Alkali burn induced corneal spontaneous pain and activated neuropathic pain matrix in the central nerve system in mice

Purpose: To explore whether alkali burn causes corneal neuropathic pain and activates neuropathic pain matrix in the central nerve system in mice. Methods: A corneal alkali burn mouse model (grade II) was used. Mechanical threshold in the cauterized area was tested using Von Frey hairs. Spontaneous pain behavior was investigated with conditioned place preference (CPP). Phosphor extracellular signal-regulated kinase (ERK), which is a marker for neuronal activation in chronic pain processing, was investigated in several representative areas of the neuropathic pain matrix: the two regions of the spinal trigeminal nucleus (subnucleus interpolaris/caudalis ,Vi/Vc; subnucleus caudalis/upper cervical cord , Vc/C1), insular cortex, anterior cingulated cortex (ACC), and the rostroventral medulla (RVM). Further, pharmacologically blocking pERK activation in ACC of alkali burn mice was performed in a separate study. Results: Corneal alkali burn caused long lasting damage to the corneal subbasal nerve fibers and mice exhibited spontaneous pain behavior. By testing in several representative areas of neuropathic pain matrix in the higher nerve system, phosphor extracellular signal-regulated kinase (ERK) was significantly activated in Vc/C1, but not in Vi/Vc. Also, ERK was activated in the insular cortex, ACC, and RVM. Furthermore, pharmacologically blocking ERK activation in ACC abolished alkali burn induced corneal spontaneous pain. Conclusion: Alkali burn could cause corneal spontaneous pain and activate neuropathic pain matrix in the central nerve system. Furthermore, activation of ERK in ACC is required for alkali burn induced corneal spontaneous pain

Gene transfer to human trabecular meshwork cells in vitro and ex vivo using HIV-based lentivirus

AIM:To investigate whether the enhanced green fluorescent protein (EGFP) reporter gene could be transferred into human trabecular meshwork (HTM) cells by a HIV-based lentivirus both in vitro and ex vivo. METHODS:The HIV-based lentivirus that contains an EF1-α promoter driving EGFP expression cassette was constructed following the standard molecular cloning methods. The cultured HTM cells were transduced at a range of multiplicity of infection (MOI) with HIV-based lentivirus. EGFP positive cell populations were detected by flow cytometry. Human anterior eye segments were cultured with perfusion culture system and transfected by HIV-based lentivirus with a 1×108 transducing unit (TU) virus in perfusion liquid. The intraocular pressure was recorded every 8h for 21d. The expression of EGFP in the anterior segment of the human eye was detected by fluorescence microscopy. Furthermore, the distribution of EGFP expression was confirmed by anti-EGFP immunohistochemical staining. RESULTS:The HIV-based lentivirus which contains an EF1-α promoter driving EGFP expression cassette was constructed successfully. After HTM cells were transduced with HIV-based lentivirus containing EGFP in vitro, the ratio of EGFP positive cells to the total cell number reached 92.3%, with the MOI of 15. After the lentivirus containing EGFP were used to transduce human anterior eye segments, the EGFP could be directly detected by fluorescence microscopy in vivo. Immunohistochemistry staining revealed that 88.19% EGFP-positive trabecular meshwork (TM) cells were observed in the human anterior segment. Nevertheless, the intraocular pressure in the lentivirus-transduced group kept constant when compared with control group (P>0.05). CONCLUSION:EGFP gene could be efficiently transferred into HTM cells both in vitro and ex vivo by using HIV-based lentivirus

Intraperitoneal ropivacaine and early postoperative pain and postsurgical outcomes after laparoscoipc herniorrhaphy in toddlers: a randomized clinical trial

