Establishing a new model of cancer neuropathic pain in rats.

To guide the treatment of malignant neuropathic pain (MNP) in clinical practice, by inoculating MADB-106 breast cancer cells into the right L4 nerve root in Sprague-Dawley rats, a rat model of MNP was established, providing basic conditions for the study of neuropathic pain and development and application of therapeutic drugs. As the tumor grew over time, it pressed the nerve roots, causing nerve damage. The spinal nerve ligation (SNL) model, which is a neuropathic pain model widely used in rats, was compared with the L4 nerve root SNL model, and histologic examination of the nerve tissue of both models was performed by electron microscopy. In addition to the infiltration and erosion of the L4 nerve by tumor cells, the tumor tissue gradually grew and compressed the L4 nerve roots, resulting in hyperalgesia of the rat's posterior foot on the operative side. Some spontaneous pain phenomena were also observed, such as constant lifting or licking of the posterior foot on the operative side under quiet conditions. Electron microscopy images showed that nerve injury was due to progressive compression by the tumor, cells of which were visualized, but the injury was lighter than that in SNL rats. Imaging showed a paravertebral tumor near the L4 nerve root in the carcinomatous neuropathic pain model rat. These results suggest that progressive compression of the nerve by a malignant tumor leads to nerve damage similar to the behavioral changes associated with chronic compression injury resulting from a loose ligature of the nerve. The cancer neuropathologic pain model at the L4 nerve root was successfully established in Sprague-Dawley rats.

Climate warming promotes deterministic assembly of arbuscular mycorrhizal fungal communities.

Arbuscular mycorrhizal fungi (AMF) significantly contribute to plant resource acquisition and play important roles in mediating plant interactions and soil carbon (C) dynamics. However, it remains unclear how AMF communities respond to climate change. We assessed impacts of warming and precipitation alterations (30% increase or decrease) on soil AMF communities, and examined major ecological processes shaping the AMF community assemblage in a Tibetan alpine meadow. Our results showed that warming significantly increased root biomass, and available nitrogen (N) and phosphorus (P) in soil. While precipitation alterations increased AMF abundances, they did not significantly affect the composition or diversity of AMF communities. In contrast, warming altered the composition of AMF communities and reduced their Shannon-Wiener index and Pielou's evenness. In particular, warming shifted the AMF community composition in favor of Diversisporaceae over Glomeraceae, likely through its impact on soil N and P availability. In addition, AMF communities were phylogenetically random in the unwarmed control but clustered in warming plots, implying more deterministic community assembly under climate warming. Warming enhancement of root growth, N and P availability likely reduced plant C-allocation to AMF, imposing stronger environmental filtering on AMF communities. We further proposed a conceptual framework that integrates biological and geochemical processes into a mechanistic understanding of warming and precipitation changes' effects on AMF. Taken together, these results suggest that soil AMF communities may be more sensitive to warming than expected, highlighting the need to monitor their community structure and associated functional consequences on plant communities and soil C dynamics under the future warmer climate.

Beyond resource limitation: an expanded test of the niche dimension hypothesis for multiple types of niche axes.

The niche dimension hypothesis predicts that more species can coexist given a greater number of niche axes along which they partition the environment. Although this hypothesis has been broadly supported by nutrient enrichment experiments, its applicability to other ecological factors, such as natural enemies and abiotic stresses, has not been vigorously tested. Here, we examined the generality of the niche dimension hypothesis by experimentally manipulating both resource and non-resource niche dimensions-nitrogen limitation, pathogens and low-temperature stress-in a Tibetan alpine meadow. We found that decreases in niche dimensions led to a significant reduction in species richness, consistent with results from nutrient addition studies. However, different niche variables uniquely affected the plant communities. While nitrogen had largest effects on both community biomass and species richness, pathogens and low-temperature stress, in combination with nitrogen, had synergistic effects on them. Our results provide direct evidence demonstrating that both resource and non-resource niche dimensions can influence species coexistence. These findings suggest that other non-resource factors need to be taken into consideration to better predict the community assembly and control over biodiversity, particularly under the future multifaceted global change scenarios.

