Contribution of capsaicin-sensitive primary afferents to mechanical hyperalgesia induced by ventral root transection in rats: the possible role of BDNF.

OBJECTIVE: A recent study showed that brain-derived neurotrophic factor (BDNF) may play a role in the development of the neuropathic pain resulting from injury to motor efferent fibres, such as that in the ventral root transection (VRT) model. Capsaicin stimulation of afferent fibres was also shown to result in the release of BDNF into the spinal cord. Here, the effects of ablation of capsaicin-sensitive primary afferents (CSPAs) by local application of capsaicin on the sciatic nerve on VRT-induced mechanical hyperalgesia were observed. METHODS: The paw withdrawal mechanical threshold (PWMT) was measured before and then 1 and 3 days and 1, 2, 3, 4 and 6 weeks after VRT. RESULTS: The results showed that local application of capsaicin significantly inhibited the decrease in the PWMT induced by VRT, suggesting the inhibitory effect of locally delivered capsaicin. Furthermore, intrathecal administration of exogenous BDNF not only produced mechanical hyperalgesia but also significantly blocked the inhibitory effect of capsaicin. CONCLUSION: Taken together, the results of this study suggest that CSPA fibres may contribute to mechanical hyperalgesia in the VRT model.

Contribution of brain-derived neurotrophic factor to mechanical hyperalgesia induced by ventral root transection in rats.

It is generally believed that the development of neuropathic pain primarily results from injuries to sensory afferent fibers. Recent studies found that injuries to the motor efferent fibers (e.g. ventral root transection) also contribute to the development of neuropathic pain. Furthermore, an increase in brain-derived neurotrophic factor (BDNF) synthesis has been found in the ventral root transection model, suggesting a possible role of BDNF in this model. To determine the role of BDNF, we observed the effects of intrathecal antibody against BDNF treatment on ventral root transection-induced mechanical hyperalgesia. Paw withdrawal thresholds to mechanical stimuli were measured before and after surgery. The results showed that ventral root transection in rats produced a significant, lasting decrease of mechanical withdrawal thresholds, presenting the development of mechanical hyperalgesia. Intrathecal antibody against BDNF treatment markedly inhibited ventral root transection-induced mechanical hyperalgesia in a dose-related manner. The findings suggest that BDNF-mediated signaling pathway within spinal cord may be involved in the development of neuropathic pain involving injuries to motor efferent fibers.

Contribution of the spinal microglia to bee venom-induced inflammatory pain in conscious rats.

It is well known that spinal glia plays a key role in the pathogenesis of pain. The present study was designed to determine the roles of spinal microglia in bee venom-induced persistent spontaneous nociception (PSN), mechanical hyperalgesia and inflammation. We determined the effects of microglia inhibitor minocycline on BV-induced PSN, mechanical hyperalgesia and inflammatory swelling. Pre-treatment with intrathecal administration of minocyline at different doses significantly inhibited BV-induced PSN and mechanical hyperalgesia, but had no effect on BV-induced inflammatory swelling. These data suggest that the activation of spinal microglia may play a key role in BV-induced nociception, but not inflammation.

Contribution of the spinal P2X7 receptors to bee venom-induced nociception and inflammation in conscious rats.

Recently, P2X7 receptor (P2X7R) has been found to contribute to the development of inflammatory pain, however, the role of spinal P2X7R is not clear. The present study was designed to determine the roles of spinal P2X7R in the bee venom (BV) model, characterized by multiple pain-related behaviors and obvious inflammatory edema. We determined the effects of P2X7R antagonist A438790 on BV-induced PSN, mechanical allodynia and inflammatory swelling. Pre-treatment with intrathecal administration of A438079 significantly inhibited BV-induced PSN and mechanical allodynia in a dose-dependent manner, but had no effect on BV-induced inflammatory swelling. These data suggest that the activation of spinal P2X7Rs may play a key role in BV-induced nociception, but not inflammation.

Nuclear and chloroplast SSR markers in Paeonia delavayi (Paeoniaceae) and cross-species amplification in P. ludlowii.

PREMISE OF THE STUDY: Microsatellite primers were developed for Paeonia delavayi and P. ludlowii (Paeoniaceae) to study their population genetics and phytogeography. METHODS AND RESULTS: Nine polymorphic nuclear microsatellite loci were isolated from an enriched library of P. delavayi and primers were designed. The number of alleles per locus ranged from two to 16; the observed and expected heterozygosities ranged from 0.014 to 0.687 and 0.042 to 0.875, respectively. Six polymorphic chloroplast microsatellite loci were identified in P. delavayi and primers were provided. The number of alleles per locus ranged from two to six and the polymorphic information content ranged from 0.08 to 0.716. Both nuclear and chloroplast primers were successfully applicable to P. ludlowii. CONCLUSIONS: The markers developed here will facilitate analyses of genetic diversity, population genetic structure, phytogeographical patterns, and conservation for P. delavayi and P. ludlowii.

Ischemia induces endoplasmic reticulum stress and cell apoptosis in human brain.