Background Postoperative pain can cause physiological distress, postoperative complications, and extended lengths of hospitalized stay. In children, management of postoperative pain is still recognized as being inadequate. Objective The aim of this trial was to investigate the effects of intraperitoneal ropivacaine on postoperative pain, and recovery of bowel function and emetic events after laparoscopic herniorrhaphy in toddlers. Methods Seventy-six children aged from 9 months to 3 years were recruited between August 2013 and June 2014 at Tongji Hospital and randomly assigned into two groups. One group received intraperitoneal ropivacaine right before surgery and the control group received intraperitoneal saline. A standard combined general anesthesia procedure was performed under regular monitoring. Postoperative pain was assessed by the FLACC scale. Postoperative analgesic consumption, time to flatus, time to first stool, and postoperative emetic events were also recorded. Results When compared with the control group, children who received intraperitoneal ropivacaine experienced less pain 0–4 h after surgery [P < 0.001, difference in median FLACC (95% CI) for 2 h time point is 2.00 (0.87–3.13), for 4 h time point is 1.00 (0.55–1.45)]. In addition, the number of toddlers who received analgesia 0–24 h after surgery in the ropivacaine group was lower than that in the control group [P < 0.001, difference in proportions (95% CI) is 0.575 (0.3865–0.7638)]. Compared with the control group, time to flatus in ropivacaine group was also much shorter [21.1 h vs 16.7 h, P = 0.04, difference in mean (95% CI) is 4.4 (1.49–7.28)], and the time to first stool after surgery was earlier in the ropivacaine group [30.7 h vs 25.6 h, P = 0.003, difference in mean (95% CI) is 5.1 (1.78–8.45)]. Furthermore, the incidence of emetic events in the ropivacaine group was significantly lower than the control group [32.4% vs 11.1%, P = 0.03, difference in proportions (95% CI) is 0.212 (0.0246–0.4002)]. Conclusion The present results indicate that intraperitoneal ropivacaine reduces early postoperative pain and improves recovery after laparoscopic herniorrhaphy in toddlers. Therefore, IPLA is a good stratagem for postoperative pain management after laparoscopic surgery in toddlers

MHC-I promotes apoptosis of GABAergic interneurons in the spinal dorsal horn and contributes to cancer induced bone pain

Cancer induced bone pain (CIBP) remains one of the most intractable clinical problems due to poor understanding of its underlying mechanisms. Recent studies demonstrate the decline of inhibitory interneurons, especially GABAergic interneurons in the spinal cord, can evoke generation of chronic pain. It has also been reported that neuronal MHC-I expression renders neurons vulnerable to cytotoxic CD8+ T cells and finally lead to neurons apoptosis in a variety neurological disorders. However, whether MHC-I could induce the apoptosis of GABAergic interneurons in spinal cord and contribute to the development of CIBP remains unknown. In this study, we investigated roles of MHC-I and underlying mechanisms in CIBP on a rat model. Our results showed that increased MHC-I expression on GABAergic interneurons could deplete GABAergic interneurons by inducing their apoptosis in the spinal dorsal horn of tumor-bearing rats. Pretreatment of MHC-I RNAi-lentivirus could prevent the apoptosis of GABAergic interneurons and therefore alleviated mechanical allodynia induced by tumor cells intratibial injection. Additionally, we also found that CD8+ T cells were colocalized with MHC-I and GABAergic neurons and presented a significant and persistent increase in the spinal cord of tumor-bearing rats. Taken together, these findings indicated that MHC-I could evoke CIBP by promoting apoptosis of GABAergic interneurons in the dorsal horn, and this apoptosis was closely related to local CD8+ T cells

Investigation of robust visual reaction and functional connectivity in the rat brain induced by rocuronium bromide with functional MRI

Functional magnetic resonance imaging (fMRI) has been used extensively to understand the brain function of a wide range of neurological and psychiatric disorders. When applied to animal studies, anesthesia is always used to reduce the movement of the animal and also reduce the impacts on the results of fMRI. Several awake models have been proposed by applying physical animal movement restrictions. However, restraining devices were designed for individual subject which limits the promotion of fMRI in awake animals. Here, a clinical muscle relaxant rocuronium bromide (RB) was introduced to restrain the animal in fMRI scanning time. The fMRI reactions of the animal induced with RB and the other two commonly used anesthesia protocols were investigated. The results of the fMRI showed that there were increased functional connectivity and well-round visual responses in the RB induced state. Furthermore, significant BOLD signal changes were found in the cortex and thalamus regions when the animal revived from isoflurane, which should be essential to further understand the effects of anesthesia on the brain. Keywords: Rocuronium bromide, isoflurane, animal anesthesia, fMRI, visual stimulation, resting stat

