Cardiac Arrhythmia Risk after Anti-Cancer Drug Exposure and Related Disease Molecular Imaging Outlook: A Systematic Review, Meta-Analysis, and Network Meta-Analysis.

BACKGROUND: Chemotherapy is the main first-line treatment, but there is a problem of adverse reactions to systemic drugs. Chemotherapeutic agents may cause adverse effects on the body, influencing the prognosis. Whether the clinical application of anthracyclines is associated with an increased arrhythmic risk remains controversial. To evaluate the arrhythmic risk of anthracyclines as a class, and the comparative risk for each drug, we conducted a systematic review, meta-analysis, and network meta-analysis. METHODS: PubMed, Web of Science, EMBASE, and the Cochrane Library were searched, up to March 2022, for randomized controlled trials, cohort studies, and case-control studies that investigated the association between anthracyclines treatment and the risk of arrhythmia. We followed the PRISMA 2020 guidelines for data selection and extraction. Outcomes were pooled using fixed effects models in cohort studies and randomized controlled studies, and random models in single-arm studies. Direct and indirect comparisons in network meta-analysis were performed using frequentist methods. RESULTS: In total, 4 cohort studies, 8 RCTs, and 18 single-arm studies were included in our analysis. Anthracyclines' use was associated with a statistically significant 90% increase in the risk of arrhythmia (odds ratio [OR] 1.90; 95% confidence interval [CI] 1.62-2.24) and a 114% increase in the risk of supraventricular arrhythmia (OR 2.14; 95% CI 1.18-3.89). And the single-arm studies also indicated that the incidence of arrhythmia rate is 20% and the 95% CI is 15/100-25/100. Epirubicin ranked most likely to have the highest risk of arrhythmia compared with non-anthracycline antineoplastic drugs in the analysis (OR 43.07 [95% CI 2.80-2105.83]) by network meta-analysis. CONCLUSIONS: Our findings show a significant association between anthracyclines' use and an increased risk of arrhythmia, especially supraventricular arrhythmia. Epirubicin ranked with the highest probability of arrhythmia. These results indicated that cardiac rhythm should be strictly monitored during the application of anthracyclines in clinical practice, and a possible therapy for anthracycline-associated arrhythmia should be explored. Molecular imaging technology is an important means to study the mechanism of drug action on cardiac electrophysiology in the future. By imaging molecular targets in cardiac cells, the effects of drugs on the electrophysiological properties of cardiac cells can be understood, which provides information for the development of safer and more effective drugs.

Elucidating Iron Metabolism through Molecular Imaging.

Iron is essential for many physiological processes, and the dysregulation of its metabolism is implicated in the pathogenesis of various diseases. Recent advances in iron metabolism research have revealed multiple complex pathways critical for maintaining iron homeostasis. Molecular imaging, an interdisciplinary imaging technique, has shown considerable promise in advancing research on iron metabolism. Here, we comprehensively review the multifaceted roles of iron at the cellular and systemic levels (along with the complex regulatory mechanisms of iron metabolism), elucidate appropriate imaging methods, and summarize their utility and fundamental principles in diagnosing and treating diseases related to iron metabolism. Utilizing molecular imaging technology to deeply understand the complexities of iron metabolism and its critical role in physiological and pathological processes offers new possibilities for early disease diagnosis, treatment monitoring, and the development of novel therapies. Despite technological limitations and the need to ensure the biological relevance and clinical applicability of imaging results, molecular imaging technology's potential to reveal the iron metabolic process is unparalleled, providing new insights into the link between iron metabolism abnormalities and various diseases.

Impaired neuronal macroautophagy in the prelimbic cortex contributes to comorbid anxiety-like behaviors in rats with chronic neuropathic pain.

