Improvement of l-citrulline production in Corynebacterium glutamicum by ornithine acetyltransferase

In this study, Corynebacterium glutamicum ATCC 13032 was engineered to produce l-citrulline through a metabolic engineering strategy. To prevent the flux away from l-citrulline and to increase the expression levels of genes involved in the citrulline biosynthesis pathway, the argininosuccinate synthase gene (argG) and the repressor gene (argR) were inactivated. The engineered C. glutamicum ATCC 13032 ∆argG ∆argR (CIT 2) produced higher amounts of l-citrulline (5.43 g/L) compared to the wildtype strain (0.15 g/L). To determine new strategies for further enhancement of l-citrulline production, the effect of l-citrulline on ornithine acetyltransferase (EC 2.3.1.35; OATase; ArgJ) was first investigated. Citrulline was determined to inhibit Ornithine acetyltransferase; for 50 % inhibition, citrulline concentration was 30 mM. The argJ gene from C. glutamicum ATCC 13032 was cloned, and the recombinant shuttle plasmid pXMJ19-argJ was constructed and expressed in C. glutamicum ATCC 13032 ∆argG ∆argR (CIT 2). Overexpression of the argJ gene exhibited increased OAT activity and resulted in a positive effect on citrulline production (8.51 g/L). These results indicate that OAT plays a vital role during l-citrulline production in C. glutamicum.

Concurrence of de-alloying and re-alloying in a ternary Al67Cu18Sn15 alloy and the fabrication of 3D nanoporous Cu–Sn composite structures

The creation of nanoporous Cu₃Sn–Cu–Cu₆Sn₅ composite structures in the form of self-supporting foils through the concurrence of de-alloying and re-alloying.

Serum neuron-specific enolase is elevated as a novel indicator of diabetic retinopathy including macular oedema

AIM

Neuron-specific enolase as a potential biomarker of diabetic retinopathy, a neurovascular disease, had not been fully explored. We aimed to investigate the relationship between NSE and diabetic retinopathy.

METHODS

Participants included Type 1 and Type 2 diabetes patients and healthy controls (n = 392). In this cross-sectional study, diabetic retinopathy status was assessed by fundus photographs. Serum neuron-specific enolase was measured using an electrochemiluminescence immunoassay. Co-variables for diabetic retinopathy and neuron-specific enolase were obtained from fasting blood samples and interviewer questionnaires.

RESULTS

Neuron-specific enolase was slightly elevated in diabetic patients, in contrast to healthy participants, and obviously increased in diabetic patients with retinopathy compared with those without [8.3 (2.0) vs. 7.6 (1.5), P = 0.037 and 8.3 (2.0) vs. 9.5 (2.7), P = 0.004, respectively]. In addition, neuron-specific enolase levels increased with and were closely correlated to the stages of retinopathy without macular oedema [r = 0.60 (0.50-0.71), P = 0.002] and stages of macular oedema with comparable retinopathy [r = 0.58 (0.46-0.69), P = 0.006]. The association of neuron-specific enolase with diabetic retinopathy was independent [odds ration (OR): 1.31 (1.12-1.65), P = 0.017], after the diabetic state and other potential confounders affecting NSE levels were considered (e.g., HbA1c , duration, age, gender, renal status and medicines). The optimal cut-off point for serum neuron-specific enolase levels for differentiating between participants with diabetic retinopathy including macular oedema and those without was 9.3 μg/l, with a sensitivity of 67.5% and a specificity of 69.8%.

CONCLUSIONS

Serum neuron-specific enolase is elevated in and indicative of diabetic retinopathy. Neuron-specific enolase may be a potential biomarker of diabetic retinopathy. Future prospective studies are warranted to clarify the relationship.

Expression of CDCA8 correlates closely with FOXM1 in breast cancer: public microarray data analysis and immunohistochemical study

Forkhead Box M1 (FOXM1) is an oncogenic transcription factor implicated in breast cancer progression and metastasis. However, the clinical significance of FOXM1 and its associated signaling genes in human breast cancer still needed to be clarified. In this study, we first analyzed the co-expression gene pattern of FOXM1 in three breast cancer gene expression microarray datasets from the Oncomine database. Cell division cycle associated 8 (CDCA8) gene was identified to correlate closely with FOXM1. In silico analysis further indicated that CDCA8 overexpressed in breast cancer tissues compared with the normal controls is significantly associated with the triple-negative phenotype. Experimentally, we performed a immunohistochemical study to detect the expression of CDCA8 in 112 breast cancer samples, and evaluated its clinicopathological and prognostic significance. We found that CDCA8 was frequently over-expressed in breast cancer tissues, and increased expression of CDCA8 was positively associated with FOXM1 expression, triple-negative phenotype and shorter overall survival. Moreover, we also found that combination of CDCA8 and FOXM1 showed a higher hazard ratio than the individual markers. Our results suggest that FOXM1-CDCA8 signature might be involved in breast cancer progression, and serves as a potential prognostic factor and a promising therapeutical target.

