Abstract： Objective To investigate the acute cardioprotective effect of 17b-estradiol (17b-E2) against severe myocardial ischemia/reperfusion (I/R) injury in rabbits and the mechanism of the effect. Methods We established the model of myocardial I/R in vivo by occluding the left anterior descending coronary artery of the rabbits (who underwent coronary occlusion for 40 minutes followed by 3 hours of reperfusion). Twentyfour New Zealand white male rabbits were randomly divided into two groups with 12 in each group. Before coronary occlusion, 1 ml of ethanol or 17b-E2 at 10 μg/kg was administered intravenously to the rabbits in the control group and the experimental group respectively. The serum levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured by enzymelinked immunosorbent assay (ELISA) at the following time points: before occlusion, 40 minutes after occlusion, 1 hour, 2 hours and 3 hours after reperfusion. Activation of p38 mitogen activated protein kinase(MAPK) was determined by Western blotting analysis, and apoptosis of cardiocytes was identified by terminal deoxynucleotidlyl transferase mediated deoxyuridinebiotin dUTP Nick End Labeline (TdT)mediated dNTP nick end labeling (TUNEL) staining. Results During myocardial ischemia, TNF-α decreased significantly in the experimental group compared with the control group (F=0.007,P=0.001), while there was no difference in IL-6 between the two groups (F=0.616,P=0.095). During the process of reperfusion, the levels of TNF-α and IL-6 in the experimental group were significantly lower than those in the control group (Plt;0.01). Besides, the activation of p38 MAPK and apoptotic index for the experimental group were also lower (45.07%±2.73% vs. 61.25%±2.41%, t＝－15.398, P=0.000; 11.21%±3.85% vs. 22.02%±4.49%, t＝－6.332, P=0.000). Conclusion The cardioprotective effect of 17b-E2 against myocardial I/R may be attributed to its antiinflammatory and antiapoptotic properties, which is probably associated with the inhibition of 17bE2 on p38MAPK activity.
Objective To investigate the gene expression of p38mitogen-activated protein kinase (p38MAPK) and its upstream signaling molecule (mkk3 and mkk6) in fetal skin at different developmental stages and postnatal skin and its potential biological significance. Methods The fetal skin biopsies were obtained from human embryo of spontaneous abortion at gestational ages from 13 to 32 weeks and postnatal skin specimens were collected from patients(4-16 years) undergoing plastic surgery. After the morphological characteristics of skins at different developmental stages were detected with pathological methods, the gene expressions of p38MAPK, mkk3 and mkk6 in skins were examined with reverse transcriptionpolymerase chain reaction analysis (RT-PCR). Results The gene expressions of p38MAPK, mkk3 and mkk6 could all be detected in fetal and postnatal skins. In fetal skins, these 3 genes were bly expressed. Along with fetal growth and development, the gene expressions of p38MAPK and its upstream signaling molecules were faded gradually. In postnatal skin, the mRNA contents of these 3 genes were significantly decreased in comparison with those in fetal skin (Plt;0.01). Conclusion p38 MAPK mediated signal pathways might be involved in the skin developmentat embryonic stage and in the determination of cutaneous structure and function, and also in wound healing at postnatal stage. The relative increment of these gene transcription in younger fetal skin might be one of the reasons why cutaneous cells proliferate rapidly and the wounds heal without scar.
