is essential for the differentiation and maintenance of these cells which otherwise, in the absence of this trophic molecule, undergo shrinkage and degeneration. It is also known that cortical GABAergic neurons, which are mostly described as their target cells, synthesize this factor. In order to elucidate whether impaired synthesis of Nkx2-1 is accompanied by corresponding effects on the neurotrophin synthesis, we have investigated conditional knock-out mice with either preor postnatal deletion of Nkx2-1. Additionally, we investigated the effects of these two mutations on the synthesis of corresponding neurotrophin receptors (trkA, trkB, p75NTR).

The effect of low-intensity laser therapy (LILT) on cutaneous wound healing and pain relief in rats.

[Purpose] This study examined the impact of low-intensity laser therapy on wound healing and pain control using a rat cutaneous wound model. [Subjects and Methods] Twenty-four adult male Sprague-Dawley rats (between 220−240 g, 7 weeks) were used in this study. The rats were anesthetized and a circular fragment of skin was removed from the dorsal region of the back by a punch with an 8-mm diameter. The animals were randomly divided into 6 groups, Groups C 1, C 3, and C 5, control groups, received no laser treatment. Groups T 1, T 3, and T 5 received laser treatment for 20 min per day for 1, 3 and 5 days, respectively. Lumbar spine and dorsal skin were extracted and processed using western blot analysis. [Results] Periodical observation showed increases in NGF expression on the skin, and decreases in c-fos expression by the spinal cord in the treatment groups compared to the control group. [Conclusion] The present findings suggest that low-intensity laser therapy could be used as an effective therapy for wound healing and pain relief, and could be further used as a clinical approach for treating cutaneous wounds.

Silencing p75NTR prevents proNGF-induced endothelial cell death and development of acellular capillaries in rat retina

Accumulation of the nerve growth factor precursor (proNGF) and its receptor p75NTR have been associated with several neurodegenerative diseases in both brain and retina. However, whether proNGF contributes to microvascular degeneration remain unexplored. This study seeks to investigate the mechanism by which proNGF/p75NTR induce endothelial cell (EC) death and development of acellular capillaries, a surrogate marker of retinal ischemia. Stable overexpression of the cleavage-resistant proNGF and molecular silencing of p75NTR were utilized in human retinal EC and rat retinas in vivo. Stable overexpression of proNGF decreased NGF levels and induced retinal vascular cell death evident by 1.9-fold increase in acellular capillaries and activation of JNK and cleaved-PARP that were mitigated by p75NTRshRNA. In vitro, overexpression of proNGF did not alter TNF-α level, reduced NGF, however induced EC apoptosis evident by activation of JNK and p38 MAPK, cleaved-PARP. Silencing p75NTR using siRNA restored expression of NGF and TrkA activation and prevented EC apoptosis. Treatment of EC with human-mutant proNGF induced apoptosis that coincided with marked protein interaction and nuclear translocation of p75NTR and the neurotrophin receptor interacting factor. These effects were abolished by a selective p75NTR antagonist. Therefore, targeting p75NTR represents a potential therapeutic strategy for diseases associated with aberrant expression of proNGF.

Expression of Leptin, NGF and Adiponectin in Metabolic Syndrome

Adipose tissue secretes a variety of adipokines involved in the regulation of energy metabolism and insulin resistance. Metabolic syndrome corresponds to a clinical condition in which white adipose tissue is characterized by an increased production and secretion of inflammatory molecules which may have local effects on adipose tissue physiology but also systemic effects on other organs. The aim of this study was to assess the expression of leptin, NGF and adiponectin in women with metabolic syndrome compared to healthy controls. Plasma leptin, NGF and adiponectin levels were measured by the ELISA method. Leptin and NGF immunohistochemical expression was analyzed in subcutaneous adipose tissue. The results indicated that in women with metabolic syndrome waist circumference, body mass index, HOMA index, glucose, total cholesterol and triglyceride levels were significantly increased in parallel with overxpressed plasma levels of leptin and NGF and decreased adiponectin. The immunohistochemical expression of leptin and NGF was very strong. In conclusion, this is the first study demonstrating a complex of immunochemical and immunohistochemical expression of the key adipokines including leptin, NGF and adiponectin in women with metabolic syndrome. Locally-produced pro-inflammatory adipokines probably contribute to the ethiopathogenic mechanisms ofmetabolic syndrome.

Effects of Icariside II on corpus cavernosum and major pelvic ganglion neuropathy in streptozotocin-induced diabetic rats.