Sevoflurane promotes the expansion of glioma stem cells through activation of hypoxia-inducible factors in vitro

BACKGROUND

Growing evidences indicate that inhalational anaesthetics can enhance the growth and malignant potential of tumour cells and may affect tumour recurrence after surgery. Tumour stem cells play a vital role in tumour recurrence. This study investigates the effect of sevoflurane on glioma stem cells (GSCs) in vitro and the underlying molecular mechanisms in this process.

METHODS

Cultured GSCs were exposed to clinically relevant concentrations and durations of sevoflurane exposure. Cell proliferation and self-renewal capacity were determined. Expression of the stem cell marker CD133, vascular endothelial growth factor (VEGF), hypoxia-inducible factors (HIFs), and phosphorylated Akt, which is a protein kinase invoved in multiple cellular processes, were measured using western blotting. Small interfering RNAs and an Akt inhibitor were used to investigate specific pathways.

RESULTS

Compared with controls, cells exposed to 2% sevoflurane for 6 h induced a larger number of proliferated cells (31.2±7.6% vs 19.0±5.8%; P<0.01). Levels of CD133, VEGF, HIF-1α, HIF-2α, and p-Akt were up-regulated by sevoflurane in a time- and concentration-dependent manner. Small interfering RNA against HIFs decreased the percentage of proliferating GSCs after sevoflurane exposure and pre-treatment of cells with an Akt inhibitor abrogated the expression of HIFs induced by sevoflurane.

CONCLUSIONS

Sevoflurane can promote the expansion of human GSCs through HIFs in vitro. Inhaled anaesthetics may enhance tumour growth through tumour stem cells.

Increased blood-oxygen binding affinity in Tibetan and Han Chinese residents at 4200 m

High-altitude natives are challenged by hypoxia, and a potential compensatory mechanism could be reduced blood oxygen-binding affinity (P50), as seen in several high-altitude mammalian species. In 21 Qinghai Tibetan and nine Han Chinese men, all resident at 4200 m, standard P50 was calculated from measurements of arterial PO2 and forehead oximeter oxygen saturation, which was validated in a separate examination of 13 healthy subjects residing at sea level. In both Tibetans and Han Chinese, standard P50 was 24.5 ± 1.4 and 24.5 ± 2.0 mmHg, respectively, and was lower than in the sea-level subjects (26.2 ± 0.6 mmHg, P < 0.01). There was no relationship between P50 and haemoglobin concentration (the latter ranging from 15.2 to 22.9 g dl(-1) in Tibetans). During peak exercise, P50 was not associated with alveolar-arterial PO2 difference or peak O2 uptake per kilogram. There appears to be no apparent benefit of a lower P50 in this adult high-altitude Tibetan population.

Reversal effect of vitamin D on different multidrug-resistant cells

We investigated the reversal effect of vitamin D on the multidrug-resistant leukemic Jurkat/ADR and K562/ADR cell lines and conducted a preliminary investigation of its reversal mechanism. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method was used to detect the reversal effect of vitamin D on multidrug-resistant cells. Real-time polymerase chain reaction was used to determine the effect of vitamin D on intracellular expression of mRNA of the multidrug-resistant gene (MDRI) and the multidrug-resistance-related gene (MRP1). A protein quantitative analysis method was used to determine the effect of vitamin D on intracellular glutathione content. After treatment of Jurkat/ADR and K562/ADR cells with vitamin D, multidrug resistance was reversed in a dose-dependent manner, which may have reduced mRNA expression of the MDR1 and MRP1 genes, the P-glycoprotein content on the cell surface, and the intracellular glutathione level. Different concentrations of vitamin D showed varying reversal effects on different multidrug-resistant cells. The resistance mechanism may be related to the inhibition of the expression of MDR1 and MRP1 genes.