In animal models, endoplasmic reticulum (ER) stress and apoptosis take place around cerebral infarction areas during ischemia, which presumably protect tissues from necroses-induced injury as well as promote cells toward death. We examined whether these pathological changes, especially temporal occurrence, were present in patients who suffered from cerebral ischemia. The studies by immunohistochemistry show that ER chaperone glucose-regulated protein (GRP78) and caspase-9 elevate around infarction areas. The experiments by terminal deoxynucleotidy transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick-end labeling (TUNEL) illustrate that TUNEL-positive cells are higher around infarction tissues than controls. Moreover, GRP78, caspase-9 and TUNEL cells emerge one after another during ischemia. In conclusion, ER stress, apoptosis initiation and DNA fragment develop sequentially in ischemic human brain. ER stress during excessive ischemia stimulates apoptotic cell death beyond activating a defense for nerve cells being away from injury.

[Study on factors related to top 10 junk food consumption at 8 to 16 years of age, in Haidian District of Beijing].

OBJECTIVE: To study the current situation of ten types of junk food consumption (assessed by World Health Organization) among children and adolescent as well as the contributing factors in Haidian District, Beijing so as to provide evidence for developing preventive and control measures and interventions. METHODS: A questionnaire survey was conducted to investigate the consumption of ten types of junk food practices in 1019 children and adolescent aged 8-16 years in Beijing Haidian District. RESULTS: One month prior to the study, 97.50% of the children and adolescent had eaten at least one type of junk food and 15.88% of them had eaten all types of them. Rates on having eaten deep fried food, pickled food, processed meat products, biscuits, coke or alike drinks, convenience/fast food, canned food, dried or preserved fruit, cold and sweet food, barbecue food etc. appeared to be 70.43%, 60.14%, 79.72%, 64.24%, 69.63%, 78.72%, 42.16%, 51.95%, 68.13%, 60.14% respectively. The rate on eaten more than once a day of these ten types were 26.95%, 36.88%, 34.84%, 32.97%, 27.40%, 28.18%, 37.91%, 26.15%, 37.39%, 22.10% respectively. The rates for "do not like" and "dislike" these ten types junk food were 10.96%, 27.42%, 7.08%, 12.11%, 6.56%, 6.59%, 17.80%, 13.59%, 3.42%, 5.19% respectively. Most of the children and adolescent ate junk food mainly during breakfast at home. Most of the surveyed children and adolescent did not have correct idea on nutrition of junk food. They received the information of junk food mainly from sources as advertisement on TV (67.95%), mother (9.02%), newspaper or magazines (6.71%). Many factors, such as individual factors (including physiological and psychological situations), social factors, family factors and the characteristics of food contributed to the eating junk food practices of children and adolescent. CONCLUSION: Eating junk food is a popular event among children and adolescent in Beijing Haidian District. Education strategies on nutrition should be developed and launched in order to help children develop their own healthy eating behaviors.

[Determination of the cysteine residues in the surface-confined biomolecules by using electrochemical desorption and fluorescence detection].

To develop a method for the detection of surface-confined peptides containing cysteine residues or oligodeoxynucleotides (ODNs) whose 3' ends modified with thiol groups, and a thiol-specific fluorescent cross-linker, N-(9-acridinyl) maleimide (NAM) was used. The peptides studied herein include both the oxidized and reduced forms of glutathione, and a hexapeptide (FT). Peptides are first attached onto the activated 11-mercaptoundecanoic acid (MUA)-terminated alkanethiol self-assembled monolayers (SAMs) and then derivatized with NAM. The cysteine residues was determined by using electrochemical desorption and fluorescence detection. GSH concentration as low as 40 pmol x L(-1) can be measured. The fluorescence intensity in the case of FT is about 3 times as high as that for GSH, which is consistent with the molar ratio of cysteine residues in these two molecules. The analytical performance of gene analysis was also evaluated through the analyses of a complementary target and targets with varying numbers of mismatching bases. The method described here is simple, sensitive, reproducible, and does not require sophisticated analytical instrumentation and separation procedures.

[Fingerprinting of Fuzhisan by high-performance liquid chromatography with ultraviolet and evaporative light scattering detector].

OBJECTIVE: To establish a method for fingerprinting of Fuzhisan (FZS, a traditional Chinese medicinal preparation) using high-performance liquid chromatography with ultraviolet and evaporative light scattering detector (HPLC-UV/ELSD) to allow simultaneous determination of 5 major constituents in the preparation. METHODS: HPLC-UV/ELSD analysis was performed on water AlltechC18 column (5 microm, 4.6 mm x 250 mm) with a mixture of acetonitrile (A) and 0.1% acetice acid water (B) as the mobile phase. The solvent A gradient for elution was 0, 12%; 25, 20%; 30, 20%; 75, 30%; 105, 40%; 120, 80%; 130, 12%, with the flow rate of 1.0 ml/min; and the column temperature at 30 degrees . The detective wavelength was 335 nm, drift tube temperature was 80 degrees , pressure of nebulizer gas was 25 psi. The similarities between the HPLC-UV/ELSD fingerprints of the 12 extracts were calculated using similarity evaluation software. RESULTS: The fingerprint of FZS was established and the 5 major constituents were identified. The complementarity between the fingerprints of UV and ELSD was analyzed, showing good correlation between 12 batches of FZS. CONCLUSION: The method for fingerprinting can simultaneously characterize the main chemical constituents in FZS and allows stable, effective and comprehensive quality control and evaluation of FZS for a single sample.