Chemoselective syntheses of spirodihydrofuryl and spirocyclopropyl barbiturates via cascade reactions of barbiturate-based olefins and acetylacetone.

The Michael addition initiated ring closure reaction of barbiturate-based olefins and acetylacetone with NBS has been explored. The efficient and chemoselective approach for the synthesis of barbiturate-fused spirocycles was established. Spirodihydrofuryl barbiturates and spirocyclopropyl barbiturates were synthesized selectively via cascade reactions under different basic conditions in moderate to excellent yields. The structure of 2-(4-chlorophenyl)-1,1-diacetyl-5,7-dimethyl-5,7-diazaspiro[2,5]octane-4,6,8-trione was confirmed by single crystal X-ray diffraction analysis.

Reconciling multiple impacts of nitrogen enrichment on soil carbon: plant, microbial and geochemical controls.

Impacts of reactive nitrogen (N) inputs on ecosystem carbon (C) dynamics are highly variable, and the underlying mechanisms remain unclear. Here, we proposed a new conceptual framework that integrates plant, microbial and geochemical mechanisms to reconcile diverse and contrasting impacts of N on soil C. This framework was tested using long-term N enrichment and acid addition experiments in a Mongolian steppe grassland. Distinct mechanisms could explain effects of N on particulate and mineral-associated soil C pools, potentially explaining discrepancies among previous N addition studies. While plant production predominated particulate C changes, N-induced soil acidification strongly affected mineral-associated C through decreased microbial growth and pH-sensitive associations between iron and aluminium minerals and C. Our findings suggest that effects of N-induced acidification on microbial respiration and geochemical properties should be included in Earth system models that predict ecosystem C budgets under future N deposition/input scenarios.

Enzymatic and Chemoenzymatic Syntheses of Disialyl Glycans and Their Necrotizing Enterocolitis Preventing Effects.

Necrotizing enterocolitis (NEC) is one of the most common and devastating intestinal disorders in preterm infants. Therapies to meet the clinical needs for this special and highly vulnerable population are extremely limited. A specific human milk oligosaccharide (HMO), disialyllacto-N-tetraose (DSLNT), was shown to contribute to the beneficial effects of breastfeeding as it prevented NEC in a neonatal rat model and was associated with lower NEC risk in a human clinical cohort study. Herein, gram-scale synthesis of two DSLNT analogs previously shown to have NEC preventing effect is described. In addition, four novel disialyl glycans have been designed and synthesized by enzymatic or chemoenzymatic methods. Noticeably, two disialyl tetraoses have been produced by enzymatic sialylation of chemically synthesized thioethyl ß-disaccharides followed by removal of the thioethyl aglycon. Dose-dependent and single-dose comparison studies showed varying NEC-preventing effects of the disialyl glycans in neonatal rats. This study helps to refine the structure requirement of the NEC-preventing effect of disialyl glycans and provides important dose-dependent information for using DSLNT analogs as potential therapeutics for NEC prevention in preterm infants.

Short-term cervical spinal cord stimulation for central post-stroke pain: a case report and literature review.

Introduction: Post-stroke central pain is disabling yet ineffectively treated with routine medical intervention. In this study, the authors presented an alternative neuromodulation therapy and conducted a brief narrative literature review to examine current evidence of spinal cord stimulation treatment for central post-stroke pain. Case presentation: Here, the authors reported a case of severe post-stroke syndrome, who achieved satisfactory improvement of pain symptom, as well as muscle rigidity with a novel neuromodulation therapy of short-term implantation of cervical spinal cord stimulation. Clinical discussion: It remains a great challenge in the management of post-stroke pain, which in turn significantly reduces the quality of life and worsens the burden on the public health system. Spinal cord stimulation therapy is an emerging neuromodulation approach to restore pathological pain status and functional impairment to provide a prospective insight into neuromodulation and rehabilitation options in the management of post-stroke syndrome. Conclusion: A potential role of spinal cord stimulation in the treatment of post-stroke pain is proposed in combined with traditional medication or other neuromodulation strategies, to achieve better control of pain in the future.