A large proportion of patients with chronic pain experience co-morbid anxiety. The medial prefrontal cortex (mPFC) is proposed to underlie this comorbidity, but the molecular and neuronal mechanisms are not fully understood. Here, we reported that impaired neuronal macroautophagy in the prelimbic cortical (PrL) subregion of the mPFC paralleled the occurrence of anxiety-like behaviors in rats with chronic spared nerve injury (SNI). Intriguingly, such macroautophagy impairment was mainly observed in a FOS/c-Fos+ neuronal subpopulation in the PrL. Chemogenetic inactivation of this comorbid anxiety-related neuronal ensemble relieved pain-induced anxiety-like behaviors. Rescuing macroautophagy impairment in this neuronal ensemble relieved chronic pain-associated anxiety and mechanical allodynia and restored synaptic homeostasis at the molecular level. By contrast, artificial disruption of macroautophagy induced early-onset co-morbid anxiety in neuropathic rats, but not general anxiety in normal rats. Taken together, our work identifies causal linkage between PrL neuronal macroautophagy dysfunction and comorbid anxiety in neuropathic pain and provides novel insights into the role of PrL by differentiating its contribution in pain-induced comorbid anxiety from its modulation over general anxiety-like behaviors.Abbreviation: AAV: adeno-associated viruses; ACC: anterior cingulate cortex; ATG5: autophagy related 5; ATG7: autophagy related 7; ATG12: autophagy related 12; CAMK2/CaMKII: calcium/calmodulin-dependent protein kinase II; CNO: clozapine-N-oxide; CQ: chloroquine; DIA: data independent acquisition; DIO: double floxed inverse orf; DLG4/PSD-95: discs large MAGUK scaffold protein 4; Dox: doxycycline; GABA: γ-aminobutyric acid; GFP: green fluorescent protein; GO: gene ontology; Gi: inhibitory guanine nucleotide-binding proteins; HsCHRM4/M4D: human cholinergic receptor muscarinic 4; HsSYN: human synapsin; KEGG: Kyoto encyclopedia of genes and genomes; LAMP1: lysosomal-associated membrane protein 1; LC3-II: PE conjugated microtubule-associated protein 1 light chain3; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; mPFC: medial prefrontal cortex; P2A: 2A self-cleaving peptide; PPI: protein-protein interaction networks; PrL: prelimbic cortex; RBFOX3/NeuN: RNA binding protein, fox-1 homolog (C. elegans) 3; rtTA: reverse tetracycline-transactivator; SDS-PAGE: sodium dodecylsulfate-polyacrylamide gel electrophoresis; SHANK3: SH3 and multiple ankyrin repeat domains 3; SLC1A1/EAAC1: solute carrier family 1 (neuronal/epithelial high affinity glutamate transporter, systemXag), member 1; SNAP23: synaptosomal-associated protein 23; SNI:spared nerve injury; SQSTM1/p62: sequestosome 1; SYT3: synaptotagmin 3; TRE: tetracycline-responsive element; TRE3G: third-generation tetracycline-responsive element.

Engineering the Staple Oil Crop Brassica napus Enriched with α-Linolenic Acid Using the Perilla FAD2-FAD3 Fusion Gene.

Modern people generally suffer from α-linolenic acid (ALA) deficiency, since most staple food oils are low in ALA content. Thus, the enhancement of ALA in staple oil crops is of importance. In this study, the FAD2 and FAD3 coding regions from the ALA-king species Perilla frutescens were fused using a newly designed double linker LP4-2A, driven by a seed-specific promoter PNAP, and engineered into a rapeseed elite cultivar ZS10 with canola quality background. The mean ALA content in the seed oil of PNAP:PfFAD2-PfFAD3 (N23) T5 lines was 3.34-fold that of the control (32.08 vs 9.59%), with the best line being up to 37.47%. There are no significant side effects of the engineered constructs on the background traits including oil content. In fatty acid biosynthesis pathways, the expression levels of structural genes as well as regulatory genes were significantly upregulated in N23 lines. On the other hand, the expression levels of genes encoding the positive regulators of flavonoid-proanthocyanidin biosynthesis but negative regulators of oil accumulation were significantly downregulated. Surprisingly, the ALA level in PfFAD2-PfFAD3 transgenic rapeseed lines driven by the constitutive promoter PD35S was not increased or even showed a slight decrease due to the lower level of foreign gene expression and downregulation of the endogenous orthologous genes BnFAD2 and BnFAD3.

