OBJECTIVE: To investigate the effects of calcitonin gene-related peptide (CGRP) on autophagy in hypoxic/reoxygenated (H/R) cardiomyocytes and its relationship with the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway. METHODS: The rat cardiomyocyte cell line H9c2 was routinely cultured in vitro and passaged for experiments when the cells grew to 80% fusion. (1) CGRP dosage screening experiment: the cells were divided into blank control group, H/R group and different dosages of CGRP pretreatment groups. H9c2 cells were placed in a closed hypoxia chamber for 2 hours and then reoxygenated in a conventional incubator for 12 hours to prepare the H/R model. The CGRP pretreatment groups were pretreated with 0.01, 0.1, 0.5, 1, 5, and 10 μmol/L CGRP before the modeling process. The blank control group was not given any treatment. Cell counting kit-8 (CCK-8) was used to detect the cell survival rate, and the most suitable drug dosage was screened out. (2) Intervention experiment: H9c2 cells were divided into blank control group, H/R group, CGRP+H/R group, and CGRP+PI3K target inhibitor ly294002 (LY)+H/R group. H/R group was prepared as cellular H/R model. CGRP (1 μmol/L) alone or in combination with LY (10 μmol/L) was administered to CGRP+H/R group and CGRP+LY+H/R group, respectively, prior to the preparation of cellular H/R model. The blank control group was cultured routinely without treatment. The cell survival rate was detected by CCK-8. The level of lactate dehydrogenase (LDH) release was detected by colorimetric assay. The expressions of autophagy-related proteins [autophagy effector protein Beclin-1, microtubule-associated protein 1 light chain 3-II (LC3-II), autophagy protein p62] and PI3K/Akt/mTOR signaling pathway proteins [phosphorylated Akt (p-Akt), phosphorylated mTOR (p-mTOR)] were detected by Western blotting. RESULTS: (1) Results of CGRP dosage screening experiment: compared with the blank control group, the cell survival rate of the H/R group decreased significantly; and after giving 0.1, 0.5, 1, 5 μmol/L CGRP for pretreatment, the cell survival rate increased significantly, and intervention effect of 1 μmol/L CGRP was the best, and the difference was statistically significant when compared with that of the H/R group [(74.23±6.18)% vs. (23.43±4.09)%, P < 0.01], so it was used as the intervention dosage for the subsequent experiment. (2) Intervention experiment results: compared with the blank control group, the cell survival rate in the H/R group was significantly reduced, the level of LDH release was significantly increased, the protein expressions of Beclin-1 and LC3-II were significantly increased, and the protein expressions of p62, p-Akt and p-mTOR were significantly reduced, indicating that the death of cardiomyocytes occurred after the treatment of H/R and was accompanied by the elevation of autophagy level, and this process was associated with the activation of PI3K/Akt/mTOR signaling pathway. Compared with the H/R group, CGRP pretreatment increased cell survival rate [(76.02±2.43)% vs. (46.15±3.29)%, P < 0.01], decreased the level of LDH release (U/L: 169.83±11.65 vs. 590.17±34.50, P < 0.01), and down-regulated the protein expressions of Beclin-1 and LC3-II [Beclin-1 protein (Beclin-1/β-actin): 1.27±0.15 vs. 1.93±0.19, LC3-II protein (LC3-II/LC3-I): 1.27±0.13 vs. 1.98±0.18, both P < 0.01], up-regulated the protein expressions of p62, p-Akt, p-mTOR [p62 protein (p62/β-actin): 0.96±0.02 vs. 0.63±0.05, p-Akt protein (p-Akt/Akt): 0.76±0.04 vs. 0.48±0.02, p-mTOR protein (p-mTOR/mTOR): 1.13±0.09 vs. 0.68±0.15, all P < 0.05], suggesting that CGRP was able to reduce the H/R-induced cardiomyocyte injury, and this process was accompanied by a decrease in the level of cellular autophagy and activation of the PI3K/Akt/mTOR signaling pathway. Compared with the CGRP+H/R group, the cell survival rate was significantly lower than that in the CGRP+LY+H/R group [(56.95±6.63)% vs. (76.02±2.43)%, P < 0.01], LDH release level was significantly higher (U/L: 436.00±27.44 vs. 169.83±11.65, P < 0.01), and the protein expressions of Beclin-1 and LC3-II were significantly up-regulated [Beclin-1 protein (Beclin-1/β-actin): 1.63±0.12 vs. 1.27±0.15, LC3-II protein (LC3-II/LC3-I): 1.61±0.13 vs. 1.27±0.13, both P < 0.01], and significantly down-regulated p62, p-Akt, and p-mTOR protein expressions [p62 protein (p62/β-actin): 0.57±0.09 vs. 0.96±0.02, p-Akt protein (p-Akt/Akt): 0.45±0.01 vs. 0.76±0.04, p-mTOR protein (p-mTOR/mTOR): 0.66±0.06 vs. 1.13±0.09, all P < 0.05], suggesting that PI3K-targeted inhibitor was able to reverse the protective effect of CGRP on H/R cells. CONCLUSIONS CGRP pretreatment attenuated H/R-induced cardiomyocyte injury, increased cell survival rate, and reduced cellular LDH release. This effect may be achieved through inhibiting the activation of PI3K/Akt/mTOR signaling pathway.
Animals ; Myocytes, Cardiac/drug effects* ; Signal Transduction/drug effects* ; Rats ; TOR Serine-Threonine Kinases/metabolism* ; Calcitonin Gene-Related Peptide/pharmacology* ; Proto-Oncogene Proteins c-akt/metabolism* ; Autophagy/drug effects* ; Cell Line ; Cell Hypoxia ; Phosphatidylinositol 3-Kinases/metabolism*

