ABSTRACT
Epilepsy is a prevalent and severe neurological disorder and approximately 30% of patients are resistant to existing medications. It is of utmost importance to develop alternative therapies to treat epilepsy. Schisandrin B (SchB) is a major bioactive constituent of Schisandra chinensis (Turcz.) Baill and has multiple neuroprotective effects, sedative and hypnotic activities. In this study, we investigated the antiseizure effect of SchB in various mouse models of seizure and explored the underlying mechanisms. Pentylenetetrazole (PTZ), strychnine (STR), and pilocarpine-induced mouse seizure models were established. We showed that injection of SchB (10, 30, 60 mg/kg, i.p.) dose-dependently delayed the onset of generalized tonic-clonic seizures (GTCS), reduced the incidence of GTCS and mortality in PTZ and STR models. Meanwhile, injection of SchB (30 mg/kg, i.p.) exhibited therapeutic potential in pilocarpine-induced status epilepticus model, which was considered as a drug-resistant model. In whole-cell recording from CHO/HEK-239 cells stably expressing recombinant human GABAA receptors (GABAARs) and glycine receptors (GlyRs) and cultured hippocampal neurons, co-application of SchB dose-dependently enhanced GABA or glycine-induced current with EC50 values at around 5 µM, and application of SchB (10 µM) alone did not activate the channels in the absence of GABA or glycine. Furthermore, SchB (10 µM) eliminated both PTZ-induced inhibition on GABA-induced current (IGABA) and strychnine (STR)-induced inhibition on glycine-induced current (Iglycine). Moreover, SchB (10 µM) efficiently rescued the impaired GABAARs associated with genetic epilepsies. In addition, the homologous mutants in both GlyRs-α1(S267Q) and GABAARs-α1(S297Q)ß2(N289S)γ2L receptors by site-directed mutagenesis tests abolished SchB-induced potentiation of IGABA and Iglycine. In conclusion, we have identified SchB as a natural positive allosteric modulator of GABAARs and GlyRs, supporting its potential as alternative therapies for epilepsy.
Subject(s)
Epilepsy , Lignans , Polycyclic Compounds , Receptors, Glycine , Mice , Animals , Humans , Pilocarpine/adverse effects , Strychnine/pharmacology , Strychnine/therapeutic use , Seizures/chemically induced , Seizures/drug therapy , Receptors, GABA-A , Glycine/pharmacology , Hypnotics and Sedatives , gamma-Aminobutyric Acid , CyclooctanesABSTRACT
OBJECTIVE@#To observe the effects of moxibustion on the stem cell factor (SCF)/tyrosine kinase receptor (c-kit) signaling pathway and immune function in rats with diarrhea irritable bowel syndrome (IBS-D), and to explore the mechanism of moxibustion for IBS-D.@*METHODS@#Among 52 young rats born from 6 healthy pregnant SPF rats, 12 rats were randomly selected into the normal group, and the remaining 40 rats were treated with the three-factor combination method of maternal separation, acetic acid enema and chronic restraint stress to establish the IBS-D rat model. Thirty-six rats with successful IBS-D model were randomly divided into a model group, a moxibustion group, and a medication group, 12 rats in each group. The rats in the moxibustion group were treated with suspension moxibustion at "Tianshu" (ST 25) and "Shangjuxu" (ST 37); the rats in the medication group were treated with intragastric administration of rifaximin suspension (150 mg/kg). All the treatments were given once a day for 7 consecutive days. The body mass, loose stool rate (LSR), the minimum volume threshold when abdominal withdrawal reflex (AWR) scored 3 were measured before acetic acid enema (35 days old), after modeling (45 days old), and after intervention (53 days old). After intervention (53 days old), HE staining was used to observe the morphology of colon tissue, and spleen and thymus coefficients were measured; ELISA method was used to detect serum inflammatory factors (tumor necrosis factor a [TNF-a], interleukin [IL]-10, IL-8), T-lymphocyte subsets (CD+4, CD+8, CD+45), value of CD+4/CD+8 and immune globulin (IgA, IgG, IgM); real-time PCR method and Western blot method was used to detect the expression of SCF, c-kit mRNA and protein in colon tissue; immunofluorescence staining method were used to detect positive expression of SCF and c-kit.@*RESULTS@#After intervention, compared with the normal group, in the model group, the body mass and the minimum volume threshold when AWR scored 3 were decreased (P<0.01), LSR, spleen and thymus coefficients, serum levels of TNF-α, IL-8, CD+4, CD+45, CD+4/CD+8, IgA, IgG, IgM were increased (P<0.01), serum IL-10 level and protein and mRNA expression of SCF and c-kit in colon tissue were decreased (P<0.01), and the positive expression of SCF and c-kit was decreased (P<0.01). Compared with the model group, in the moxibustion group and the medication group, the body mass and the minimum volume threshold when AWR scored 3 were increased (P<0.01, P<0.05), LSR, spleen and thymus coefficients, serum levels of TNF-α, IL-8, CD+4, CD+8, CD+45, CD+4/CD+8, IgA, IgG, IgM were decreased (P<0.01, P<0.05), serum IL-10 level and protein and mRNA expression of SCF and c-kit in colon tissue were increased (P<0.01), and the positive expression of SCF and c-kit was increased (P<0.01). Compared with the medication group, in the moxibustion group, the level of serum CD+4 was decreased (P<0.05), the value of CD+4/CD+8 was increased (P<0.01), and there was no significant difference in other indexes (P>0.05). The expression of SCF and c-kit mRNA was positively correlated with the minimum volume threshold when AWR scored 3 and IL-10 (P<0.01), and negatively correlated with remaining indexes (P<0.01, P<0.05).@*CONCLUSION@#Moxibustion could reduce visceral hypersensitivity, improve symptoms of abdominal pain and diarrhea in IBS-D rats, and its mechanism may be related to up-regulation of the expression of SCF/c-kit signaling pathway and improvement of IBS-D immune function.