Correlation between expression of Lin28B and C-myc in patients with laryngeal squamous cell carcinoma and clinicopathological features and prognosis. / Lin28B和C-mycè›‹ç™½åœ¨å–‰é³žç™Œä¸­çš„è¡¨è¾¾åŠå ¶ä¸Žä¸´åºŠç— ç†ç‰¹å¾å’Œé¢„åŽçš„ç›¸å ³æ€§.

OBJECTIVES: Laryngeal squamous cell carcinoma (LSCC) is a common malignant tumor of head and neck. Screening of target genes for malignant tumor therapy is one of the focuses of cancer research, with proto-oncogene and tumor suppressor gene as the breakthrough. It has become an urgent need to find the target gene related to the treatment and prognosis of LSCC.This study aims to explore the role of Lin28B and C-myc in LSCC by detecting the expressions of these two proteins and analyze the correlation between the expression of Lin28B and C-myc and clinicopathological features and prognosis of LSCC. METHODS: We detected the expression of Lin28B and C-myc proteins in 102 specimens of LSCC and 90 specimens of adjacent tissues by immunochemistry, and analyzed the correlation between Lin28B and C-myc protein expressions in LSCC as well as the correlation between the expressions of the two proteins and the clinicopathological features of LSCC. At the same time, the Kaplan-Meier method was used to analyze the relation between Lin28B and C-myc protein levels with the postoperative survival rate of LSCC patients. RESULTS: The protein levels of Lin28B and C-myc in the LSCC tissnes were significantly higher than those in the adjacent tissues (both P<0.05),and there was a positive correlation between the expression of Lin28B and C-myc in LSCC (r＝0.476, P<0.05). The expression of Lin28B protein was closely related to age, lymph node metastasis, clinical stage, tumor size, and pathological differentiation of LSCC patients (all P<0.05). while the expression of C-myc protein was closely related to lymph node metastasis, clinical stage, tumor size, and pathological differentiation of LSCC patients (all P<0.05). A relevant survival analysis showed that in patients with higher level of Lin28B (P＝0.001) or C-myc protein (P<0.001), the postoperative survival rate was relatively low. CONCLUSIONS: Lin28B and C-myc proteins are highly expressed in LSCC with a positive correlation. Furthermore, they are closely related to lymph node metastasis, clinical stage, tumor size, pathological differentiation and prognosis, suggesting that both Lin28B and C-myc might be involved in the occurrence and development of LSCC.

Genetic profile identification and clinicopathologic characteristics analysis of the thyroid-like low-grade nasopharyngeal papillary adenocarcinoma.

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is an extremely rare malignancy bearing histomorphological similarities to papillary thyroid carcinoma with good prognosis. It's important to distinguish TL-LGNPPA from other papillary tumors including nasopharyngeal papillary adenocarcinoma (NPPA), metastatic and ectopic papillary thyroid cancer, and metastasized adenocarcinomas, etc. To date, only 48 cases of TL-LGNPPA have been reported in the English literatures. Here, we reported the genomic characteristics of additional 4 cases and reviewed other reports to clarify the clinicopathological features of this tumor. In this study, 41 mutations were detected by whole-exome sequencing, but no typical driver mutations were found. Two sample with Copy Number Variations (CNV) were found (7 q22. 17 q12), of which the segment spanned the regions of RASA4, POLR2J2, SPDYE2, CCL3, CCL4, etc. Additionally, no MSI and HLA LOH were found. To our knowledge, we are the first to reveal the genetic underpinnings of this rare tumor. The clinicopathological features of TL-LGNPPA were characterized, shedding more light on the essential difference between TL-LGNPPA with other papillary tumors.