The caudal pedunculopontine tegmental nucleus may be involved in the regulation of skeletal muscle activity by melanocortin-sympathetic pathway: a virally mediated trans-synaptic tracing study in spinally transected transgenic mice

Understanding neuroanatomical sympathetic circuitry and neuronal connections from the caudal pedunculopontine tegmental nucleus to skeletal muscle is important to the study of possible mechanisms of pedunculopontine tegmental nucleus (PPTg) and cuneiform nucleus (CnF) that are involved in the regulation of skeletal muscle activity of the sympathetic pathway. The aim of this study was to use virus PRV-614 to trace the melanocortin-sympathetic neural pathways from PPTg and CnF to a hindlimb muscle (gastrocnemius) in spinally transected MC4R-GFP transgenic mice. PRV-614 was injected into the gastrocnemius muscle after receiving a complete spinal cord transection below the L2 level. PRV-614/MC4R-GFP and PRV-614/TPH dual-labeled neurons were found in the dissipated parts of PPTg (dpPPTg), but not between the compact parts of PPTg (cpPPTg) and CnF. It is proposed that a hierarchical pathway of neurons within the caudal pedunculopontine tegmental nucleus sends projections to the RVLM, which in turn projects onto the IML sympathetic preganglionic neurons that regulate muscle blood flow through melanocortin-sympathetic signals. Our results collectively indicate that MC4Rs expressed in caudal pedunculopontine tegmental nucleus may be involved in skeletal muscle activity of melanocortin-sympathetic pathways

Effects of the stem extracts of Schisandra glaucescens Diels on collagen-induced arthritis in Balb/c mice

Ethnopharmacological relevance Schisandra glaucescens Diels (SGD) is used in a subclass of traditional Chinese medicine known as “Tujia drugs”. It has been long used for the treatment of rheumatoid arthritis (RA), cough with dyspnea, spontaneous sweating, night sweating, chronic diarrhea, and neurasthenia. As a woody liana growing in mountain jungles at the altitudes of 750–1800 m, it is mainly distributed in Sichuan and Hubei Provinces of China. Aim of the study To evaluate the antiarthritic activity of acetate (EA) and n-butanol (Bu) fractions of SGD extract on a collagen-induced arthritis mice model. Materials and methods Acute toxicity of EA and Bu fractions of SGD extract was evaluated by gavage on normal mice. Pharmacological investigations were conducted on arthritis male Balb/c mice. The animal model was induced by immunization with type II bovine collagen (CII) on the 1st and the 14th day of the experimental schedule. EA fraction (104, 312, 936 mg/kg), Bu fraction (156, 469, 1407 mg/kg) of SGD extract was orally administered every two days since the 15th day for 3 weeks. Progression of edema in the paws was measured using a vernier caliper every 3 days since the 10th day. At the end of the experiment, the spleen index and histological changes of the hind knee joints were investigated. Additionally, to explore the possible antirheumatic mechanisms of the EA and Bu fractions, ELISA was carried out to analyze TNF-α, IL-10, IL-6 and IL-1β in the serum. Results The half lethal doses of both EA and Bu fractions were much higher than the dose administered in the pharmacological investigations. Oral administration of EA fraction and Bu fraction of SGD extract significantly and does-dependently inhibited type ІІ collagen induced arthritis (CIA) in mice, as indicated by the effects on paws swelling and spleen index. Histopathological examinations demonstrated that SGD effectively protected the bones and cartilages of knee joints from erosion, lesion and deformation. Besides, the serum concentrations of cytokines TNF-α, IL-1β and IL-6 were significantly lower than the ones from the vehicle control group. Respectively, while cytokine IL-10 was remarkably higher compare with the vehicle control group. Conclusions SGD might be a safe and effective candidate for the treatment of RA, and deserves further investigation on the chemical components in both EA and Bu fractions of SGD extract

