CFA-treated Mice Induce Hyperalgesia in Healthy mice via an olfactory mechanism

Background Social interactions with subjects experiencing pain can increase nociceptive sensitivity in observers, even without direct physical contact. In previous experiments, extended indirect exposure to soiled bedding from mice with alcohol withdrawal-related hyperalgesia enhanced nociception in their conspecifics. This finding suggested that olfactory cues could be sufficient for nociceptive hypersensitivity in otherwise untreated animals (also known as “bystanders”). Aim The current study addressed this possibility using an inflammation-based hyperalgesia model and long- and short-term exposure paradigms in C57BL/6J mice. Materials & Method Adult male and female mice received intraplantar injection of complete Freund\u27s adjuvant (CFA) and were used as stimulus animals to otherwise naïve same-sex bystander mice (BS). Another group of untreated mice (OLF) was simultaneously exposed to the bedding of the stimulus mice. Results In the long-term, 15-day exposure paradigm, the presence of CFA mice or their bedding resulted in reduced von Frey threshold but not Hargreaves paw withdrawal latency in BS or OLF mice. In the short-term paradigm, 1-hr interaction with CFA conspecifics or 1-hr exposure to their bedding induced mechanical hypersensitivity in BS and OLF mice lasting for 3 hrs. Chemical ablation of the main olfactory epithelium prevented bedding-induced and stimulus mice-induced mechanical hypersensitivity. Gas chromatography-mass spectrometry (GC-MS) analysis of the volatile compounds in the bedding of experimental mice revealed that CFA-treated mice released an increased number of compounds indicative of disease states

Effects of social housing on alcohol intake in mice depend on the non-social environment

BackgroundExcessive alcohol consumption leads to serious health problems. Mechanisms regulating the consumption of alcohol are insufficiently understood. Previous preclinical studies suggested that non-social environmental and social environmental complexities can regulate alcohol consumption in opposite directions. However, previous studies did not include all conditions and/or did not include female rodents. Therefore, in this study, we examined the effects of social versus single housing in standard versus non-standard housing conditions in male and female mice.MethodsAdult C57BL/6 J mice were housed in either standard shoebox cages or in automated Herdsman 2 (HM2) cages and exposed to a two-bottle choice procedure with 3% or 6% ethanol versus water for 5 days. The HM2 cages use radiotracking devices to measure the fluid consumption of individual mice in an undisturbed and automated manner. In both housing conditions, mice were housed either at one or at four per cage.ResultsIn standard cages, group housing of animals decreased alcohol consumption and water consumption. In HM2 cages, group housing significantly increased ethanol preference and decreased water intake. There were no significant differences in these effects between male and female animals. These observations were similar for 3 and 6% ethanol solutions but were more pronounced for the latter. The effects of social environment on ethanol preference in HM2 cages were accompanied by an increase in the number of approaches to the ethanol solution and a decrease in the number of approaches to water. The differences in ethanol intake could not be explained by differences in locomotor or exploratory activity as socially housed mice showed fewer non-consummatory visits to the ethanol solutions than single-housed animals. In addition, we observed that significant changes in behaviors measuring the approach to the fluid were not always accompanied by significant changes in fluid consumption, and vice versa, suggesting that it is important to assess both measures of motivation to consume alcohol.ConclusionOur results indicate that the direction of the effects of social environment on alcohol intake in mice depends on the non-social housing environment. Understanding mechanisms by which social and non-social housing conditions modulate alcohol intake could suggest approaches to counteract environmental factors enhancing hazardous alcohol consumption

A mechanistic study of hyperbaric oxygen-induced antinociception in a rat model of neuropathic pain

Hyperbaric oxygen (HBO2) has been shown to produce pain relief in patients with chronic pain and long-lasting antinociception in experimental animals. However, the Food and Drug Administration has not approved HBO2 as a treatment for pain, because clinical evidence of its efficacy is lacking and its mechanism of action is still not well understood. Thus, the aim of this project was to further explore the mechanism of HBO2-induced antinociception in a rat model of neuropathic pain.We hypothesized that HBO2 produced a long-lasting antinociception via a nitric oxide (NO)-mediated supraspinal pathway. To test the hypothesis, male Sprague-Dawley rats were used and repeatedly injected with paclitaxel to develop neuropathic pain. To examine the effect of HBO2 on the neuropathic pain, subgroups of rats received a single 60-min HBO2 treatment or four daily 60-min treatments after paclitaxel injections. To study the role of supraspinal NO in HBO2-induced antinociception, an nNOS inhibitor S-methyl-L-thiocitrulline (SMTC) was delivered into the cerebroventricular system during HBO2 treatment. To study the involvement of the rostral ventromedial medulla (RVM) in HBO2 antinociceptive mechanism, the RVM of the rat was inactivated with microinjections of lidocaine prior to HBO2 treatment. Both mechanical and cold allodynic responses of the rat were tested every other day for a month to assess the development of neuropathic pain and the effects of different treatments. In addition, the gene and the protein expression of nNOS in the periaqueductal gray (PAG) and the RVM were examined to examine the effect of HBO2 on NO production in these two structures.The results of the present project demonstrate that HBO2 significantly reduced paclitaxel-induced mechanical and cold allodynia for at least three weeks. Intracerebroventricular infusion of 1 mM SMTC suppressed the antinociceptive effect against mechanical but not cold allodynia, but inactivation of the RVM with 2% w/v lidocaine suppressed the antinociceptive effect against cold but not mechanical allodynia. In addition, HBO2 treatment increased the protein expression of nNOS in the PAG and the number of nNOS-positive neurons in the RVM. Collectively, these results suggest that the HBO2-induced antinociceptive mechanism may involve NO-mediated neuronal activity in the PAG-RVM pain-regulating system

