Effect of Panax notoginoside on pulmonary arterial pressure and expression of p38 MAPK in lung tissues of hypoxic rats

AIM: To observe the effect of Panax notoginoside (PNS) on the pulmonary artery pressure and the p38 mitogen-activated protein kinase(p38 MAPK) in lung tissues of rats treated with hypoxia. METHODS: Thirty adult male SD rats were randomly divided into 3 groups. The rats in normal control group were exposed to normal conditions, the rats in hypoxia group were exposed to isobaric hypoxia, and the rats in hypoxia+PNS group were treated with PNS under the condition of hypoxia. After 4 weeks of treatment, the mean pulmonary arterial pressure (mPAP) and the mean carotid arterial pressure (mCAP) were measured by cardiac catheterization. The heart was isolated, and the right ventricle (RV), left ventricle plus ventricular septum (LV+S) were weighed to calculate the ratio of RV/(LV+S).The quantity of phospho-p38 MAPK(p-p38 MAPK) in rat pulmonary arterioles was determined by the method of immunohistochemistry and the mRNA content of p38 MAPK was tested by RT-PCR. RESULTS: The mPAP and RV/(LV+S) in hypoxia group were higher than those in normal control group. The expression of p-p38 MAPK in rat pulmonary arterioles and p38 MAPK mRNA in the lung tissues were higher than those in normal control group (P<0.05). The mPAP, RV/(LV+S), the expression of p-p38 MAPK in rat pulmonary arterioles and p38 MAPK mRNA in the lung tissues in hypoxia+PNS group were significantly lower than those in hypoxia group (P<0.05).CONCLUSION: PNS possesses the preventive and therapeutic effect on hypoxic pulmonary hypertension by decreasing p-p38 MAPK and down-regulation of p38 MAPK mRNA in the lungs.     

GSH deletion increases the activity of p38MAPK in MNNG treatment

AIM: To explore the effect of low concentration of N-methyl-N-nitro-N-nitroguanidine (MNNG) on p38MAPK, and the function of glutathione (GSH) on p38MAPK. METHODS: Western blotting was applied to detect the p38MAPK phosphorylation in MNNG treatment group and control group. To study the effect of GSH on MNNG-regulated p38MAPK activity, the intracellular GSH level was reduced by pretreatment of L-buthionine-S, R-sulfoximine (BSO). Assuming the absorbance of band in control group as 1.0, the relative P/T values of the treatment groups were calculated, with the “P” served as absorbance values of phospho-p38MAPK and the “T” as absorbance values of total p38MAPK. RESULTS: In BSO pretreated groups，the relative P/T in samples treated with MNNG for 2.5 h was 0.84, and became 2.19 with 3 h more incubation in the fresh medium. CONCLUSION: GSH deletion increases the activity of p38MAPK in MNNG treatment.     

Age-associated changes of p38 MAPK and JNK signal pathways in cardiac fibroblasts treated with transforming growth factor beta 1

AIM:To investigate the effect of aging on p38 mitogen-activated protein kinase(MAPK) and c-Jun N-terminal kinase(JNK) signal pathways in rat cardiac fibroblasts(CFs). METHODS:Cardiac fibroblasts obtained from neonatal and aged rats were cultured and randomly divided into 4 groups:neonatal PBS control group(N1 group), neonatal TGF-β₁ treatment group(N2 group), aged PBS control group(A1 group) and aged TGF-β₁ treatment group(A2 group). Proliferation of CFs was detected by MTT coloricmetric assay. The expression levels of total p38 MAPK, JNK, phospho-p38 and phospho-JNK were measured by Western blotting. RESULTS:The proliferative capacity of aged CFs was significantly decreased as compared with neonatal CFs after stimulated with TGF-β₁. In response to TGF-β₁, the expression levels of phospho-p38 and phospho-JNK were significantly increased in N2 group and A2 group as compared with N1 group and A1 group, respectively. The levels of total p38 and nonphosphorylated JNK in N2 group were similar to those in A2 group. Compared with N2 group, the levels of phospho-p38 and phospho-JNK markedly decreased in A2 group. CONCLUSION:These data indicate that p38 MAPK and JNK signal pathways are impaired in aged CFs.     