Epilepsy is a disorder of the brain in which sudden abnormal discharges of neurons cause transient dysfunction and is a common disorder of the nervous system. Although most patients experience remission of symptoms with medication, about 20 ~ 30% of patients still have poor outcomes with medication and progress to refractory epilepsy. The etiology of epilepsy is complex and the exact pathogenesis is not yet clear. Current research has explored the pathophysiological mechanisms underlying epileptogenesis, thus providing a basis for identifying potential therapeutic targets for epilepsy and advancing the precision treatment of epilepsy. p38 Mitogen-activated protein kinase (MAPK) signalling pathway is a conserved class of kinases involved in many physiological/pathological processes by regulating intracellular gene expression levels, cell division, differentiation and apoptosis in response to various extracellular stimuli in order to mediate intracellular signalling cascades. The p38 MAPK signalling pathway is one of the subfamilies of MAPK that mediates inflammatory responses, apoptosis, tissue edema and other biological processes involved in the development of central nervous system diseases. The p38 MAPK signalling pathway is now reviewed for its involvement in the development of epilepsy through unused pathways, in order to identify new potential targets for epilepsy treatment and provide clinical precision.
ObjectiveTo investigate the effect of erigeron breviscapus (EBHM) on ocular hypertension and the protective effect of retinal ganglion cells (RGCs) in rats by regulating mitogen activated protein kinase (MAPK) signaling pathway.MethodsSixty male Sprague-Dawley rats were divided into control group, model group, low-dose EBHM group (group A), medium-dose EBHM group (group B), and high-dose EBHM group (group C) by random number table method. There were 12 rats in the group, the left eye was used as the experimental eye. The rats of model group, group A, group B, and group C were infused with normal saline through the anterior chamber to construct an acute ocular hypertension model; the control group was given general anesthesia only. Then, 2-30 days after modeling, rats in the control group and model group were given 3 ml of normal saline once a day; rats in group A, group B, and group C were given 0.30, 0.45, and 0.60 g/100 g EBHM by intragastric administration, respectively, 1 time/d. The rat intraocular pressure was measured before modeling and 1, 14, and 30 days after modeling, and the proportion of high intraocular pressure model was measured. Thirty days after modeling, hematoxylin-eosin (HE) staining was used to observe the pathological changes of retinal tissue; immunofluorescence staining was used to detect the changes in the number of RGCs; real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) was used to detect p38 in the retinas of rats in each group. The relative expression of MAPK and Caspase-3 mRNA; western blot was used to detect p38MAPK and phosphorylation in the retina of rats in each group relative expression of phosphorylate-p38MAPK (p-p38MAPK) and Caspase-3 protein. One-way analysis of variance was used for multi-sample comparison, and SNK-q test was used for comparison between two samples.ResultsOne day after modeling, none of the rats in the control group developed acute ocular hypertension, and the other groups were successfully modeled. Compared with the model group, the rates of acute ocular hypertension at 14 days after modeling in groups B and C were lower (χ2=98.701, P＜0.05), and the rates of acute ocular hypertension at 30 days after modeling in groups A, B, and C were 0. There was no statistically significant difference in the rates of acute ocular hypertension between 14 and 30 days after modeling in the A, B, and C groups (P＞0.05). The results of HE staining showed that the structure of the retina in the control group was complete, and the layers were clearly visible; the RGCs count was not abnormal, and the morphology was plump and round. The retina of rats in the model group became thinner; the number of RGCs was greatly reduced, the morphology was vacuolated, and the arrangement was sparse. The retina of rats in groups A, B, and C became thicker, and the number of RGCs increased, and the retina structure in group C was better restored. The results of immunofluorescence staining showed that the RGCs counts of rats in groups A, B, and C were higher than those in the model group, and the difference was statistically significant (F=297.514, P＜0.05); pairwise comparison between groups, group A was lower than that of group B and C Group (q=2.842, 5.263), group B was lower than group C (q=2.457), the difference was statistically significant (P＜0.05). The results of RT-qPCR and Western blot showed that compared with the model group, the relative expression of Caspase-3 mRNA (F=267.912) and protein (F=692.279) and the relative expression of p-p38MAPK protein in the retina of rats in groups A, B and C. The expression level (F=150.061) all decreased, and the difference was statistically significant (P＜0.05); pairwise comparisons between groups showed that Caspase-3 mRNA (q=6.977, 15.642) and protein (q=6.997, 15.642) relative expression levels and p-p38MAPK protein (q=12.443, 24.358) relative expression levels are lower than groups A and B, group B was lower than group A (q=11.678, 12.471, 10.204), the difference was statistical academic significance (P＜0.05).ConclusionsEBHM can significantly reduce intraocular pressure in rats with acute ocular hypertension, increase RGCs counts, and reduce retinal damage. Its regulatory mechanism may be related to the MAPK pathway.