Gas chromatograph-surface acoustic wave for quick real-time assessment of blood/exhaled gas ratio of propofol in humans

BACKGROUND

Although pilot studies have reported that exhaled propofol concentrations can reflect intraoperative plasma propofol concentrations in an individual, the blood/exhaled partial pressure ratio RBE varies between patients, and the relevant factors have not yet been clearly addressed. No efficient method has been reported for the quick evaluation of RBE and its association with inter-individual variables.

METHODS

We proposed a novel method that uses a surface acoustic wave (SAW) sensor combined with a fast gas chromatograph (GC) to simultaneously detect propofol concentrations in blood and exhaled gas in 28 patients who were receiving propofol i.v. A two-compartment pharmacokinetic (PK) model was established to simulate propofol concentrations in exhaled gas and blood after a bolus injection. Simulated propofol concentrations for exhaled gas and blood were used in a linear regression model to evaluate RBE.

RESULTS

The fast GC-SAW system showed reliability and efficiency for simultaneous quantitative determination of propofol in blood (correlation coefficient R(2)=0.994, P<0.01) and exhaled gas (R(2)=0.991, P<0.01). The evaluation of RBE takes <50 min for a patient. The distribution of RBE in 28 patients showed inter-individual differences in RBE (median 1.27; inter-quartile range 1.07-1.59).

CONCLUSIONS

Fast GC-SAW, which analyses samples in seconds, can perform both rapid monitoring of exhaled propofol concentrations and fast analysis of blood propofol concentrations. The proposed method allows early determination of the coefficient RBE in individuals. Further studies are required to quantify the distribution of RBE in a larger cohort and assess the effect of other potential factors.

CLINICAL TRIAL REGISTRATION

ChiCTR-ONC-13003291.

The economic burden of fracture patients with osteoporosis in western China

To study the cost of osteoporotic fracture in China, we performed a prospective study and compared the costs of the disease in referral patients with fractures in three of the most common sites. Our results indicated that the economic burden of osteoporotic fracture to both Chinese patients and the nation is heavy.

INTRODUCTION

This paper aims to study the cost of osteoporotic fracture in China and thus to provide essential information about the burden of this disease to individuals and society.

METHODS

This prospective observational data collection study assessed the cost related to hip, vertebral, and wrist fracture 1 year after the fracture based on a patient sample consisting of 938 men and women. Information was collected using patient records, registry sources, and patient interviews. Both direct medical, direct non-medical, and indirect non-medical costs were considered.

RESULTS

The annual total costs were highest in hip fracture patients (renminbi, RMB 27,283 or USD 4,330, with confidence interval (RMB 25715, 28851)), followed by patients with vertebral fracture (RMB 21,474 or USD 3,409, with confidence interval (RMB 20082, 22866)) and wrist fracture (RMB 8,828 or USD 1,401, with confidence interval (RMB 7829, 9827)). The direct medical care costs averaged approximately RMB 17,007 per year per patient, of which inpatient costs, drugs, and investigations accounted for the majority of the costs. Nonmedical direct costs were much less compared to direct healthcare costs and averaged approximately RMB 1,846.

CONCLUSION

These results indicate that the economic burden of osteoporotic fracture to both Chinese patients and China was heavy, and the proportion of the costs in China demonstrated many similar features and some significant differences compared to other countries.

Delivery of an miR155 inhibitor by anti-CD20 single-chain antibody into B cells reduces the acetylcholine receptor-specific autoantibodies and ameliorates experimental autoimmune myasthenia gravis

MicroRNA-155 (miR155) is required for antibody production after vaccination with attenuated Salmonella. miR155-deficient B cells generated reduced germinal centre responses and failed to produce high-affinity immunoglobulin (Ig)G1 antibodies. In this study, we observed up-regulation of miR155 in the peripheral blood mononuclear cells (PBMCs) of patients with myasthenia gravis (MG), and miR155 was also up-regulated in torpedo acetylcholine receptor (T-AChR)-stimulated B cells. We used an inhibitor of miR155 conjugated to anti-CD20 single-chain antibody to treat both the cultured B cells and the experimental autoimmune MG (EAMG) mice. Our results demonstrated that silencing of miR155 by its inhibitor impaired the B cell-activating factor (BAFF)-R-related signalling pathway and reduced the translocation of nuclear factor (NF)-κB into the nucleus. Additionally, AChR-specific autoantibodies were reduced, which may be related to the altered amounts of marginal zone B cells and memory B cells in the spleens of EAMG mice. Our study suggests that miR155 may be a promising target for the clinical therapy of MG.