Diabetic erectile dysfunction is associated with penile dorsal nerve bundle neuropathy in the corpus cavernosum and the mechanism is not well understood. We investigated the neuropathy changes in the corpus cavernosum of rats with streptozotocin-induced diabetes and the effects of Icariside II (ICA II) on improving neuropathy. Thirty-six 8-week-old Sprague-Dawley rats were randomly distributed into normal control group, diabetic group and ICA-II treated group. Diabetes was induced by a one-time intraperitoneal injection of streptozotocin (60 mg/kg). Three days later, the diabetic rats were randomly divided into 2 groups including a saline treated placebo group and an ICA II-treated group (5 mg/kg/day, by intragastric administration daily). Twelve weeks later, erectile function was measured by cavernous nerve electrostimulation with real time intracorporal pressure assessment. The penis was harvested for the histological examination (immunofluorescence and immunohistochemical staining) and transmission electron microscopy detecting. Diabetic animals exhibited a decreased density of dorsal nerve bundle in penis. The neurofilament of the dorsal nerve bundle was fragmented in the diabetic rats. There was a decreased expression of nNOS and NGF in the diabetic group. The ICA II group had higher density of dorsal nerve bundle, higher expression of NGF and nNOS in the penis. The pathological change of major pelvic nerve ganglion (including the microstructure by transmission electron microscope and the neurite outgrowth length of major pelvic nerve ganglion tissue cultured in vitro) was greatly attenuated in the ICA II-treated group (p < 0.01). ICA II treatment attenuates the diabetes-related impairment of corpus cavernosum and major pelvic ganglion neuropathy in rats with Streptozotocin-Induced Diabetes.

Expression of β-nerve growth factor and homeobox A10 in experimental cryptorchidism treated with exogenous nerve growth factor.

With the exception of standard inguinal orchidopexy, treatment of cryptorchidism with human chorionic gonadotropin has been performed for several years; however, its side effects have limited its application. The β‑nerve growth factor (NGF) and homeobox A10 (HoxA10) genes are closely associated with the development of the testes. To the best of our knowledge, whether exogenous NGF alters the endogenous levels of NGF and HoxA10 in cryptorchidism in rats remains to be elucidated. The aim of the present study was to evaluate the gene and protein expression of NGF and HoxA10 in experimental cryptorchidism following treatment with exogenous NGF. A unilateral mechanical cryptorchidism model in Sprague-Dawley rats was established and different concentrations of exogenous NGF were administered to observe the effects of NGF on cryptorchidism. Changes in the gene and protein expression levels of NGF and HoxA10 in the cryptorchid tissues of each group were identified using one step reverse transcription-quantitative polymerase chain reaction, in situ hybridization with digoxigenin‑labeled‑β‑NGF RNA probes, immunofluorescence and immunohistochemistry, respectively. The expression levels of NGF and HoxA10 were markedly higher in the group treated with a high dose of exogenous NGF compared with the group treated with a low dose of exogenous NGF and the group treated with human chorionic gonadotropin. These results confirmed the potential therapeutic effect of exogenous NGF in human cryptorchidism.

Mechanism of TiO2 nanoparticle-induced neurotoxicity in zebrafish (Danio rerio).

Zebrafish (Danio rerio) has been used historically for evaluating the toxicity of environmental and aqueous toxicants, and there is an emerging literature reporting toxic effects of manufactured nanoparticles (NPs) in zebrafish embryos. Few researches, however, are focused on the neurotoxicity on adult zebrafish after subchronic exposure to TiO2 NPs. This study was designed to evaluate the morphological changes, alterations of neurochemical contents, and expressions of memory behavior-related genes in zebrafish brains caused by exposures to 5, 10, 20, and 40 μg/L TiO2 NPs for 45 consecutive days. Our data indicated that spatial recognition memory and levels of norepinephrine, dopamine, and 5-hydroxytryptamine were significantly decreased and NO levels were markedly elevated, and over proliferation of glial cells, neuron apoptosis, and TiO2 NP aggregation were observed after low dose exposures of TiO2 NPs. Furthermore, the low dose exposures of TiO2 NPs significantly activated expressions of C-fos, C-jun, and BDNF genes, and suppressed expressions of p38, NGF, CREB, NR1, NR2ab, and GluR2 genes. These findings imply that low dose exposures of TiO2 NPs may result in the brain damages in zebrafish, provide a developmental basis for evaluating the neurotoxicity of subchronic exposure, and raise the caution of aquatic application of TiO2 NPs.