Cancer pain is one of the most common symptoms in patients with advanced cancer. In this study, we aimed to investigate the effects of the Mas-related gene C (MrgC) receptors on bone cancer pain. Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured after the inoculation of Walker 256 mammary gland carcinoma cells into the tibia of adult Sprague-Dawley rats. The effects of MrgC receptor agonist bovine adrenal medulla 8-22 (BAM8-22) on nociceptive behaviors were investigated after intrathecal injection on days 16 and 17. Glial fibrillary acidic protein (GFAP)-positive cells in the spinal dorsal cord, and calcitonin gene related peptide (CGRP)-, neuronal nitric oxide synthase (nNOS)- and IL-1β-positive neurons in the dorsal root ganglia (DRG) were examined by immunofluorescence staining. The expression of nNOS and IL-1β proteins in the spinal dorsal horn and the DRG was examined by Western blotting after treatment with (Tyr6)-γ2-MSH-6-12 (MSH), which was another MrgC receptor agonist. The results showed that intrathecal injection of BAM8-22 (30 nmol) attenuated mechanical allodynia in a rat model of bone cancer pain and the effects could last for about 60 min, and single administration of BAM8-22 for two consecutive days reduced mechanical allodynia by about half on the third day. Moreover, the number of GFAP-positive cells in the spinal dorsal horn, and the number of CGRP-, nNOS- and IL-1β-positive neurons in the DRG were decreased. Similarly, intrathecal administration of MSH (15 nmol) reduced the expression of nNOS and IL-1β in the spinal dorsal horn and the DRG. In conclusion, activation of MrgC receptors suppresses the activation of astrocytes in the spinal dorsal cord and the expression of CGRP, nNOS, and IL-1β in the spinal dorsal cord and/or DRG, which may underlie the inhibition of bone cancer pain. These findings provide a novel strategy for the treatment of bone cancer pain.
Animals ; Cancer Pain/drug therapy* ; Rats ; Rats, Sprague-Dawley ; Bone Neoplasms/complications* ; Ganglia, Spinal/metabolism* ; Spinal Cord Dorsal Horn/metabolism* ; Receptors, G-Protein-Coupled/genetics* ; Female ; Calcitonin Gene-Related Peptide/genetics* ; Interleukin-1beta/metabolism* ; Peptide Fragments/metabolism* ; Nitric Oxide Synthase Type I/genetics* ; Disease Models, Animal