Why are graminoid species more dominant? Trait-mediated plant-soil feedbacks shape community composition.

Species traits may determine plant interactions along with soil microbiome, further shaping plant-soil feedbacks (PSFs). However, how plant traits modulate PSFs and, consequently, the dominance of plant functional groups remains unclear. We used a combination of field surveys and a two-phase PSF experiment to investigate whether forbs and graminoids differed in PSFs and in their trait-PSF associations. When grown in forb-conditioned soils, forbs experienced stronger negative feedbacks, while graminoids experienced positive feedbacks. Graminoid-conditioned soil resulted in neutral PSFs for both functional types. Forbs with thin roots and small seeds showed more-negative PSFs than those with thick roots and large seeds. Conversely, graminoids with acquisitive root and leaf traits (i.e., thin roots and thin leaves) demonstrated greater positive PSFs than graminoids with thick roots and tough leaves. By distinguishing overall and soil biota-mediated PSFs, we found that the associations between plant traits and PSFs within both functional groups were mainly mediated by soil biota. A simulation model demonstrated that such differences in PSFs could lead to a dominance of graminoids over forbs in natural plant communities, which might explain why graminoids dominate in grasslands. Our study provides new insights into the differentiation and adaptation of plant life-history strategies under selection pressures imposed by soil biota.

Gene silencing of NR2B-containing NMDA receptor by intrathecal injection of short hairpin RNA reduces formalin-induced nociception in C57BL/6 mouse.

Spinal NR2B-containing N-methyl-D-aspartate receptors (NR2B) play a critical role in the formation of central sensitization and persistent pain. Previous studies show that gene silencing of the spinal NR2B subunit by small interfering RNA (siRNA) could alleviate nociception in animals. The siRNA is a 19- to 23-nt RNA duplex, which can be synthesized in vitro or derived from short hairpin RNAs (shRNAs). In the present study, we investigated whether intrathecal injection of shRNAs targeting NR2B (GRIN2B shRNA) could affect nociception on formalin-induced pain in mice. Our results showed that intrathecal injection of GRIN2B shRNA could decrease NR2B mRNA and protein expression levels and hence effectively relieve formalin-induced nociception in mice, suggesting that intrathecal delivery of GRIN2B shRNA can be an efficient way to silence the target gene and provide new insights into the treatment of chronic pain.

Effect of perioperative intravenous flurbiprofen axetil on chronic postmastectomy pain.

OBJECTIVE: To explore whether perioperative intravenous flurbiprofen axetil can reduce the incidence and intensity of chronic pain for breast cancer after surgical treatment. METHODS: This randomized, double-blind, controlled trial enrolled 60 patients undergoing mastectomy and axillary lymph node dissection under general anesthesia. All patients accepted Hospital Anxiety and Depression Scale (HAD) tests the day before the surgery to evaluate depression and anxiety. The patients were randomly assigned to receive either 50 mg flurbiprofen axetil intravenously 15 minutes before the surgical incision and 6 hours later (group F) or intravenous 5 mL intralipid as a control (group C). All patients received patient-controlled intravenous analgesia (PCIA) with fentanyl postoperatively. Peripheral venous blood samples were drawn before the surgery, at 4 and 24 h after the surgery to detect the plasma level of PGE2 and tumor necrosis factor-α (TNF-α). Postoperative fentanyl consumption, Numerical Rating Scale (NRS) scores and adverse effects were recorded at 2, 6, 12, 24 and 48 h after the surgery. The duration and intensity of pain were followed up by telephone at the 2nd-12th month after the surgery. RESULTS: The incidence of pain at 2, 4, 6, and 12 months after the breast surgery was 33%, 20%, 15%, and 10%, respectively, and the average pain score was 0.77, 0.57, 0.28, and 0.18, respectively. Compared with group C, the scores of pain in group F were significantly lower at 2, 4, 6 and 12 months postoperatively (F=7.758, P=0.007). The incidence of pain in group F was significantly lower at 2, 4 and 6 months postoperatively (P<0.05). There was no significant difference in the incidence of pain between the groups at 12 months postoperatively (P>0.05). Preoperatively and at 4 and 24 h after the surgery, there was no significant difference in the level of TNF-α between the two groups (F=0.530, P=0.470); but plasma concentration of PGE2 in group F was significantly lower than that in group C (F=5.646, P=0.021). No patients developed abnormal bleeding, peptic ulcer, impaired liver or renal function and respiratory depression. CONCLUSION: Perioperative intravenous infusion of 100 mg flurbiprofen axetil can decrease the intensity and incidence of chronic pain for breast cancer after surgical treatment.