Association among COX2, iNOS and p38MAPK in late phase of preconditioning in rat cardiomyocytes

AIM:To explore the association among COX₂ , iNOS and p38MAPK in late phase of preconditioning. METHODS: The expression of COX₂ , iNOS and p38MAPK activity were determined by western blotting and the injury of cardiomyocyte was assessed by LDH release and trypan blue exclusion in four groups: control group, group IPC (ischemic preconditioning), group SMT (iNOS inhibitor), group NS₃₉₈ (COX₂ inhibitor) and group SB (p38MAPK inhibitor).RESULTS:The expression of COX₂ in group IPC increased markedly in comparision with group SMT and group SB.The expression of iNOS in group SB was lower than that in group IPC and group NS₃₉₈.The difference of the amount of iNOS was not significant between group IPC and group NS₃₉₈.The difference of the amount of phospho-p38MAPK was not significant among group IPC, group SMT and group NS₃₉₈(P>0.05).The LDH was lower, and cell viability was higher in group IPC than those in control group.The LDH was higher, and cell viability was lower in group SMT, group NS₃₉₈ and group SB than those in group IPC. CONCLUSIONS:In late phase of preconditioning , the p38MAPK activity and expression of iNOS and COX₂ increase significantly in rat cardiomyocytes, activited p38MAPK mediates iNOS, then promotes COX₂ expression.     

Role of p38 MAPK signaling pathway in inflammatory effects on cerulein-induced pancreatic cells

AIM: To investigate the effect of p38 MAPK signal pathway on cerulein-treated pancreatic acinar AR42J cells.METHODS: AR42J cells were divided into control group, cerulein group (treated with 10^-8 mol/L of cerulein), and SB203580 group (treated with 10 μmol/L of SB203580 and 10^-8mol/L of cerulein).The cells were harvested 3 h after treatment.Secretion rate of amylase was measured.The translocation of p-p38 MAPK to nuclei was imaged by immunofluorescence.The protein expression levels of p-p38 MAPK and TNF-α were detected by Western blotting.The activation of NF-κB was measured by electrophoretic mobility assay.RESULTS: Compared with control group, cerulein resulted in increases in the secretion rate of amylase and protein level of TNF-α (P<0.01), as well as the expression levels of p-p38 MAPK and NF-κB (P<0.01).Cerulein induced nuclear translocation of p-p38 MAPK.Compared with cerulein group, the secretion rate of amylase and protein level of TNF-α in SB203580 group decreased significantly (P<0.01).The expression of p-p38 MAPK and NF-κB also decreased greatly (P<0.05).Nuclear translocation of p-p38 MAPK was inhibited by SB203580.CONCLUSION: The p38 MAPK pathway involves in cerulein-induced pancreatic inflammatory response via regulating NF-κB.     

Protective effects and mechanism of astragalus injection on asthmatic rats

AIM: To explore the protective effects and mechanism of astragalus injection on asthmatic rats.METHODS: OVA was injected intraperitoneally and inhaled to produce the asthmatic model.Forty rats were randomly divided into five groups: control group,asthma group and astragalus groups of high,medium and low dose.The concentrations of IL-4,IFN-γ in BALF,the expression of IL-4 mRNA,IFN-γ mRNA and phospho-p38 MAPK in lung tissues were respectively measured by ELISA,RT-PCR and Western blotting.The number of inflammatory cells in BALF and histropathology changes were observed.RESULTS: In asthmatic group,the number of inflammatory cells and the concentrations of IL-4 in BALF and the expression of IL-4 mRNA,phospho-p38 MAPK in lung tissue were higher,but IFN-γ and IFN-γ mRNA were lower than those in normal control rats (P<0.01).In astragalus group,the number of inflammatory cells,the concentrations of IL-4 in BALF and the expression of IL-4 mRNA,phospho-p38 MAPK in lung tissue were lower,but IFN-γ and IFN-γ mRNA were higher than those in normal control rats (P<0.01),and histropathology damage was alleviated significantly.The efficacies in the astragalus groups of high,medium and low dose were similar,which no significant difference was observed among them.There were positive correlations between the expression of 〖JP3〗phospho-p38 MAPK and the number of eosinophil,the concentration of IL-4,IL-4 mRNA (r=0.63,r=0.69,r=0.71,〖JP〗 P<0.01),and negative correlations between the expression of phospho-p38 MAPK and IFN-γ and IFN-γ mRNA (r=-0.65,r=-0.68,P<0.01).CONCLUSION: p38 MAPK may play a role in pathological process of asthma.Astragalus effectively treats asthma by inhibiting the expression of phospho-p38 MAPK,correcting the inbalance of IFN-γ/ IL-4 and decreasing the number of inflammatory cells.     