Involvement of spinal cord opioid mechanisms in the acute antinociceptive effect of hyperbaric oxygen in mice

Earlier research has demonstrated that treatment with hyperbaric oxygen (HBO2) can elicit an antinociceptive response in models of acute pain. We have demonstrated that this antinociceptive effect is centrally-mediated and is dependent on opioid receptors. The purpose of the present study was to examine the role of endogenous opioid peptides and opioid receptors specifically in the spinal cord in the acute antinociceptive effect of HBO2 in mice. Male NIH Swiss mice were exposed to HBO2 (100% oxygen at 3.5atm absolute) for 11min and their antinociceptive responsiveness was determined using the glacial acetic acid-induced abdominal constriction test. HBO2-induced antinociception was sensitive to antagonism by intrathecal (i.t.) pretreatment with the κ- and μ-selective opioid antagonists norbinaltorphimine and β-funaltrexamine, respectively, but not the δ-selective antagonist naltrindole. The antinociceptive effect of HBO2 was also significantly attenuated by i.t. pretreatment with a rabbit antiserum against rat dynorphin1–13 but not antisera against β-endorphin or methionine–enkephalin. Based on these experimental findings, the acute antinociceptive effect of HBO2 appears to involve neuronal release of dynorphin and activation of κ- and μ-opioid receptors in the spinal cord. •HBO2 produces acute antinociception in the mouse abdominal constriction test.•HBO2 antinociception is antagonized by norbinaltorphimine and β-funaltrexamine.•HBO2 antinociception is antagonized by rabbit antiserum against rat dynorphin.•HBO2 antinociception involves activation of opioid mechanisms in the spinal cord

Involvement of endocannabinoid mechanisms in the antinociceptive effect of N2O in mice

Role of endocannabinoid mechanisms in pain relief induced by nitrous oxide (laughing gas)

Structural transitions upon guide RNA binding and their importance in Cas12g-mediated RNA cleavage.

Cas12g is an endonuclease belonging to the type V RNA-guided CRISPR-Cas family. It is known for its ability to cleave RNA substrates using a conserved endonuclease active site located in the RuvC domain. In this study, we determined the crystal structure of apo-Cas12g, the cryo-EM structure of the Cas12g-sgRNA binary complex and investigated conformational changes that occur during the transition from the apo state to the Cas12g-sgRNA binary complex. The conserved zinc finger motifs in Cas12g undergo an ordered-to-disordered transition from the apo to the sgRNA-bound state and their mutations negatively impact on target RNA cleavage. Moreover, we identified a lid motif in the RuvC domain that undergoes transformation from a helix to loop to regulate the access to the RuvC active site and subsequent cleavage of the RNA substrate. Overall, our study provides valuable insights into the mechanisms by which Cas12g recognizes sgRNA and the conformational changes it undergoes from sgRNA binding to the activation of the RNase active site, thereby laying a foundation for the potential repurposing of Cas12g as a tool for RNA-editing

Rapeseed Variety Recognition Based on Hyperspectral Feature Fusion

As an important oil crop, rapeseed contributes to the food security of the world. In recent years, agronomists have cultivated many new varieties, which has increased human nutritional needs. Variety recognition is of great importance for yield improvement and quality breeding. In view of the low efficiency and damage of traditional methods, in this paper, we develop a noninvasive model for the recognition of rapeseed varieties based on hyperspectral feature fusion. Three types of hyperspectral image features, namely, the multifractal feature, color characteristics, and trilateral parameters, are fused together to identify 11 rapeseed species. An optimal feature is selected using a simple rule, and then the three kinds of features are fused. The support vector machine kernel method is employed as a classifier. The average recognition rate reaches 96.35% and 93.71% for distinguishing two species and 11 species, respectively. The abundance test model demonstrates that our model possesses robustness. The high recognition rate is almost independent of the number of modeling samples and classifiers. This result can provide some practical experience and method guidance for the rapid recognition of rapeseed varieties

Schematic of sgRNA recognition by Cas12g.

Domains and residues are colored according to Fig 1(A). (TIF)</p

Crystal structure of apo-Cas12g.

(A) Domain organization of Cas12g. The amino acid segment marked by the solid gray line represents the unresolved region. (B) Overall structure of apo Cas12g shown in one view (left) and rotated through 180° (right). (C) Surface representations of apo Cas12g in the same views as in (B).</p