Regional metabolic patterns of abnormal postoperative behavioral performance in aged mice assessed by 1H-NMR dynamic mapping method

Abstract Abnormal postoperative neurobehavioral performance (APNP) is a common phenomenon in the early postoperative period. The disturbed homeostatic status of metabolites in the brain after anesthesia and surgery might make a significant contribution to APNP. The dynamic changes of metabolites in different brain regions after anesthesia and surgery, as well as their potential association with APNP are still not well understood. Here, we used a battery of behavioral tests to assess the effects of laparotomy under isoflurane anesthesia in aged mice, and investigated the metabolites in 12 different sub-regions of the brain at different time points using proton nuclear magnetic resonance (1H-NMR) spectroscopy. The abnormal neurobehavioral performance occurred at 6 h and/or 9 h, and recovered at 24 h after anesthesia/surgery. Compared with the control group, the altered metabolite of the model group at 6 h was aspartate (Asp), and the difference was mainly displayed in the cortex; while significant changes at 9 h occurred predominantly in the cortex and hippocampus, and the corresponding metabolites were Asp and glutamate (Glu). All changes returned to baseline at 24 h. The altered metabolic changes could have occurred as a result of the acute APNP, and the metabolites Asp and Glu in the cortex and hippocampus could provide preliminary evidence for understanding the APNP process

Impact of malnutrition on propofol consumption and recovery time among patients undergoing laparoscopic gastrointestinal surgery

Background Malnutrition is a major health problem, especially in hospitalized patients as it can be closely related to many post-operative complications. However, research on malnutrition and its effect on the outcome of general anesthesia have been largely neglected. Here we investigated malnutrition status on propofol consumption and recovery time among patients undergoing laparoscopic gastrointestinal surgery under general anesthesia. Methods One hundred and one patients were recruited between January and June 2012 at Tongji Hospital and assigned into three groups according to Nutritional Risk Screening Tool 2002 score. A standard combined general anesthesia procedure was performed under regular monitoring. The dosage of propofol needed for induction, consumption during maintenance and recovery time were recorded. Results When compared with normal nutritional status individuals, the propofol dosage at induction was significantly decreased about 4.3% in moderate malnutritional status patients (P < 0.01) and about 16.8% in severely malnutritional status patients (P < 0.01). The average consumption of propofol was also significantly lower in malnourished individuals; for moderate malnutritional, the decrease was about 20% (P < 0.01) while for the severely malnutritional, it was 30% (P < 0.01) when compared with normal nutritional status individuals. For the recovery time of propofol anesthesia, the patients with severe malnutritional status awoke average 6.8 min later than those normally nourished (P < 0.01), but those patients with moderate malnutrition status did not (P = 0.885). Conclusion The present results indicate that the dosage and recovery time of propofol does change in malnourished individuals. Therefore, malnutrition may somehow affect the outcome of general anesthesia

PLGA-Curcumin Attenuates Opioid-Induced Hyperalgesia and Inhibits Spinal CaMKIIα.

Opioid-induced hyperalgesia (OIH) is one of the major problems associated with prolonged use of opioids for the treatment of chronic pain. Effective treatment for OIH is lacking. In this study, we examined the efficacy and preliminary mechanism of curcumin in attenuating OIH. We employed a newly developed PLGA-curcumin nanoformulation (PLGA-curcumin) in order to improve the solubility of curcumin, which has been a major obstacle in properly characterizing curcumin's mechanism of action and efficacy. We found that curcumin administered intrathecally or orally significantly attenuated hyperalgesia in mice with morphine-induced OIH. Furthermore, we demonstrated that the effects of curcumin on OIH correlated with the suppression of chronic morphine-induced CaMKIIα activation in the superficial laminae of the spinal dorsal horn. These data suggest that PLGA-curcumin may reverse OIH possibly by inhibiting CaMKIIα and its downstream signaling