Photic sensitization is mediated by cortico-accumbens pathway in rats with trigeminal neuropathic pain.

Exposure to light stimuli may trigger or exacerbate perception of pain, also known as a common yet debilitating symptom of photophobia in patient with chronic orofacial pain. Mechanism underlying this phenomenon of photic sensitization in neuropathic condition remains elusive. Here, we found that rats developed hypersensitivity to normal light illumination after establishment of chronic constriction injury of infraorbital nerve (ION-CCI) model, which can be attenuated by blocking the exposure of photic stimulation. Additionally, this behavioral phenotype of light-sensitivity impairment was associated with overexpression of anterior cingulate cortex (ACC) c-fos positive neurons, enhancement of neural excitability in the ACC neurons and its excitatory synaptic transmission between nucleus accumbens (NAc). Optogenetic and chemogenic silencing of ACC-NAc pathway improved trigeminal sensitization in responses to light stimuli by decreasing spontaneous pain-like episodes in ION-CCI animals. In contrast, selective activation of ACC-to-NAc circuits enhanced photic hypersensitivity in dark environment. Thus, our data provided novel role of ACC and its projection to NAc in bidirectional modulation of photic sensation, which may contribute to the understanding of photic allodynia in trigeminal neuropathic pain status.

Plasma cell-free DNA 5-hydroxymethylcytosine and whole-genome sequencing signatures for early detection of esophageal cancer.

Esophageal cancer is a highly incidence and deadly disease with a poor prognosis, especially in developing countries. Owing to the lack of specific symptoms and early diagnostic biomarkers, most patients are diagnosed with advanced disease, leading to a 5-year survival rate of less than 15%. Early (n = 50) and middle-advanced (n = 50) esophageal squamous cell carcinoma (ESCC) patients, as well as 71 healthy individuals, underwent 5-hydroxymethylcytosine (5hmC) sequencing on their plasma cell-free DNA (cfDNA). A Northern Chinese cohort of cfDNA 5hmC dataset of 150 ESCC patients and 183 healthy individuals were downloaded for validation. A diagnostic model was developed using cfDNA 5hmC signatures and then improved by low-pass whole genome sequencing (WGS) features of cfDNA. Conserved cfDNA 5hmC modification motifs were observed in the two independent ESCC cohorts. The diagnostic model with 5hmC features achieved an AUC of 0.810 and 0.862 in the Southern and Northern cohorts, respectively, with sensitivities of 69.3-74.3% and specificities of 82.4-90.7%. The performance was well maintained in Stage I to Stage IV, with accuracy of 70-100%, but low in Stage 0, 33.3%. Low-pass WGS of cfDNA improved the AUC to 0.934 with a sensitivity of 82.4%, a specificity of 88.2%, and an accuracy of 84.3%, particularly significantly in Stage 0, with an accuracy up to 80%. 5hmC and WGS could efficiently differentiate very early ESCC from healthy individuals. These findings imply a non-invasive and convenient method for ESCC detection when clinical treatments are available and may eventually prolong survival.

