【Abstract】ObjectiveTo explore the effects of p38 mitogenactivated protein kinase (MAPK) on apoptosis of small intestinal epithelial cells after transplantation in rats. MethodsSmall intestinal transplantation was performed in SD and Wistar rats. The recipients were divided into three groups: isograft group (Wistar→Wistar group), allograft group (SD→Wistar group) and allograft+cyclosporine A group (SD→Wistar+CsA group). The grafts were harvested on day 1, 3, 5 and 7 after operation. All graft samples were subjected to histological examination. The apoptosis of graft epithelial cells was detected by TUNEL method. p38 MAPK was measured by Westernblotting method and serum TNFα was determined by ELISA. ResultsMild, moderate and severe rejection reaction occurred in the SD→Wistar group, it was showed that the number of apoptotic cells increased with the severity of the rejection reaction by TUNEL. In SD→Wistar group, the numbers of apoptotic cells were significantly higher than those of the other two groups （P＜0.01）. The severity of rejection reaction in SD→Wistar+CsA group was less than that of SD→Wistar group and the number of apoptotic cells increased with the severity of the rejection reaction (P＜0.01). The level of serum TNFα varied with the apoptotic degree of small intestinal epithelial cells in SD→Wistar group and SD→Wistar+CsA group （P＜0.01）. The expression of p38 MAPK increased with the number of the apoptotic cells in SD→Wistar group and SD→Wistar+CsA group （P＜0.01）, but there was no evident change in Wistar→Wistar group （Pgt;0.05）. The expression of p38 MAPK and the level of serum TNFα were positively correlated with apoptosis in small intestinal rejection after transplantation （r=0.875， P＜0.01； r=0.837， P＜0.01）. p38 MAPK and TNFα were also positively correlated （r=0.826，P＜0.01）. ConclusionApoptosis plays an important role in small intestinal rejection. p38 MAPK is involved in apoptosis and is an important regulator in signal pathway of cell apoptosis.
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.
Objective To investgate the expression of p38 mitogen-activated protein kinase （p38MAPK） in lung tissue of rats with severe acute pancreatitis （SAP）， and to explore the relationship between p38MAPK and pulmonary capillary barrier injury. Methods Forty male and healthy Sprague-Dawley （SD） rats were randomly （random number method） divided into sham operation （SO） group and SAP group， then rats of SAP group were sub-divided into 3， 6， 12， and 24 h group， each group enrolled 8 rats， respectively. SAP model rats were established by injecting 5% sodium taurocholate solution retrograde into the biliopancreatic duct. ELISA method was used to test the serum tumor necrosis factor-α （TNF-α） and interleukin-1β （IL-1β）， and pathological changes in lung and pancreas tissues were observed by HE staining. Immunohischemistry method was used to detect phosphorylated p38 （p-p38） protein and aquaporin 1 （AQP1） protein of lung tissues. The expression level of AQP1 mRNA was measured by quantitative real-time PCR. Results Hyperemia， edema， and inflammatory cell infiltration were observed in lung tissues， abundance of necrosis， part gland structure fuzzy or even disappear were observed in pancreas tissues of all 4 time point groups. Compared with SO group， levels of serum TNF-α and IL-1β were significantly higher in 4 time point groups （P＜0.05）. Lower expression level of p-p38 protein was detected in lung tissues of SO group， while in the early stage of SAP （SAP 3 h group）， the expression level of p-p38 protein significantly increased， which peaked in 6 h group and was still higher than SO group in 24 h group （P＜0.05）. Compared with SO group， the expression levels of AQP1 mRNA and protein were significantly lower in all 4 time point groups （P＜0.05）， which had negative correlation with the levels of serum TNF-α，IL-1β， and the expression level of p-p38 protein （r=-0.87， P＜0.05；r=-0.88， P＜0.05；r=-0.78， P＜0.05）. Conclusion The decrease of AQP1 protein in lung tissue is one of the vital causes for pulmonary capillary barrier injury in SAP， which probably works by the activation of p38MAPK and the excessive release of inflammatory cytokines.