Objective To investigate whether Chlamydia pneumoniae alters the expression of TLR2 mRNA and p38 MAPK mRNA in mice with Chlamydia pneumoniae infection in TLR2-p38 MAPK-dependent pathway, subsequently leading to the release of cytokines. Methods Seventy-two male C3H/HeJmice were randomly divided into three groups as follow: a normal control group, a C. pneumoniae-inoculated group, and a C. pneumoniae-inoculated with SB203580 treatment group. The mice in the three groups were sacrificed on 1st, 4th, 7th, 14th day separately, and lung tissues were sampled for measurement. The expression changes of TLR2 mRNA and p38 MAPK mRNA in the mice lung tissue were measured by semi-quantitative RT-PCR. The concentrations of TNF-αin the lung tissue were measured by ELISA.Results Compared with those in the normal group, the expressions of TLR2 mRNA and p38MAPK mRNA in the lung tissue increased quickly after C. pneumoniae infection, which was especially obvious on day 4 and on day 7, the expression level of TLR2 mRNA on day 7 was markedly higher than that of the normal group [ ( 7. 24 ±1. 78) mg/L vs.( 0. 64 ±0. 14) mg/L, P lt;0. 05] ; The expression level of p38 MAPK mRNA on day 4 was markedly higher than that of the normal group [ ( 9. 267 ±1. 813) mg/L vs. ( 3. 734 ±0. 946) mg/L, P lt;0. 05] . After 14 days, C. pneumoniae infection of mice was attenuated, the concentration of TNF-α in the lung tissue increased, and was clearly higher than that of the normal control group, peaking on day 4 [ ( 77. 29 ±9. 66) pg/mg] . Treatment with SB203580 could effectively inhibit TLR2 mRNA and p38 MAPK mRNA expression in lung, which was especially obvious on day 4 and on day 7. The expression level of TLR2 mRNA on day 7 was ( 0. 269 ±0. 09) mg/L, and the expression level of p38 MAPK mRNA on day 7 [ ( 0. 002 ±0. 001) mg/L] was even more obviously attenuated, the concentration of TNF-α in the lung tissue markedly decreased when compared with that in the infected group, and its concentration on day 4 [ ( 25. 76 ±3. 49) pg/mg] lowered more clearly. Conclusions The alteration of TLR2-p38 MAPKdependent signal pathway in lungs is closely connected with Chlamydia pneumoniae infection. SB203580 treatment can effectively controll the elevation of TLR2 mRNA and p38 MAPK mRNA expressions in lung. It can effectively control the TLR2-MAPK signal transduction pathway.
Myocardial remodeling is one of the important pathological basis when myocardial infarction or pressure overload occurs, whereas mangiferin which is a naturally occurring xanthone has a broad range of therapeutic effect on postinfarction myocardial remodeling. Mangiferin attenuates myocardial infarction by preventing the accumulation of myocardial collagen and the development of intercellular fibrosis. Mangiferin's inhibition to p38 mitogen activated protein kinases plays an important role in the cardioprotective effect. Inhibition of p38 mitogen activated protein kinases significantly decreases TNF-α and then brings the cardioprotective effect. Similarly, p38 mitogen activated protein kinases in pressure overload disease also play a very important role. Understanding of these has direct implications for clinical therapy.