Treatment with ginseng total saponins improves the neurorestoration of rat after traumatic brain injury

Ethnopharmacological relevanceGinseng, the root of Panax ginseng C.A. Meyer, is a traditional medicinal herb that has been widely used in Asia for the treatment of many diseases through its effects of reinforcing vitality, strengthening the bodily resistance to pathogenic factors, engendering body liquids and allaying thirst, relieving uneasiness of the body and mind and benefiting intelligence, reducing body weight and prolonging life. Ginsenosides are the most important biologically active substances in ginseng. Many reports have suggested that ginsenosides could exert prominent neuroprotective and neurotrophic effects, promote neural stem/progenitor cell (NSC) proliferation and promote neurite outgrowth and neuronal network formation. The present study aimed to investigate whether treatment with ginsenosides could facilitate NSC proliferation in the hippocampal formation after traumatic brain injury (TBI) and contribute to the recovery of neurological functions including learning and memory. Materials and methodsThe modified Feeney׳s method was used to induce a TBI in rats. Ginseng total saponins (GTS) were treated intraperitoneally twice a day for 1 week after the TBI. The neurological functions, morphology of the hippocampus, expression of nerve growth-related factors and number of NSCs in the hippocampal formation ipsilateral to the trauma were determined. ResultsWe determined 1) GTS (5–80mg/kg) treatment after a TBI improved the recovery of neurological functions, including learning and memory, and reduced cell loss in the hippocampal area. The effects of GTS at 20, 40, 60, and 80mg/kg were better than the effects of GTS at 5 and 10mg/kg. 2) GTS treatment (20mg/kg) after a TBI increased the expression of NGF, GDNF and NCAM, inhibited the expression of Nogo-A, Nogo-B, TN-C, and increased the number of BrdU/nestin positive NSCs in the hippocampal formation. ConclusionsGTS treatment in rats after a TBI alleviated the secondary brain injury and ameliorated the neurological functions with an effective dose limit of 5–80mg/kg. GTS regulated the expression of nerve growth-related factors and improved the proliferation of neural stem/progenitor cells, which might facilitate neural regeneration and tissue repair, and might contribute to the recovery of neurological functions, including learning and memory. These effects of GTS might provide a foundation for the use of ginseng as a medicinal herb to enhance intelligence, reduce the aging process and prolong life in the traditional medicine.

Human endogenous retrovirus-K(II) envelope induction protects neurons during HIV/AIDS.

Human endogenous retroviruses (HERVs) are differentially expressed depending on the cell type and physiological circumstances. HERV-K has been implicated in the pathogenesis of several diseases although the functional consequences of its expression remain unknown. Human immunodeficiency virus (HIV) infection causes neuroinflammation with neuronal damage and death. Herein, we investigated HERV-K(II)/(HML-2) envelope (Env) expression and its actions in the brain during HIV/AIDS. HERV-K(II) Env expression was assessed in healthy brain tissues, autopsied HIV HIV− infected (HIV+) and uninfected (HIV−) brains and in neural cell cultures by real time RT-PCR, massively parallel (deep) sequencing, immunoblotting and immunohistochemistry. Neuronal and neural stem cells expressing HERV-K(II) Env were analyzed in assays of host responses including cellular viability, immune responses and neurobehavioral outcomes. Deep sequencing of human brain transcriptomes disclosed that RNA sequences encoded by HERV-K were among the most abundant HERV sequences detected in human brain. Comparison of different cell types revealed that HERV-K(II) env RNA abundance was highest in cultured human neurons but was suppressed by epidermal growth factor exposure. HERV-K(II) Env immunoreactivity was increased in the cerebral cortex from persons with HIV/AIDS, principally localized in neurons. Human neuronal cells transfected with HERV-K(II) Env exhibited increased NGF and BDNF expression. Expression of HERV-K(II) Env in neuronal cells increased cellular viability and prevented neurotoxicity mediated by HIV-1 Vpr. Intracerebral delivery of HERV-K(II) Env expressed by neural stem cells suppressed TNF-α expression and microglial activation while also improving neurobehavioral deficits in vpr/RAG1−/− mice. HERV-K(II) Env was highly expressed in human neurons, especially during HIV/AIDS, but in addition exerted neuroprotective effects. These findings imply that HERV gene products might exert adaptive effects in circumstances of pathophysiological stress, perhaps underlying the conservation of HERVs within the human genome.