Subject(s)
Rats , Animals , Irritable Bowel Syndrome/therapy , Moxibustion/methods , Rats, Sprague-Dawley , Interleukin-10 , Interleukin-8 , Maternal Deprivation , Tumor Necrosis Factor-alpha , Diarrhea , Signal Transduction , Homeostasis , Receptor Protein-Tyrosine Kinases , Immunity , Immunoglobulin A , Immunoglobulin MABSTRACT
OBJECTIVE@#To observe the effect of moxibustion on the regulation of nuclear factor-kappa B (NF-κB) and inflammatory factors by multiple microRNAs (miRNAs) in rats with diarrhea-predominant irritable bowel syndrome (IBS-D), and to explore the anti-inflammatory mechanism of moxibustion on IBS-D.@*METHODS@#Twelve of 52 newborn rats were randomly selected into a normal group. The remaining rats were made into IBS-D model. A total of 36 rats with successful model were randomly divided into a model group, a medication group and a moxibustion group, 12 rats in each group. The rats in the medication group were intraperitoneally injected with pyrrolidine dithiocarbamate (PDTC). The rats in the moxibustion group were treated with moxibustion at "Tianshu" (ST 25) and "Shangjuxu" (ST 37) for 20 min each time. All the intervention was given once a day for 7 days. Before and after modeling as well as after intervention, the body mass, loose stool rate and the minimum volume threshold of abdominal withdrawal reflex (AWR) were measured. After intervention, the contents of serum tumor necrosis factor α (TNF-α), interleukin (IL)-1β and IL-8 were detected by ELISA method; the morphology of colon tissues was observed by HE staining, and the expressions of miR-155, miR-125b, miR-29b, miR-31, miR-18a and NF-κB p65 mRNA in colon tissues were detected by real-time PCR. The expressions of NF-κB p65, TNF-α, IL-1β and IL-8 protein in colon tissues were detected by immunofluorescence.@*RESULTS@#After modeling, the body mass and the minimum volume threshold of AWR in the model group were lower than those in the normal group (P<0.01); the rates of loose stool in the model group were higher than those in the normal group (P<0.01); after intervention, in the model group, the inflammatory infiltration of colon tissues was obvious, and the serum levels of TNF-α, IL-1 β, IL-8 were higher than those in the normal group (P<0.05); the expression of miR-155, miR-125b, miR-29b, miR-31, miR-18a and NF-κB p65 mRNA in colon tissues was higher than that in the normal group (P<0.05); the protein expression of NF-κB p65, TNF-α, IL-1β, IL-8 was also higher than that in the normal group (P<0.01). After intervention, the body mass and the minimum volume threshold of AWR in the medication group and the moxibustion group were both higher than those in the model group (P<0.05); the loose stool rate in the medication group and the moxibustion group were lower than those in model group (P<0.05); the inflammatory cells infiltration in the colon tissues was less, the serum levels of TNF-α, IL-1β and IL-8 as well as the protein expression of NF-κB p65, TNF-α, IL-1β and IL-8 in the colon tissues in the medication group and the moxibustion group were lower than those in the model group (P<0.05, P<0.01). The expression of miR-125b, miR-31, miR-18a and NF-κB p65 mRNA in the medication group were lower than those in the model group (P<0.05). The expression of miR-155, miR-125b, miR-29b, miR-31, miR-18a and NF-κB p65 mRNA in the moxibustion group were lower than those in the model group (P<0.05). The miR-155, miR-125b, miR-29b, miR-31, miR-18a were positively correlated with NF-κB p65 mRNA (0<r<1, P<0.01).@*CONCLUSION@#The anti-inflammatory mechanism of moxibustion at "Tianshu" (ST 25) and "Shangjuxu" (ST 37) for IBS-D rats may be related to regulating multiple miRNAs to inhibit NF-κB signal pathway and reduce the expression of inflammatory factors.