This study investigated the neuroprotective effects and underlying mechanism of Liujing Toutong Tablets(LJTT) on a rat model of permanent middle cerebral artery occlusion(pMCAO). The pMCAO model was established using the suture method. Eighty-four male SPF-grade SD rats were randomly divided into a sham operation group, a model group, a nimodipine group(0.020 g·kg~(-1)), and high-, medium-, and low-dose LJTT groups(2.8, 1.4, and 0.7 g·kg~(-1)). The Longa score, adhesive removal test and laser speckle contrast imaging technique were used to evaluate the degree of neurological functional impairment and changes in local cerebral blood flow. The survival and mortality of rats in each group were recorded daily. After seven days of continuous administration following the model induction, the rats in each group were euthanized, and brain tissue and blood samples were collected for corresponding parameter measurements. Nissl staining was used to examine pathological changes in brain tissue neurons. The levels of tumor necrosis factor-alpha(TNF-α), interleukin-6(IL-6), IL-1β, vascular endothelial growth factor(VEGF), calcitonin gene-related peptide(CGRP), beta-endorphin(β-EP), and endogenous nitric oxide(NO) in rat serum were measured using specific assay kits. The entropy weight method was used to analyze the weights of various indicators. The protein expression levels of nuclear factor kappa-B(NF-κB), inhibitor kappaB alpha(IκBα), phosphorylated IκBα(p-IκBα), and phosphorylated inhibitor of NF-κB kinase alpha(p-IKKα) in brain tissue were determined using Western blot. Immunohistochemistry was used to detect the protein expression of chemokine-like factor 1(CKLF1) and C-C chemokine receptor 5(CCR5) in rat brain tissue. Compared with the sham operation group, the model group showed significantly higher neurological functional impairment scores, prolonged adhesive removal time, decreased cerebral blood flow, increased neuronal damage, reduced survival rate, significantly increased levels of TNF-α, IL-1β, IL-6, CGRP, and NO in serum, significantly decreased levels of VEGF and β-EP, significantly increased expression levels of NF-κB p65, p-IκBα/IκBα, and p-IKKα in rat brain tissue, and significantly upregulated protein expression of CKLF1 and CCR5. Compared with the model group, the high-dose LJTT group significantly improved the neurological functional score of pMCAO rats after oral administration for 7 days. LJTT at all doses significantly reduced adhesive removal time and restored cerebral blood flow. The high-and medium-dose LJTT groups significantly improved neuronal damage. The LJTT groups at all doses showed reduced levels of TNF-α, IL-1β, IL-6, CGRP, and NO in rat serum, increased VEGF and β-EP levels, and significantly decreased expression levels of NF-κB p65, p-IκBα/IκBα, p-IKKα, and CCR5 protein in rat brain tissue. The entropy weight analysis revealed that CGRP and β-EP were significantly affected during the model induction, and LJTT exhibited a strong effect in reducing the release of inflammatory factors such as TNF-α and IL-1β. LJTT may exert a neuroprotective effect on rats with permanent cerebral ischemia by reducing neuroinflammatory damage, and its mechanism may be related to the inhibition of the NF-κB signaling pathway and the regulation of the CKLF1/CCR5 axis. Additionally, LJTT may exert certain analgesic effects by reducing CGRP and NO levels and increasing β-EP levels.
Rats ; Male ; Animals ; NF-kappa B/metabolism* ; NF-KappaB Inhibitor alpha/metabolism* ; Vascular Endothelial Growth Factor A/genetics* ; I-kappa B Kinase/pharmacology* ; Tumor Necrosis Factor-alpha/pharmacology* ; Interleukin-6/genetics* ; Calcitonin Gene-Related Peptide/pharmacology* ; Rats, Sprague-Dawley ; Signal Transduction ; Brain Ischemia/drug therapy* ; Tablets