Overexpression of KIAA1199 is an independent prognostic marker in laryngeal squamous cell carcinoma.

BACKGROUND: KIAA1199 is a recently identified novel gene that is upregulated in various human cancers with poor survival, but its role and the underlying mechanisms in laryngeal squamous cell carcinoma (LSCC) remain unknown. Here, we collected tissues from 105 cases of LSCC to investigate the relationships between KIAA1199 protein expression and clinical factors. METHODS: Western blotting and real-time quantitative PCR (RT-PCR) were used for detect the protein and mRNA expression of KIAA1199 in LSCC tissue. Immunohistochemistry (IHC) staining was used to detect the expression of KIAA1199. Patient clinical information, for instance sex, age, pathological differentiation, clinical region, T stage, N stage, clinical stage, operation type, neck lymph dissection, smoking status, and drinking status were recorded. Kaplan-Meier survival analysis and Cox analysis were applied to identify the relationship between KIAA1199 and LSCC. RESULTS: Western blotting results showed KIAA1199 protein was significantly higher in tumor tissues vs. adjacent non-cancerous tissues (0.9385 ± 0.1363 vs. 1.838 ± 0.3209, P = 0.04). The KIAA1199 mRNA expression was considerably higher in tumor tissues (P < 0.001) than in adjacent non-cancerous tissues by RT-PCR. IHC results showed up-regulated KIAA1199 expression was related with some severe clinicopathological parameters: pathologic differentiation (P = 0.002), T stage (P < 0.001), N stage (P < 0.001), clinical stage (P < 0.001), survival time (P = 0.008) and survival status (P < 0.001). Kaplan-Meier survival analysis showed that patients with high KIAA1199 protein expression had poor overall survival (OS) (P < 0.05). Cox analysis suggested that the KIAA1199 protein expression constituted an independent prognostic marker for LSCC patients (P < 0.001). CONCLUSION: Our findings revealed that KIAA1199 protein expression may be used to predict LSCC patient outcome.

Development of a CRISPR-SaCas9 system for projection- and function-specific gene editing in the rat brain.

A genome editing technique based on the clustered regularly interspaced short palindromic repeats (CRISPR)-associated endonuclease Cas9 enables efficient modification of genes in various cell types, including neurons. However, neuronal ensembles even in the same brain region are not anatomically or functionally uniform but divide into distinct subpopulations. Such heterogeneity requires gene editing in specific neuronal populations. We developed a CRISPR-SaCas9 system-based technique, and its combined application with anterograde/retrograde AAV vectors and activity-dependent cell-labeling techniques achieved projection- and function-specific gene editing in the rat brain. As a proof-of-principle application, we knocked down the cbp (CREB-binding protein), a sample target gene, in specific neuronal subpopulations in the medial prefrontal cortex, and demonstrated the significance of the projection- and function-specific CRISPR-SaCas9 system in revealing neuronal and circuit basis of memory. The high efficiency and specificity of our projection- and function-specific CRISPR-SaCas9 system could be widely applied in neural circuitry studies.

Upregulation of interleukin-6 on Cav3.2 T-type calcium channels in dorsal root ganglion neurons contributes to neuropathic pain in rats with spinal nerve ligation.