Effects of linear-polarized near-infrared light irradiation on chronic pain.

In order to study the efficacy of linear-polarized near-infrared light irradiation (LPNIR) on relieving chronic pain in conjunction with nerve block (NB) or local block (LB), a 3-week prospective, randomized, double-blind, controlled study was conducted to evaluate the pre- and post-therapy pain intensity. Visual analogue scales (VASs) were measured in all patients before and 6 months after therapy visiting the pain clinic during the period of August 2007 to January 2008. A total of 52 patients with either shoulder periarthritis or myofascial pain syndrome or lateral epicondylitis were randomly assigned into two groups by drawing lots. Patients in Group I were treated with NB or LB plus LPNIR; Group II patients, for their part, were treated with the same procedures as in Group I, but not using LPNIR. In both groups, the pain intensity (VAS score) decreased significantly immediately after therapy as compared to therapy. There was a significant difference between the test and control groups immediately after therapy (P < 0.05), while no effect 6 months later. No side effects were observed. It is concluded that LPNIR is an effective and safe modality to treat various chronic pains, which has synergic effects with NB or LB.

[Changes of prostaglandin D2,carboxypeptidase A3 and platelet activating factor in guinea pig in anaphylactic shock].

OBJECTIVE: To detect the changes of leukotriene E4(LTE4), prostaglandin D2(PGD2), carboxypeptidase A3(CPA3) and platelet activating factor (PAF) in guinea pigs died from anaphylactic shock. METHODS: Guinea pigs were used for establishing anaphylactic shock models. The levels of LTE4, PGD2 and CPA3, and PAF were detected in urine, plasma, and brain tissues with ELISA kit, respectively. The significant biomarkers were selected comparing with control group. The changes of PGD2, CPA3 and PAF in the guinea pigs at time zero, 12 and 24 hours after death were observed and compared respectively. The effect of platelet activating factor acetylhydrolase (PAF-AH) to PAF in guinea pig brain was examined and compared. RESULTS: There were no statistically differences of LTE4 levels in urine observed between experimental group and control group. The levels of CPA3, PGD2 and PAF in the experimental group were significantly higher than that in the control group at 0 h. The levels of PAF at 12 and 24 hours after anaphylactic shock were significantly higher than that in the control group. The levels of PAF decreased significantly after pretreatment with PAF-AH. CONCLUSION: LTE4 in urine cannot be selected as a biomarker to determine the anaphylactic shock. PGD2 and CPA3 in plasma, and PAF in brain tissue may be used as biomarkers to determine the anaphylactic shock. PAF-AH may be potentially useful for clinical treatment of anaphylactic shock.

Repair Effects of Bone Marrow Mesenchymal Stem Cells on Demyelination of Trigeminal Ganglion in Rats with Trigeminal Neuralgia.

OBJECTIVE: The current study investigated the effects of bone marrow mesenchymal stem cells (BMSCs) on pain behavior in rats with trigeminal neuralgia induced by infraorbital nerve chronic constriction injury (ION-CCI), and the repair effects of BMSCs on pathological changes in trigeminal ganglion demyelination. METHODS: BMSCs or phosphate-buffered saline (PBS) alone were injected around trigeminal ganglion in ION-CCI rats via a rat brain stereotaxic apparatus. Mechanical pain threshold (von Frey test) and face grooming behavior were measured in each group. Recovery of demyelination of trigeminal ganglion was observed via electron microscopy 2 weeks later, and BMSC differentiation was observed via immunofluorescence. RESULTS: Rats in the BMSC group exhibited significant improvements in mechanical pain threshold and face grooming behavior compared with the PBS group. BMSCs could repair demyelinating changes in trigeminal ganglion in ION-CCI rats. Only cells expressing GFAP, S-100, and p75 were observed via immunofluorescence, and no PKH67-labeled BMSCs were observed in the trigeminal ganglion. No BMSC differentiation was observed in the trigeminal ganglion. CONCLUSION: Injection of BMSCs around the trigeminal ganglion could relieve trigeminal neuralgia effectively and repair trigeminal ganglion demyelination. No differentiation of BMSCs injected around the trigeminal ganglion into Schwann cells was observed. The mechanism of trigeminal neuralgia demyelination repair requires further investigation.