Objective To investigate the effects of glutathione S-transferase M5 (GSTM5) on the inflammation in human bronchial epithelial 16HBE cells and its possible molecular mechanisms. Methods Acute lung injury cell model was constructed with 16HBE cells induced by tumour necrosis factorα (TNF-α, 10 ng/mL). The cells were devided into a control group, a TNF-α group (TNF-α), a GSTM5 group (GSTM5+TNF-α), a negative control group (negative control plasmid+TNF-α). GSTM5-GFP plasmid and negative control plasmid were respectively transfected to the cells of the GSTM5 group and the negative control group using Lipofectamine2000. The contents of interleukin-6(IL-6), IL-8, IL-10 in the cell supernatant were measured by ELISA.The expression of nuclear factor-κB (NF-κB) mRNA was detected by RT-PCR, and the expression of NF-κB, phospho-NF-κB, p38, phospho-p38 protein were detected by Western blot. Results The GSTM5-GFP eukaryotic expression vector was successfully constructed and transfected successfully confirmed by fluorescence microscope. The contents of IL-6, IL-8, IL-10 in the TNF-α-induced cell supernatant were significantly higher than those in the control group(P < 0.05), and the contents of IL-6, IL-8, IL-10 in the GSTM5 group were lower than those in the TNF-α group (P < 0.05)with statistically significant difference. At the same time, the total NF-κB mRNA, phospho -NF-κB and phospho-p38 protein were increased in TNF-α stimulated cells compared with the control group (P < 0.05), while the GSTM5 group was lower than that in the TNF-α group and the negative control group (P < 0.05). Conclusion Overexpression of GSTM5 inhibits the phosphorylation of p38MAPK and NF-κB and down-regulates the inflammation of TNF-α-induced human bronchial epithelial 16HBE cells.
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 the feasibility of selenium-methylselenocysteine (SMC) to promote peripheral nerve regeneration and its mechanism of action. Methods Rat Schwann cells RSC96 cells were randomly divided into 5 groups, which were group A (without any treatment, control group), group B (adding 100 μmol/L H2O2), group C (adding 100 μmol/L H2O2+100 μmol/L SMC), group D (adding 100 μmol/L H2O2+200 μmol/L SMC), group E (adding 100 μmol/L H2O2+400 μmol/L SMC); the effect of SMC on cell proliferation was detected by MTT method, and the level of oxidative stress was detected by immunofluorescence for free radicals [reactive oxygen species (ROS)] after determining the appropriate dose group. Thirty-six 4-week-old male Sprague Dawley rats were randomly divided into 3 groups, namely, the sham operation group (Sham group), the sciatic nerve injury group (PNI group), and the SMC treatment group (SMC group), with 12 rats in each group; the rats in the PNI group were fed with food and water normally after modelling operation, and the rats in the SMC group were added 0.75 mg/kg SMC to the drinking water every day. At 4 weeks after operation, the sciatic nerves of rats in each group were sampled for neuroelectrophysiological detection of highest potential of compound muscle action potential (CMAP). The levels of inflammatory factors [interleukin 17 (IL-17), IL-6, IL-10 and oxidative stress factors catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA)] were detected by ELISA assay. The luxol fast blue (LFB) staining was used to observe the myelin density, fluorescence intensity of glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) was observed by immunofluorescence staining, and myelin morphology was observed by transmission electron microscopy with measurement of axon diameter. Western blot was used to detect the protein expressions of p38 mitogen-activated protein kinases (p38MAPK), phosphorylated p38MAPK (p-p38MAPK), heme oxygenase 1 (HO-1), and nuclear factor erythroid 2-related factor 2 (Nrf2). ResultsMTT assay showed that the addition of SMC significantly promoted the proliferation of RSC96 cells, and the low concentration could achieve an effective effect, so the treatment method of group C was selected for the subsequent experiments; ROS immunofluorescence test showed that group B showed a significant increase in the intensity of ROS fluorescence compared with that of group A, and group C showed a significant decrease in the intensity of ROS fluorescence compared with that of group B (P<0.05). Neuroelectrophysiological tests showed that the highest potential of CMAP in SMC group was significantly higher than that in PNI and Sham groups (P<0.05). ELISA assay showed that the levels of IL-6, IL-17, and MDA in PNI group were significantly higher than those in Sham group, and the levels of IL-10, SOD, and CAT were significantly lower; the levels of IL-6, IL-17, and MDA in SMC group were significantly lower than those in PNI group, and the levels of IL-10, SOD, and CAT were significantly higher (P<0.05). LFB staining and transmission electron microscopy showed that the myelin density and the diameter of axons in the SMC group were significantly higher than those of the PNI group and the Sham group (P<0.05). Immunofluorescence staining showed that the fluorescence intensity of GFAP and MBP in the SMC group were significantly stronger than those in the PNI group and Sham group (P<0.05). Western blot showed that the relative expressions of Nrf2 and HO-1 proteins in the SMC group were significantly higher than those in the PNI group and Sham group, and the ratio of p-p38MAPK/p38MAPK proteins was significantly higher in the PNI group than that in the SMC group and Sham group (P<0.05). Conclusion SMC may inhibit oxidative stress and inflammation after nerve injury by up-regulating the Nrf2/HO-1 pathway, and then inhibit the phosphorylation of p38MAPK pathway to promote the proliferation of Schwann cells, which ultimately promotes the formation of myelin sheaths and accelerates the regeneration of peripheral nerves.