The T-type calcium channels Cav3.2, one of the low voltage-activated (LVA) calcium channels, have been found to play important roles in the neuronal excitability. Recently, we and others have demonstrated that accumulation of Cav3.2 channels in the dorsal root ganglion (DRG) neurons and sensory nerves contributes to neuropathic pain after peripheral nerve injury. In the present study, we aimed to further investigate the regulation of Cav3.2 channels by interleukin-6 (IL-6) in DRG neurons in neuropathic pain rats after spinal nerve ligation (SNL). The results showed that Cav3.2 channel protein expression in L5 DRG neurons was upregulated and blockade of this channel decreased the hyperexcitability of DRG neurons and mechanical allodynia in SNL neuropathic pain rats. Furthermore, inhibition of IL-6 trans-signaling reduced the upregulation of Cav3.2 T-type channel induced by FIL-6 (a fusion protein of IL-6 and sIL-6R) in primary cultured DRG neurons in vitro. In vivo, inhibition of IL-6 trans-signaling reversed the upregulation of Cav3.2, reduced the hyperexcitability of L5 DRG neurons and alleviated mechanical allodynia in SNL rats. Our results suggest that IL-6 upregulates Cav3.2 T-type channels expression and function through the IL-6/sIL-6R trans-signaling pathway in DRG neurons, thus contributes to the development of neuropathic pain in SNL rats.

Chia (Salvia hispanica) experiment at a 30˚ N site in Sichuan Basin, China / Performance agronômica da chia (Salvia hispanica) cultivada aos 30˚ N na Bacia de Sichuan, China

ABSTRACT: The mysterious ancient Mesoamerican Indian crop chia (Salvia hispanica) is revived and expanding worldwide due to its richness of valuable nutraceuticals such as α-linolenic acid (ALA), antioxidants, food fiber, gels, and proteins. We carried out a pilot experiment on chia planting in non-frost Sichuan Basin, at Hechuan Base (30˚0′ 43″ N, 106˚7′ 41″ E, 216 m), Southwest University, Chongqing, China. The split-plot trial contained two factors, 3 spring-summer sowing times as main plots, and 6 densities as subplots, with 3 replicates. Phenological, botanical, adversity, yield, and seed quality traits were investigated. Plants were very tall, suffered from lodging, and flowered in mid-October. Sichuan Basin can be considered as a north edge for growing chia, with low yield (680 kg/hectare) because of insufficient seed filling and maturation in autumn-winter season (1000-seed weight of 1.14 g). However, its ALA content is 5 percent points higher than the seed-donor commercial bottle (65.06%/63.96% VS 59.35%/59.74% for black/white seeds), accompanied by decrease oleic and stearic acid, while linoleic acid and palmitic acid are equivalent. Considering its short-day habit, it is recommended to try sowing in middle summer (from late June to early August) to avoid too long growing period, excessive vegetative growth, and waste of field and climate resources caused by spring-summer sowing. Furthermore, winter sowing of chia with mulch cover could also be tried, with an expectation of harvesting in summer. Most importantly, only when the photoperiod-insensitive early flowering stocks are created, chia can be recommended as a low-risk crop to the farmers of this region.

RESUMO: A chia (Salvia hispanica) é cultivada em todo o mundo por sua riqueza de nutrientes nutracêuticos valiosos, tais como a-ácido linolênico (ALA), antioxidantes, fibras alimentares, géis e proteínas. Entretanto, não há informações sobre sua performance agronômica se cultivada aos 30˚N na China. Assim, realizou-se um experimento com o cultivo de chia na base Hechuan (30°0'43"N, 106°7'41"E, 216m, que não apresenta geada) da Southwest University, Chongqing, China. O delineamento em parcela subdividida contém dois fatores,três épocas de semeadura na primavera-verão como parcelas principais e seis densidades de sementes como subparcelas, com três repetições. Foram investigados os caracteres fenológicos, botânicos, de adversidade, rendimento e qualidade da semente. As plantas se tornaram altas, acamarame floresceram em meados de outubro. A bacia de Sichuan pode ser considerada como uma fronteira limítrofe norte para o crescimento da chia, com baixo rendimento (680kg ha-1) devido ao enchimento e amadurecimento insuficientes na estação outono-inverno (peso de 1000 sementes de 1,14g). No entanto, o seu conteúdo de ALA é de 5 pontos percentuais mais elevado do que a semente comercial, 65,06%/63,96% contra 59,35%/59,74% para as sementes pretas/brancas, respectivamente, acompanhado por diminuição de ácido oleico e ácido esteárico, enquanto que o ácido linoleico e o ácido palmítico são equivalentes. Considerando o seu hábito de dia curto, recomenda-se semear no meio do verão,de junho a início de agosto, para evitar um tempo de cultivo muito longo, desenvolvimento vegetativo excessivo e desperdício de recursos de campo e clima causados pela semeadura de primavera-verão. Além disso, a semeadura de inverno da chia com cobertura morta também poderia ser realizada, com expectativa de colheita no verão. Mais importante ainda, somente quando os estoques de floração precoce insensíveis ao fotoperíodo são criados, pode-se recomendar como uma cultura de baixo risco para os agricultores desta região.