Association of the CYP1A1 MspI and TNFα-308 polymorphisms with chronic obstructive pulmonary disease in Inner Mongolia

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by persistent airflow limitation. Smoking, occupational exposures, air pollution, and genetics are all risk factors. In the present study, we detected the cytochrome P4501A1 gene (CYP1A1) MspI polymorphism and the tumor necrosis factor alpha (TNFα)-308 single nucleotide polymorphism in COPD patients, and investigated their associations with smoking and COPD susceptibility in Inner Mongolia. A total of 101 COPD patients and 80 controls were enrolled in the study. The polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). CYP1A1 MspI allele frequencies were significantly different between COPD patients and controls (P=0.033). COPD susceptibility was higher in subjects with the m2 allele compared to subjects with the m1 allele [odds ratio (OR)=2.531, 95% confidence interval (CI)=1.297-4.940, P=0.006]. Significant differences were observed in the TNFα-308 genotype and allele distributions between COPD patients and controls (P=0.006 and P=0.003, respectively). Compared to subjects with the GG genotype, subjects with GA+AA genotypes had higher COPD risk (OR=3.639, 95%CI=1.576-8.403, P=0.002). The TNFα-308 polymorphism differed between smoking and non-smoking COPD patients and controls (P=0.047 for genotype and P=0.030 for allele). In conclusion, the CYP1A1 MspI and TNFα-308 polymorphisms were associated with COPD susceptibility. Furthermore, of the two polymorphisms, only TNFα-308 may exert an interaction with smoking.

Spinal ephrinB/EphB signalling contributed to remifentanil-induced hyperalgesia via NMDA receptor

Background

One of the major unresolved issues in treating pain is the paradoxical hyperalgesia produced by opiates, and accumulating evidence implicate that EphBs receptors and ephrinBs ligands are involved in mediation of spinal nociceptive information and central sensitization, but the manner in which ephrinB/EphB signalling acts on spinal nociceptive information networks to produce hyperalgesia remains enigmatic. The objective of this research was to investigate the role of ephrinB/EphB signalling in remifentanil-induced hyperalgesia (RIH) and its downstream effector.

Methods

We characterized the remifentanil-induced pain behaviours by evaluating thermal hyperalgesia and mechanical allodynia in a rat hind paw incisional model. Protein expression of EphB1 receptor and ephrinB1 ligand in spinal dorsal horn cord was determined by Western blotting, and Fos was determined by immunohistochemistry assay, respectively. To figure out the manner in which ephrinB/EphB signalling acts with N-methyl-d-aspartic acid (NMDA) receptor, we used MK-801, an antagonist of NMDA receptor, trying to suppressed the hyperalgesia induced by ephrinB1-Fc, an agonist of ephrinB/EphB.

Results

Continuing infusion of remifentanil produced a thermal hyperalgesia and mechanical allodynia, which was accompanied with increased protein expression of spinal-level EphB1 receptor, ephrinB1 ligand and Fos; what appeared above was suppressed by pretreatment with EphB1-Fc, an antagonist of ephrinB/EphB or MK-801, and increased pain behaviours induced by intrathecal injection of ephrinB1-Fc, an agonist of ephrinB/EphB, were suppressed by MK-801.

Conclusions

Our findings indicated that ephrinB/EphB signalling is involved in RIH. EphrinB/EphB signalling might be the upstream of NMDA receptor.

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Impacts of trace carbon on the microstructure of as-sintered biomedical Ti-15Mo alloy and reassessment of the maximum carbon limit

The formation of grain boundary (GB) brittle carbides with a complex three-dimensional (3-D) morphology can be detrimental to both the fatigue properties and corrosion resistance of a biomedical titanium alloy. A detailed microscopic study has been performed on an as-sintered biomedical Ti-15Mo (in wt.%) alloy containing 0.032 wt.% C. A noticeable presence of a carbon-enriched phase has been observed along the GB, although the carbon content is well below the maximum carbon limit of 0.1 wt.% specified by ASTM Standard F2066. Transmission electron microscopy (TEM) identified that the carbon-enriched phase is face-centred cubic Ti2C. 3-D tomography reconstruction revealed that the Ti2C structure has morphology similar to primary α-Ti. Nanoindentation confirmed the high hardness and high Young's modulus of the GB Ti2C phase. To avoid GB carbide formation in Ti-15Mo, the carbon content should be limited to 0.006 wt.% by Thermo-Calc predictions. Similar analyses and characterization of the carbide formation in biomedical unalloyed Ti, Ti-6Al-4V and Ti-16Nb have also been performed.