A novel implantable device for sensory and affective assessment of orofacial pain in rats.

Background and objective: Orofacial pain, in particular, chronic orofacial pain remains a great challenge in clinical practice. To better understand the underlying mechanism of disease, it is essential to apply a feasible and stable preclinical measurement of facial pain. Here, we introduced a novel electrical noxious stimulator in freely behavioral rodents and examined its validation in both naïve and chronic orofacial pain animals. Methods: One subcutaneous device of electrical stimulator was implanted in the facial region for delivery of the nociceptive input. The sensory component of orofacial pain was assessed by response scoring tool, and conditioned place aversion (CPA) paradigm for pain affect respectively. To confirm its usage in chronic pain state, the chronic constriction injury of the infraorbital nerve (ION-CCI) model was then applied. Results: We found that responsive scores increased with stimulation intensity, and acted in a dosage-dependent manner, which can be attenuated by the administration of morphine intraperitoneally. Naïve rats displayed significant aversive reaction to the noxious electrical stimulation (25V) in the CPA testing. In addition, an obvious sensory hypersensitivity to electrical stimulation was confirmed by the increased response scores in ION-CCI rats. Furthermore, ION-CCI animal showed significant avoidance to electrical stimulation at relatively low intensity (10V), which was innoxious to naïve rats. Conclusion: Our findings may provide an alternative pre-clinical measurement of orofacial pain, to quantitively assess both sensory and affective component of orofacial pain.

A Patient With a Foreign Body in Mediastinum That Penetrated Into the Bronchus.

We report the rare case of a patient who had a foreign body in the mediastinum and trachea caused by trauma due to epileptic seizures. A 52-year-old man had an epileptic seizure 3 months before visiting our hospital and had an injury to his neck caused by a broken glass cabinet. Computed tomography scan revealed a foreign body in the mediastinum and trachea. After a detailed discussion among members of the multidisciplinary team, surgery was successfully performed to remove the foreign body. This rare case may help provide a reference for diagnosing and treating a mediastinal and tracheobronchial foreign body.

Clinical Outcome of Pulsed-Radiofrequency Combined With Transforaminal Epidural Steroid Injection for Lumbosacral Radicular Pain Caused by Distinct Etiology.

BACKGROUND: Lumbosacral radicular pain (LSRP) can be caused by disc herniation, spinal stenosis, and failed back surgery syndrome. The clinical effect of pulsed-radiofrequency (PRF) combined with transforaminal epidural steroid injection (TESI) for radiating pain in different population remains unclear. METHODS: We retrospectively reviewed the medical recordings of patients with LSRP caused by different etiologies, who underwent PRF and TESI treatment. The primary clinical outcome was assessed by a 10-point Visual Analog Scale (VAS) pre- and post-treatment. RESULTS: A total of 34 LSRP patients were identified and classified into 3 subgroups (disc herniation, spinal stenosis, and failed back surgery syndrome). The overall immediate pain reduction was 4.4 ± 1.1 after procedure. After a median follow-up of 9.5 months, the VAS decreased from 6.5 ± 1.0 to 2.4 ± 1.9 at the last follow-up. CONCLUSION: PRF combined with TESI is an effective approach to treat persistent LSRP in distinct population.

Toll-like receptor 4-myeloid differentiation factor 88 signaling contributes to ventilator-induced lung injury in mice.