Shp-1 dephosphorylates TRPV1 in dorsal root ganglion neurons and alleviates CFA-induced inflammatory pain in rats.

Transient receptor potential vanilloid 1 (TRPV1) receptors are expressed in nociceptive neurons of rat dorsal root ganglions (DRGs) and mediate inflammatory pain. Nonspecific inhibition of protein-tyrosine phosphatases (PTPs) increases the tyrosine phosphorylation of TRPV1 and sensitizes TRPV1. However, less is known about tyrosine phosphorylation's implication in inflammatory pain, compared with that of serine/threonine phosphorylation. Src homology 2 domain-containing tyrosine phosphatase 1 (Shp-1) is a key phosphatase dephosphorylating TRPV1. In this study, we reported that Shp-1 colocalized with and bound to TRPV1 in nociceptive DRG neurons. Shp-1 inhibitors, including sodium stibogluconate and PTP inhibitor III, sensitized TRPV1 in cultured DRG neurons. In naive rats, intrathecal injection of Shp-1 inhibitors increased both TRPV1 and tyrosine-phosphorylated TRPV1 in DRGs and induced thermal hyperalgesia, which was abolished by pretreatment with TRPV1 antagonists capsazepine, BCTC, or AMG9810. Complete Freund's adjuvant (CFA)-induced inflammatory pain in rats significantly increased the expression of Shp-1, TRPV1, and tyrosine-phosphorylated TRPV1, as well as the colocalization of Shp-1 and TRPV1 in DRGs. Intrathecal injection of sodium stibogluconate aggravated CFA-induced inflammatory pain, whereas Shp-1 overexpression in DRG neurons alleviated it. These results suggested that Shp-1 dephosphorylated and inhibited TRPV1 in DRG neurons, contributing to maintain thermal nociceptive thresholds in normal rats, and as a compensatory mechanism, Shp-1 increased in DRGs of rats with CFA-induced inflammatory pain, which was involved in protecting against excessive thermal hyperalgesia.

Lysine-specific demethylase 1 in breast cancer cells contributes to the production of endogenous formaldehyde in the metastatic bone cancer pain model of rats.

BACKGROUND: Bone cancer pain seriously affects the quality of life of cancer patients. Our previous study found that endogenous formaldehyde was produced by cancer cells metastasized into bone marrows and played an important role in bone cancer pain. However, the mechanism of production of this endogenous formaldehyde by metastatic cancer cells was unknown in bone cancer pain rats. Lysine-specific demethylase 1 (LSD1) is one of the major enzymes catalyzing the production of formaldehyde. The expression of LSD1 and the concentration of formaldehyde were up-regulated in many high-risk tumors. OBJECTIVE: This study aimed to investigate whether LSD1 in metastasized MRMT-1 breast cancer cells in bone marrows participated in the production of endogenous formaldehyde in bone cancer pain rats. METHODOLOGY/PRINCIPAL FINDINGS: Concentration of the endogenous formaldehyde was measured by high performance liquid chromatography (HPLC). Endogenous formaldehyde dramatically increased in cultured MRMT-1 breast cancer cells in vitro, in bone marrows and sera of bone cancer pain rats, in tumor tissues and sera of MRMT-1 subcutaneous vaccination model rats in vivo. Formaldehyde at a concentration as low as the above measured (3 mM) induced pain behaviors in normal rats. The expression of LSD1 which mainly located in nuclei of cancer cells significantly increased in bone marrows of bone cancer pain rats from 14 d to 21 d after inoculation. Furthermore, inhibition of LSD1 decreased the production of formaldehyde in MRMT-1 cells in vitro. Intraperitoneal injection of LSD1 inhibitor pargyline from 3 d to 14 d after inoculation of MRMT-1 cancer cells reduced bone cancer pain behaviors. CONCLUSION: Our data in the present study, combing our previous report, suggested that in the endogenous formaldehyde-induced pain in bone cancer pain rats, LSD1 in metastasized cancer cells contributed to the production of the endogenous formaldehyde.