Our previous studies have shown that calcitonin gene-related peptide (CGRP) exerts protective effects on the acute lung injury induced by oxidative stress. This study was aimed to investigate whether autophagy was involved in the protection of CGRP against oxidative stress-induced lung injury in neonatal rats. Newborn Sprague-Dawley (SD) rats were randomly divided into five groups: Control group, oxidative stress model group (Model group), Model + CGRP group, Model + CGRP + Rapamycin (an autophagy agonist) group, and Model + CGRP + LY294002 (an autophagy inhibitor) group. The model of hyperoxia-induced lung injury was established by continuous inhalation of oxygen (FiO₂ = 90%-95%) for 14 days in neonatal SD rats. Pathological changes of lung tissue were observed by hematoxylin and eosin (HE) staining, and mean linear intercept (MLI) was measured. The quantitative changes of autophagic vesicles (AV) in type II alveolar epithelial cells (AECII) were measured under the transmission electron microscope. The protein expressions of Caspase-3, Bcl-2, mTOR, and Beclin-1 in lung tissue lysates were detected by Western blot. The results showed that, compared to the Model group at the same time point, the number of AV in AECII and the expression level of Beclin-1 protein of the lung tissue were increased, while the expression level of mTOR protein was decreased, with alleviated pathological changes, reduced MLI value and Caspase-3 protein expression level, increased Bcl-2 protein expression level in the lung tissue of Model + CGRP group. In addition, we found that the protective effect of CGRP on hyperoxia-induced lung injury could be enhanced by autophagy activator Rapamycin and abolished by autophagy inhibitor LY294002. Together, these findings indicate that CGRP could attenuate hyperoxia-induced lung injury in neonatal rats by enhancing autophagy.
Acute Lung Injury/pathology* ; Animals ; Animals, Newborn ; Autophagy ; Calcitonin/metabolism* ; Calcitonin Gene-Related Peptide/metabolism* ; Caspase 3/metabolism* ; Hyperoxia/pathology* ; Lung/pathology* ; Lung Injury/prevention & control* ; Oxidative Stress ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Rats ; Rats, Sprague-Dawley ; Sirolimus/pharmacology*

OBJECTIVE: To investigate the changes of skin temperature, blood infusion and inflammatory cytokines of cutaneous tissue in the sensitized area of colitis model rats, as well as the relationship between sensory and sympathetic nerves and the formation of sensitized area, and to initially reveal the partial physical-chemical characteristics of the sensitized area in the colitis model rats. METHODS: Thirty-five male SD rats were randomly divided into a control group (n=10), a model group (n=18) and a guanethidine group (n=7). 5% dextran sulfate sodium (DSS) was adopted for 6-day free drinking to establish colitis model in the model group and the guanethidine group. On day 6 and 7, in the guanethidine group, guanethidine solution (30 mg/kg) was injected intraperitoneally for sympathetic block. On day 7, after injection of evans blue (EB) solution, the EB extravasation areas on the body surface were observed to investigate the distribution and physical-chemical characteristics of the sensitized area. The control area was set up, 0.5 cm away from the sensitized area, and with the same nerve segment innervation. Disease activity index (DAI) score of rats was compared between the normal group and the model group, and the morphological changes in the colon tissue were investigated with HE method. Using infrared thermal imaging technology and laser speckle flow imaging technology, skin temperature and blood infusion were determined in the sensitized area and the control area of the rats in the model group. Immunofluorescence technique was adopted to observe the expression levels of the positive nerve fibers of substance P (SP), calcitonin gene-related peptide (CGRP) and tyrosine hydroxylase (TH), and the correlation with blood vessels; as well as the expression levels of SP positive nerve fibers/tryptase⁺ mast cells, and tryptase⁺ mast cells/5-hydroxytryptamine (5-HT) in skin tissue in the sensitized area and the control area of the rats in the model group. MSD multi-level factorial method and ELISA were applied to determine the contents of pro-inflammatory and anti-inflammatory cytokines (e.g. TNF-α, IL-1β, IL-6, IL-4 and IL-10) and anti-inflammatory substance corticosterone (CORT). RESULTS: Sensitization occurred at the T₁₂-S₁ segments of the colitis model rats, especially at L₂-L₅ segments. Compared with the normal group, DAI score was increased in the rats of the model group (P<0.05), and the colonic mucosal damage was obvious, with the epithelial cells disordered, even disappeared, crypt destructed, submucosal edema and a large number of inflammatory cells infiltrated. In comparison with the control area, the skin temperature and blood infusion were increased in the sensitized area of the model group (P<0.05, P<0.01); as well as the expression levels of the positive nerve fibers of SP, CGRP and TH of skin tissue (P<0.05), which was specially distributed in peripheral vessels, the expression levels of SP positive nerve fibers/tryptase⁺ mast cells, and tryptase⁺ mast cells/5-HT of the skin tissue were all expanded (P<0.05) in the sensitized area of the model group. Compared with the model group, the number of sensitized areas was reduced in the guanethidine group (P<0.05). In comparison with the control area of the model group, in the sensitized area, the contents of pro-inflammatory cytokines, e.g. TNF-α, IL-1β and IL-6, and the anti-inflammatory substance CORT of skin tissue were all increased (P<0.05); and the contents of IL-6 and TNF-α were negatively correlated with CORT (P<0.05). CONCLUSION The sensitized areas on the body surface of colitis rats are mainly distributed in the L₂-L₅ segments. Sensory and sympathetic nerves are involved in the acupoint sensitization, and the sensitized areas may have the dynamic changes in pro-inflammatory and anti-inflammatory substances.
Animals ; Anti-Inflammatory Agents ; Calcitonin Gene-Related Peptide/metabolism* ; Colitis/metabolism* ; Cytokines/metabolism* ; Guanethidine ; Interleukin-6 ; Male ; Rats ; Rats, Sprague-Dawley ; Serotonin ; Skin Temperature ; Substance P/genetics* ; Tryptases ; Tumor Necrosis Factor-alpha