BACKGROUND: The mechanisms of ventilator-induced lung injury, an iatrogenic inflammatory condition induced by mechanical ventilation, are not completely understood. Toll-like receptor 4 (TLR4) signaling via the adaptor protein myeloid differentiation factor 88 (MyD88) is proinflammatory and plays a critical role in host immune response to invading pathogen and noninfectious tissue injury. The role of TLR4-MyD88 signaling in ventilator-induced lung injury remains incompletely understood. METHODS: Mice were ventilated with low or high tidal volume (HTV), 7 or 20 ml/kg, after tracheotomy for 4 h. Control mice were tracheotomized without ventilation. Lung injury was assessed by: alveolar capillary permeability to Evans blue albumin, wet/dry ratio, bronchoalveolar lavage analysis for cell counts, total proteins and cytokines, results of histopathological examination of the lung, and plasma cytokine levels. RESULTS: Wild-type mice subjected to HTV had increased pulmonary permeability, inflammatory cell infiltration/lung edema, and interleukin-6/macrophage-inflammatory protein-2 in the lavage compared with control mice. In HTV, levels of inhibitor of kappaB alpha decreased, whereas phosphorylated extracellular signal-regulated kinases increased. TLR4 mutant and MyD88 mice showed markedly attenuated response to HTV, including less lung inflammation, pulmonary edema, cell number, protein content, and the cytokines in the lavage. Furthermore, compared with wild-type mice, both TLR4 mutant and MyD88 mice had significantly higher levels of inhibitor of kappaB alpha and reduced extracellular signal-regulated kinase phosphorylation after HTV. CONCLUSIONS: TLR4-MyD88 signaling plays an important role in the development of ventilator-induced lung injury in mice, possibly through mechanisms involving nuclear factor-kappaB and mitogen-activated protein kinase pathways.

[Expression of NR2B in the spinal dorsal horn and dorsal root ganglia in mice with bone cancer pain].

OBJECTIVE: To investigate the manifestation of ethology and the immunohistochemistry results of the 2B Subunits of N-methyl-D-aspartate receptors (NR2B) in the spinal cord dorsal horn and dorsal root ganglia (DRG) in mice with bone cancer pain and their correlation, and to discuss the role of NR2B in the generation and maintenance of bone cancer pain. METHODS: Forty-five male C57BL/6 mice were randomly divided into 3 groups: a model group (n=15), 2×10(6) cells in 10 µL D-Hank's were injected into the left femur of mice;a sham group(n=15), only 10 µL D-Hank's injected into the left femur of mice;and a normal control group(n=15), no treatment. Spontaneous lifting duration and mechanical withdrawal threshold of the hind paw of mice were measured on alternative days throughout the experiment. Bones from 5 mice in each group were stained with HE on Day 7, 15, and 23 after the inoculation and segments of lumbar spinal cord and L(4) DRG were taken to detect NR2B by immunohistochemistry. RESULTS: Bone cancer pain models were successfully established and confirmed by ethology and histology. The immunohistochemical positive indexes of NR2B were significantly higher in the model group than in the sham group and the control group. In the model group there were obvious differences either between Day 7 and Day 15, or between Day 7 and Day 23 (P<0.05). On Day 23, the immunohistochemical positive indexes of NR2B in the ipsilateral spinal cord dorsal horn of all groups, and L(4) DRG were positively correlated with the spontaneous lifting duration of ipsilateral hindpaw (r=0.976, P<0.001; r=0.882, P<0.001, respectively), negatively correlated with the mechanical withdrawal threshold of ipsilateral hindpaw (r=-0.879, P<0.001; r=-0.760, P=0.001, respectively). CONCLUSION: The immunohistochemical positive indexes of NR2B are increased and significantly correlated with the manifestation of ethology. NR2B in the spinal cord and L(4) DRG may participate and mediate in forming and developing hyperalgesia in bone cancer pain.