MicroRNA-193a-3p and -5p suppress the metastasis of human non-small-cell lung cancer by downregulating the ERBB4/PIK3R3/mTOR/S6K2 signaling pathway

The metastatic cascade is a complex and multistep process with many potential barriers. Recent evidence has shown that microRNAs (miRNAs) are involved in carcinogenesis and tumor progression in non-small-cell lung cancer (NSCLC). In this study, by comparing the miRNA expression profiles of SPC-A-1sci (high metastatic) and SPC-A-1 (weakly metastatic) cells, we demonstrated that the downregulation and function of miR-193a-3p and miR-193a-5p in NSCLC metastasis and the expression of these miRNAs was suppressed in NSCLC compared with corresponding non-tumorous tissues. Decreased miR-193a-3p/5p expression was significantly associated with tumor node metastasis (TNM) and lymph node metastasis. Furthermore, functional assays showed that the overexpression of miR-193a-3p/5p inhibited NSCLC cell migration, invasion and epithelial-mesenchymal transition (EMT) in vitro and lung metastasis formation in vivo. In addition, we discovered that ERBB4 and S6K2 were the direct targets of miR-193a-3p and that PIK3R3 and mTOR were the direct targets of miR-193a-5p in NSCLC. We also observed that miR-193a-3p/5p could inactivate the AKT/mTOR signaling pathway. Thus, miR-193a-3p/5p functions as a tumor suppressor and has an important role in NSCLC metastasis through ERBB signaling pathway.

Curcumin promotes the apoptosis of human endometrial carcinoma cells by downregulating the expression of androgen receptor through Wnt signal pathway

OBJECTIVE

The current study aimed to explore the effect ofcurcumin on androgen receptor (AR) expression in endometrial carcinoma cells, as well as the underlying mechanisms.

MATERIALS AND METHODS

Endometrial carcinoma cells were treated with curcumin (10, 50, and 100 micromol/l) for 12, 24, and 48 hours. Their growth curves were drawn using MTT assays and their apoptotic rates were determined using flow cytometry. The mRNA and protein expression of AR was detected using PCR and that of the Wnt signal related nucleopro- tein beta-cantenin was observed using western blot analysis. The influence of beta-cantenin on the action of curcumin was observed.

RESULTS

Curcumin downregulated the proliferation and apoptosis of human endometrial carcinoma cells in concentration and time-dependent manners. It downregulated the expression of AR and beta-cantenin in the cells. rWnt3a partially cancelled the effects of curcumin on the proliferation and apoptosis of human endometrial carcinoma cells as well as the AR expression-downregulating effect of curcumin.

CONCLUSION

Curcumin inhibits the proliferation and apoptosis of human endometrial carcinoma cells by downregulating their AR expression through the Wnt signal pathway.

Measuring uncertainty in dose delivered to the cochlea due to setup error during external beam treatment of patients with cancer of the head and neck

PURPOSE

To use Cone Beam CT scans obtained just prior to treatments of head and neck cancer patients to measure the setup error and cumulative dose uncertainty of the cochlea.

METHODS

Data from 10 head and neck patients with 10 planning CTs and 52 Cone Beam CTs taken at time of treatment were used in this study. Patients were treated with conventional fractionation using an IMRT dose painting technique, most with 33 fractions. Weekly radiographic imaging was used to correct the patient setup. The authors used rigid registration of the planning CT and Cone Beam CT scans to find the translational and rotational setup errors, and the spatial setup errors of the cochlea. The planning CT was rotated and translated such that the cochlea positions match those seen in the cone beam scans, cochlea doses were recalculated and fractional doses accumulated. Uncertainties in the positions and cumulative doses of the cochlea were calculated with and without setup adjustments from radiographic imaging.

RESULTS

The mean setup error of the cochlea was 0.04 ± 0.33 or 0.06 ± 0.43 cm for RL, 0.09 ± 0.27 or 0.07 ± 0.48 cm for AP, and 0.00 ± 0.21 or -0.24 ± 0.45 cm for SI with and without radiographic imaging, respectively. Setup with radiographic imaging reduced the standard deviation of the setup error by roughly 1-2 mm. The uncertainty of the cochlea dose depends on the treatment plan and the relative positions of the cochlea and target volumes. Combining results for the left and right cochlea, the authors found the accumulated uncertainty of the cochlea dose per fraction was 4.82 (0.39-16.8) cGy, or 10.1 (0.8-32.4) cGy, with and without radiographic imaging, respectively; the percentage uncertainties relative to the planned doses were 4.32% (0.28%-9.06%) and 10.2% (0.7%-63.6%), respectively.