OBJECTIVE: To discuss the clinical significance of antibacterial peptide LL-37 in the early diagnosis of patients with sepsis in emergency department. METHODS: Forty patients diagnosed with sepsis in the emergency department of the Affiliated Hospital of Zunyi Medical College from December 2017 to March 2018 were enrolled as sepsis group. Twenty healthy volunteers were enrolled contemporaneously in our hospital at medical center as healthy control group. Peripheral blood was collected immediately after diagnosis in sepsis group or during physical examination in healthy control group. The expression of antibacterial peptide LL-37 was determined by enzyme-linked immunosorbent assay (ELISA). Meanwhile, serum procalcitonin (PCT) and C-reactive protein (CRP) levels were determined. The differences in antibacterial peptide LL-37, PCT and CRP levels between the two groups were compared. Pearson correlation method was used to analyze the correlation between antibacterial peptide LL-37, PCT and CRP. Receiver operating characteristic (ROC) curve was drawn, and the early individually or jointly diagnostic value of each detected index for sepsis was analyzed. RESULTS: The levels of antimicrobial peptide LL-37, PCT and CRP in peripheral blood of sepsis group were significantly higher than those of healthy control group [LL-37 (μg/L): 1.34±0.69 vs. 0.10±0.06, PCT (μg/L): 46.67±39.51 vs. 0.03±0.02, CRP (mg/L): 129.68±49.83 vs. 3.16±2.85], with statistically significant differences (all P < 0.05). Pearson correlation analysis showed that the expression of antimicrobial peptide LL-37 was positively correlated with PCT and CRP levels (r₁ = 0.835, r₂ = 0.932, both P < 0.01). ROC curve analysis showed that the area under ROC curve (AUC) of LL-37, PCT and CRP for early diagnosis of sepsis was 0.885, 0.963 and 0.983, respectively, and the AUC of combined diagnosis of the three parameters was as high as 0.994, indicating that the value of combined diagnosis of sepsis was greater than that of single diagnosis; when the combined prediction probability of the three parameters was 0.92, the sensitivity was 97.5%, and the specificity was 95.0%. CONCLUSIONS Antibacterial peptide LL-37 has certain clinical value in early diagnosis of patients with sepsis, which can be used as early routine monitoring indicators for patients with early sepsis when combined with PCT and CRP.
Antimicrobial Cationic Peptides/metabolism* ; C-Reactive Protein ; Calcitonin ; Calcitonin Gene-Related Peptide ; Early Diagnosis ; Emergency Service, Hospital ; Humans ; Protein Precursors ; ROC Curve ; Sepsis/metabolism* ; Cathelicidins