Objective To investigate changes of TLR2 mRNA expression in lung of a mouse model of Chlamydia Pneumoniae pneumonitis, and to explore the possible mechanism of signal transduction. Methods Ninety-six male C3H/HeJ mice were randomly divided into four groups as follows: a control group, a model group, a SB203580 intervened group, and a pyrrolidine dithiocarbamate( PDTC) intervened group. Chlamydia Pneumoniae pneumonitis was induced by intranasally inoculated with 4. 0 ×106 IFU/mL of C. Pneumoniae per mouse in the model group and two intervened groups. Then the intervened groups were intraperitoneally injected with the p38MAPK inhibitor SB203580 and nuclear factor kappa B ( NF-κB)inhibitor PDTC, respectively. Six mice in each group were randomly killed in 1st, 4th, 7th and 14th day. The expressional changes of TLR2 mRNA in the mice lung tissue were measured by semi-quantitative RT-PCR. The concentrations of TNF-α in the lung homogenate were measured by ELISA. Results TLR2 mRNA expression in the lung tissue significantly increased after C. Pneumoniae infection, peaking at 4th and 7th days, then decreased after 14th day. Tumor necrosis factor-α( TNF-α) was also elevated in the lung tissue after C. Pneumoniae challenging. Both SB203580 and PDTC treatment effectively inhibited TNF-αand TLR2 mRNA expressions in lung. The inhibitory effect was more obvious by SB203580 treatment. Conclusion C. Pneumoniae can upregulate the expressions of TLR2 and TNF-α in lung, and TLR2/MAPK and TLR2 /NF-κB signal pathways may be involved in Chlamydia Pneumoniae pneumonitis.
Objective To investigate whether p38 mitogen activated protein kinase (p38MAPK) inhibitor can reduce acute lung injury (ALI) caused by lipopolysaccharide (LPS) by regulating Th17/Treg balance. Methods Balb/c mice were randomly divided into a control group, an ALI group and an intervention group. The mice in the control group were injected with phosphate-buffered saline, the mice in the ALI group were intraperitoneally injected with 40 mg/kg LPS, and the mice in the intervention group were injected with SB203580 (0.5 mg/kg, 1 mg/kg, 2 mg/kg, 5 mg/kg) intraperitoneally 1 h prior to the intraperitoneal injection of LPS. All mice were killed on 12 h later respectively. Hematoxylin-eosinstin staining was used to observe the pathological changes of lung tissue, and cell classification, counting, and total protein levels in bronchoalveolar lavage fluid (BALF) were detected. Transcript expression of forkhead box p3 (Foxp3) and retinoic acid receptor-related orphan receptor-γt (RORγt) was detected by real-time polymerase chain reaction. Interleukin (IL)-6, IL-10, IL-17, IL-23 and transforming growth factor-β (TGF-β) in lung tissue and IL-6, tumor necrosis factor-α (TNF-α) in serum were measured by enzyme-linked immunosorbent assay. The Th17 and Treg subset distribution in spleen was determined by flow cytometry. Results Histopathological examination showed that LPS induced inflammatory cell infiltration in lung tissue, increased cell count and protein levels in BALF (P<0.05), and increased proportion of neutrophils and monocytes in the ALI mice. SB203580 significantly attenuated tissue injury of the lungs in LPS-induced ALI mice. Serum levels of IL-6 and TNF-α in the ALI group were significantly higher than those in the control group, and inflammatory cytokines were decreased after SB203580 intervention. Compared with the ALI group, the production of inflammatory cytokines associate with Th17, including IL-17, IL-23, RORγt was inhibited, and the production of cytokines associate with Treg, such as IL-10 and Foxp3 in lung tissue was increased in the intervention group in a concentration-dependent manner with SB203580. After SB203580 intervention, Th17/Treg ratio was significantly decreased compared with the LPS group (P<0.05). Conclusion p38MAPK inhibitor can reduce LPS-induced ALI by regulating the imbalance of Treg cells and Th17 cells.