CONCLUSIONS

Patient setup error introduces uncertainty in the position of the cochlea during radiation treatment. With the assistance of radiographic imaging during setup, the standard deviation of setup error reduced by 31%, 42%, and 54% in RL, AP, and SI direction, respectively, and consequently, the uncertainty of the mean dose to cochlea reduced more than 50%. The authors estimate that the effects of these uncertainties on the probability of hearing loss for an individual patient could be as large as 10%.

Mineral trioxide aggregate enhances the odonto/osteogenic capacity of stem cells from inflammatory dental pulps via NF-κB pathway

OBJECTIVE

This study was designed to investigate the effects of mineral trioxide aggregate (MTA) on the osteo/odontogenic differentiation of inflammatory dental pulp stem cells (iDPSCs).

MATERIALS AND METHODS

inflammatory DPSCs were isolated from the inflammatory pulps of rat incisors and cocultured with MTA-conditioned medium. MTT assay and flow cytometry were performed to evaluate the proliferation of iDPSCs. Alkaline phosphatase (ALP) activity, alizarin red staining, real-time RT-PCR, and Western blot assay were used to investigate the differentiation capacity as well as the involvement of NF-κB pathway in iDPSCs.

RESULTS

Mineral trioxide aggregate-treated iDPSCs demonstrated the higher ALP activity and formed more mineralized nodules than the untreated group. The odonto/osteoblastic markers (Alp, Runx2/RUNX2, Osx/OSX, Ocn/OCN, and Dspp/DSP, respectively) in MTA-treated iDPSCs were significantly upregulated as compared with untreated iDPSCs. Mechanistically, cytoplastic phos-P65 and nuclear P65 in MTA-treated iDPSCs were significantly increased in a time-dependent manner. Moreover, the inhibition of NF-κB pathway suppressed the MTA-induced odonto/osteoblastic differentiation of iDPSCs, as indicated by decreased ALP levels, weakened mineralization capacity and downregulated levels of odonto/osteoblastic genes (Osx, Ocn, and Dspp).

CONCLUSIONS

Mineral trioxide aggregate enhances the odonto/osteogenic capacity of DPSCs from inflammatory sites via activating the NF-κB pathway.

Systematic administration of B vitamins attenuates neuropathic hyperalgesia and reduces spinal neuron injury following temporary spinal cord ischaemia in rats

BACKGROUND

B vitamins have been demonstrated to be effective in treating chronic pain due to peripheral nerve injury. We investigated whether B vitamins could alleviate neuropathic pain and reduce neuron injury following temporary ischaemia in a rat model of spinal cord ischaemia-reperfusion injury (SCII).

METHODS

SCII was produced by transiently blocking the unilateral lumbar arteries in adult male Sprague-Dawley rats. Behavioural and neurochemical signs of neuropathic pain and spinal neuron injury were analysed with and without B vitamin treatment.

RESULTS

SCII caused behavioural thermal hyperalgesia and mechanical allodynia and neurochemical alterations, including increased expression of the vanilloid receptor 1 (VR1) and induction of c-Fos, as well as activation of the astrocytes and microglial cells in the spinal cord. Repetitive systemic administration of vitamin B complex (B1/B6/B12 at 33/33/0.5 mg/kg, i.p., daily, for 7-14 consecutive days) significantly reduced thermal hyperalgesia and the increased expression of VR1 and c-Fos, as well as activation of the astrocytes and microglial cells. SCII caused a dramatic decrease of the expression of the rate-limiting enzyme glutamic acid decarboxylase-65 (GAD65), which synthesizes γ-aminobutyric acid (GABA) in the axonal terminals, and β-III-tubulin, and also caused loss of Nissl bodies in the spinal cord. These alterations were largely prevented and rescued by the B vitamin treatment.

CONCLUSIONS

These findings support the idea that the B vitamins are capable of neuroprotection and antinociception during spinal cord injury due to temporary ischaemia. Rescuing the loss of inhibitory GABAergic tone may reduce spinal central sensitization and contribute to B vitamin-induced analgesia.