PURPOSE: The pathophysiology of discogenic low back pain is not fully understood. Tetrodotoxin-sensitive voltage-gated sodium (NaV) channels are associated with primary sensory nerve transmission, and the NaV1.7 channel has emerged as an analgesic target. Previously, we found increased NaV1.7 expression in dorsal root ganglion (DRG) neurons innervating injured discs. This study aimed to examine the effect of blocking NaV1.7 on sensory nerves after disc injury. MATERIALS AND METHODS: Rat DRG neurons innervating the L5/6 disc were labeled with Fluoro-Gold (FG) neurotracer. Twenty-four rats underwent intervertebral disc puncture (puncture group) and 12 rats underwent sham surgery (non-puncture group). The injury group was divided into a saline infusion group (puncture+saline group) and a NaV1.7 inhibition group, injected with anti-NaV1.7 antibody (puncture+anti-NaV1.7 group); n=12 per group. Seven and 14 days post-surgery, L1 to L6 DRGs were harvested and immunostained for calcitonin gene-related peptide (CGRP) (an inflammatory pain marker), and the proportion of CGRP-immunoreactive (IR) DRG neurons of all FG-positive neurons was evaluated. RESULTS: The ratio of CGRP-IR DRG neurons to total FG-labeled neurons in the puncture+saline group significantly increased at 7 and 14 days, compared with the non-puncture group, respectively (p<0.05). Application of anti-NaV1.7 into the disc significantly decreased the ratio of CGRP-IR DRG neurons to total FG-labeled neurons after disc puncture at 7 and 14 days (40% and 37%, respectively; p<0.05). CONCLUSION: NaV1.7 antibody suppressed CGRP expression in disc DRG neurons. Anti-NaV1.7 antibody is a potential therapeutic target for pain control in patients with lumbar disc degeneration.
Animals ; Antibodies ; Calcitonin Gene-Related Peptide/metabolism ; Disease Models, Animal ; Ganglia, Spinal/*metabolism ; Intervertebral Disc/*drug effects/*injuries ; Intervertebral Disc Degeneration/metabolism ; Low Back Pain/*physiopathology ; Lumbar Vertebrae/injuries ; Male ; NAV1.7 Voltage-Gated Sodium Channel/*metabolism ; Neurons/*metabolism ; Pain/metabolism ; Rats ; Rats, Sprague-Dawley ; Stilbamidines

OBJECTIVEPrevious studies have clarified that calcitonin gene-related peptide (CGRP) can promote the biologi- cal activity of osteoblasts. To further reveal the role of CGRP in bone repair, we studied its influence on osteogenic differentia- tion of mouse bone marrow stromal cells (BMSCs) and initially explored the effect of the Hippo signaling pathway with this process.

METHODSBMSCs were induced to osteogenic differentiate osteoblasts by different concentrations of CGRP for a screening of the optimal concentration. CGRP was added in BMSCs, then the activity of alkaline phosphatase (ALP) and the number of mineralized nodules were examined by specific ALP kits after 48 hours and alizarin red staining fluid after 7 days, respectively. The protein expression of p-Mst1/2 was measured by Western blot. Verteporfin was used to block the downstream Yap signaling. The mRNA expression of collagen type I (Col I) and runt-related transcription factor 2 (Runx2) were detected by reverse transcription-polymerase chain reaction.

RESULTSCompared to the blank group, different concentrations of CGRP (10⁻⁹, 10⁻⁸, 10⁻⁷ mol · L⁻¹), especially 10⁻⁸ mol · L⁻¹, significantly increased the ALP activity of BMSCs (P < 0.05). Alizarin red staining also showed more mineralized nodules in 10⁻⁸ mol · L⁻¹ group. The expression of p-Mst1/2 increased in the CGRP group (P < 0.05). Verteporfin treatment effectively decreased the mRNA expression of Runx2 and Col I (P < 0.05).

CONCLUSIONThe Hippo signaling pathway plays a role in CGRP-induced osteogenic differentiation in mouse BMSCs.

Alkaline Phosphatase ; Animals ; Calcitonin ; genetics ; metabolism ; Calcitonin Gene-Related Peptide ; metabolism ; Cell Differentiation ; Cells, Cultured ; Collagen Type I ; Core Binding Factor Alpha 1 Subunit ; Mesenchymal Stromal Cells ; physiology ; Mice ; Osteoblasts ; Osteogenesis ; physiology ; Signal Transduction