ObjectiveTo investigate whether the miR-33s negatively regulates LPS-induced production of inflammatory cytokines by targeting p38 MAPK. MethodsHuman monocytes THP-1 cells were cultured in vitro and transfected with miR-33s mimic (25 nmol/L) or miR-33s inhibitor (25 nmol/L)by TransIT-X2® Dynamic Delivery System for 24 h. Then the transfected THP-1 cells were stimulated by LPS of 10.0 ng/mL for 24 h. The expression of miR-33s and p38 MAPK protein were measured by semi-quantitative RT-PCR. The concentrations of TNF-α,IL-6 and IL-1β in the cultured supernatant were assessed by ELISA. ResultsThe transfection of miR-33s mimic significantly increased the release of TNF-α,IL-6 and IL-1β(P<0.05). The expression of p38 MAPK protein was also significantly reduced(P<0.05). However,the pre-treatment of miR-33s inhibitor reversed the LPS-induced release of TNF-α,IL-6,and IL-1β,and the expression of p38 MAPK protein of THP-1 cells. ConclusionmiR-33s may play an important role in the regulation in inflammatory factors released from THP-1 cells by targeting p38 MAPK.
ObjectiveTo investigate the effects and mechanisms of G protein-coupled receptor 91 (GPR91) on blood-retinal barrier (BRB) in diabetic rats. MethodsA lentiviral vector of shRNA targeting rat GPR91 and scrambled shRNA were constructed. Healthy male Sprague-Dawley (SD) rats were selected in this study. The 60 rats were randomized into 4 groups and treated as follows:(1) control group (Group A, n=15), the rats received injections of an equal volume of 0.1% citrate buffer; (2) streptozocin (STZ) group (Group B, n=15), the rats received injections of STZ; (3) LV.shScrambled group (Group C, n=15), diabetic rats received an intravitreal injection of 1 μl 1×108 TU/ml scrambled shRNA lentiviral particles at 2 weeks after the induction of diabetes; (4) LV.shGPR91 group (Group D, n=15), diabetic rats received an intravitreal injection of 1 μl 1×108 TU/ml pGCSIL-GFP-shGPR91 lentiviral particles. At 12 weeks after intravitreal injection, immunohistochemistry and Western blot were used to assess the expression of GPR91, p-extracellular signal-regulated kinase(ERK)1/2, t-ERK1/2, p-Jun N-terminal kinase (JNK), t-JNK, p-p38 mitogen-activated protein kinase (MAPK) and t-p38 MAPK. Haematoxylin and eosin (HE) staining and Evans blue dye were used to assess the structure and function of the retinal vessel. Immunohistochemistry enzyme-linked immunosorbent assay (ELISA) was used to test the protein level of VEGF. ResultsImmunohistochemistry staining showed that GPR91 was predominantly localized to the cell bodies of the ganglion cell layer. Western blot showed that GPR91 expression in Group D decreased significantly compared with Group C (F=39.31, P < 0.01). HE staining showed that the retina tissue in Group B and C developed telangiectatic vessels in the inner layer of retina, while the telangiectatic vessels attenuated in Group D. It was also demonstrated in Evans blue dye that the microvascular leakage in Group D decreased by (33.8±4.11)% compared with Group C and there was significant difference (F=30.35, P < 0.05). The results of ELISA showed the VEGF secretion of Group B and C increased compared with Group A and the VEGF expression in Group D was significantly down regulated after silencing GPR91 gene (F=253.15, P < 0.05).The results of Western blot indicated that compared with Group A, the expressions of p-ERK1/2, p-JNK and p-p38 MAPK were significantly upregulated (q=6.38, 2.94, 3.45;P < 0.05). Meanwhile, the activation of ERK1/2 was inhibited by GPR91 shRNA and the difference was statistically significant (F=22.50, P < 0.05). ConclusionsThe intravitreal injection of GPR91 shRNA attenuated the leakage of BRB in diabetic rats. GPR91 regulated the VEGF release and the leakage of BRB possibly through the ERK1/2 signaling pathway.