Contribution of the spinal cord BDNF to the development of neuropathic pain by activation of the NR2B-containing NMDA receptors in rats with spinal nerve ligation.

The NMDA receptor and the brain-derived neurotrophic factor (BDNF) are involved in central sensitization and synaptic plasticity in the spinal cord. To determine whether the spinal cord BDNF contributes to the development and maintenance of neuropathic pain by activation of the dorsal horn NR2B-containing NMDA (NMDA-2B) receptors, this study was designed to investigate if alterations in BDNF and its TrkB receptor in the spinal dorsal horn would parallel the timeline of the development of neuropathic pain in lumbar 5 (L5) spinal nerve ligated (SNL) rats. The enzyme-linked immunosorbent assay (ELISA) showed that the BDNF concentration significantly increased during 24 h post-surgery, and the maximal enhancement lasted for 48 h. It declined as time progressed and returned to the level of pre-operation at 28 days after SNL. In parallel with the alteration of BDNF concentration in the spinal dorsal horn, the 50% paw withdrawal threshold (PWT) of the ipsilateral hind paw in SNL rats also showed a significant decrease during 24-48 h after SNL as compared with those in sham-operated rats. The correlation analysis revealed that the BDNF concentration had a negative correlation with 50% PWT in early stage (0-48 h) (r=-0.974, p=0.001), but not late stage (3-28 days) (r=0.3395, p=0.6605), after SNL. Similarly, the immunohistochemical staining revealed that a significant up-regulation of BDNF expression in the spinal dorsal horn appeared as early as 12 h post-operation in SNL rats, peaked at 24-48 h, declined at 3 days and disappeared at 14 days after SNL. In contrast, an increase in NMDA-2B receptors expression in the spinal dorsal horn was delayed to 48 h after SNL. The increase reached peak at 3 days, lasted for 14 days, and returned to the control level of pre-operation at 28 days after SNL. The maximal enhancement of BDNF expression occurred in early stage (24-48 h) after nerve injury, while the peak of NMDA-2B receptors expression appeared in late stage (3-14 days) post-nerve ligation. As compared with the dynamic changes of 50% PWT in the timeline after nerve injury, the maximal enhancement of BDNF expression closely paralleled the maximal decline in the slope of 50% PWT, while the peak of NMDA-2B receptors expression corresponded with the plateau of the decreased 50% PWT. Therefore, the increased BDNF in the spinal dorsal horn was likely to be associated with the initiation of neuropathic pain in early stage (0-48 h), while the activation of NMDA-2B receptors was involved in the maintenance of persistent pain states in late stage (2-14 days) after nerve injury. Moreover, the present study also demonstrated that the BDNF/TrkB-mediated signaling pathway within the spinal cord might be involved in the induction of neuropathic pain in early stage after nerve injury, and the selective NMDA-2B receptors antagonist (Ro 25-6981) almost completely blocked the BDNF-induced mechanical allodynia in all of the tested rats. These data suggested that the BDNF/TrkB-mediated signaling pathway in the spinal cord was involved in the development of nerve injury-induced neuropathic pain through the activation of dorsal horn NMDA-2B receptors.