Lumbar disc herniation is commonly encountered in clinical practice and can induce sciatica due to mechanical and/or chemical irritation and the release of proinflammatory cytokines. However, symptoms are not confined to the affected spinal cord segment. The purpose of this study was to determine whether multisegmental molecular changes exist between adjacent lumbar spinal segments using a rat model of lumbar disc herniation. Twenty-nine male Sprague-Dawley rats were randomly assigned to either a sham-operated group (n=10) or a nucleus pulposus (NP)-exposed group (n=19). Rats in the NP-exposed group were further subdivided into a significant pain subgroup (n=12) and a no significant pain subgroup (n=7) using mechanical pain thresholds determined von Frey filaments. Immunohistochemical stainings of microglia (ionized calcium-binding adapter molecule 1; Iba1), astrocytes (glial fibrillary acidic protein; GFAP), calcitonin gene-related peptide (CGRP), and transient receptor potential vanilloid 1 (TRPV1) was performed in spinal dorsal horns and dorsal root ganglions (DRGs) at 10 days after surgery. It was found immunoreactivity for Iba1-positive microglia was higher in the L5 (P=0.004) dorsal horn and in the ipsilateral L4 (P=0.009), L6 (P=0.002), and S1 (P=0.002) dorsal horns in the NP-exposed group than in the sham-operated group. The expression of CGRP was also significantly higher in ipsilateral L3, L4, L6, and S1 segments and in L5 DRGs at 10 days after surgery in the NP-exposed group than in the sham-operated group (P<0.001). Our results indicate that lumbar disc herniation upregulates microglial activity and CGRP expression in many adjacent and ipsilateral lumbar spinal segments.
Animals ; Astrocytes/metabolism ; Calcitonin Gene-Related Peptide/*metabolism ; Calcium-Binding Proteins/*metabolism ; Disease Models, Animal ; Ganglia, Spinal/metabolism ; Humans ; Immunohistochemistry ; Intervertebral Disc Displacement/*metabolism ; Lumbar Vertebrae/*metabolism ; Male ; Microfilament Proteins/*metabolism ; Microglia/metabolism ; Neuralgia/metabolism ; Rats ; Rats, Sprague-Dawley ; Spinal Cord Dorsal Horn/metabolism ; Up-Regulation

The present study aims to investigate the kinetic histocytochemical changes of acupoints in different condition. The expression of tryptase (+) mast cells, histamine (HA) , serotonin (5-HT) and nociceptive neuropeptides including calcitonin gene-related peptide (CGRP) and substance P (SP) were observed by immunohistochemistry combined with confocal technology. Mast cells were labeled with anti-mast cell tryptase antibody and simultaneously with HA or 5-HT primary antibodies to observe their co-expression. The results showed that: (1) SP and CGRP were expressed more highly on the cutaneous nerve fibers of "Hegu" (LI 4) after acupuncture stimulation than that of the control. Mast cells aggregated in close proximity to the blood vessels in intra-epidermis and dermis, and some of them with degranulation in the lower dermis and subcutaneous tissue of "Hegu" (LI 4). Both mast cells and their granules appeared with HA (+) and 5-HT (+) expression at stimulated LI 4 sites, while a few intact mast cells with a little expression of 5-HT and HA were distributed in areas of non-stimulated Ll 4. (2) The acupoints in different locations such as Baihui (GV 20), Weishu (BL 21), Zhongwan (CV 12) and LI 4 had the same constituent but the contents were different. (3) The histocytochemical responses of acupoints sensitized by the Gastric mucosa injury (GMI) were also investigated. GMI resulted in neurogenic plasma extravasation by Evans Blue (EB) in the skin of the acupoints over the back and abdomen, which mostly occurred in the T9-T11 dermatomere. The EB extravasation dots just like acupoints sensitization appeared after GMI and disappeared gradually during the natural self-recovery of the gastric mucosa. More SP and CGRP positive nerve fibers were distributed in EB dots than in regions beside EB dots and in the control, mostly distributed in the nerve fibers around both the vessels and root of hair follicle. Mast cells also aggregated and degranulated to release algogenic substances of 5-HT and HA around the vessels in areas of the EB dots. Collectively the acupoints displayed the same histocytochemical responses due to either acupuncture stimulation or GMI. This may potentially be the histocytochemical basis in the local acupoints and acupoints displayed kinetic changes in different condition.
Acupuncture Points ; Acupuncture Therapy ; Animals ; Calcitonin Gene-Related Peptide ; metabolism ; Gastric Mucosa ; chemistry ; metabolism ; Histocytochemistry ; Humans ; Mast Cells ; chemistry ; metabolism ; Mice ; Rats ; Serotonin ; metabolism ; Skin ; chemistry ; metabolism ; Substance P ; metabolism