TPX2 induces apoptosis of rectal cancer HR-8348 cells through p38 MAPK signaling pathway

AIM: To study the effect of targeting protein for Xenopus kinesin-like protein 2 (TPX2) expression knockdown on the apoptosis of rectal cancer HR-8348 cells.METHODS: The HR-8348 cells transfected with TPX2 small interfering RNA (siRNA) served as TPX2 siRNA group. The non-transfected cells were used as control group. The cells transfected with siRNA negative control (siRNA-NC) were used as siRNA-NC group. The TPX2 siRNA-transfected cells exposed to p38 MAPK inhibitor SB203580 served as TPX2 siRNA+SB203580 group. The expression of TPX2 at mRNA and protein levels was determined by RT-qPCR and Western blot. The cell viability was measured by MTT assay, the apoptosis was analyzed by flow cytometry. The protein levels of p38 MAPK, p-p38 MAPK, cleaved caspase-3 and Bcl-2 in the HR-8348 cells were determined by Western blot.RESULTS: After transfection, the expression of TPX2 at mRNA and protein levels was decreased in TPX2 siRNA-transfected cells (P<0.05). Transfection with siRNA-NC had no effect on TPX2 mRNA and protein levels in the cells. After knockdown of TPX2 expression, the viability of rectal cancer HR-8348 cells and the expression of Bcl-2 were decreased, while the apoptotic rate and the protein levels of cleaved caspase-3 and p-p38 MAPK/p38 MAPK were increased significantly reduced (P<0.05). Compared with TPX2 siRNA group, the apopto-tic rate and the protein levels of cleaved caspase-3 and p-p38 MAPK/p38 MAPK in TPX2 siRNA+SB203580 group were significantly decreased, while the viability was significantly increased (P<0.05).CONCLUSION: Knockdown of TPX2 expression promotes apoptosis of rectal cancer HR-8348 cells by activating p38 MAPK signaling pathway.     

Role of p38 MAPK in cyclic mechanical stretch induced HMGB1 expression in alveolar macrophages

AIM: To investigate the role of p38 mitogen-activated protein kinase (MAPK) in cyclic mechanical stretch induced the expression of high mobility group box 1 protein (HMGB1) in alveolar macrophages (AMs). METHODS: AMs were cultured and seeded at 1×108 cells/L in 6-well Bioflex cell culture plates. Subsequently, the cells were exposed to cyclic mechanical stretch at 20% (group B) elongation using Flexercell 4000T cell stretching unit. In group C, cells were pre-treated with SB203580 (40 μmol/L) for 2 h before mechanical stretch. Group A served as control. The expression of HMGB1 mRNA in alveolar macrophages was detected by RT-PCR. p38 MAPK activity and the expression of HMGB1 protein were measured by Western blotting analysis. RESULTS: The expression of HMGB1 mRNA and protein, and the activity of p38 MAPK in AMs were significantly increased in group B than those in group A (P<0.05). SB203580, an inhibitor of p38 MAPK, significantly inhibited the inducing effect of mechanical stretch (P<0.05). CONCLUSION: Mechanical stretch regulates the expression of HMGB1 mRNA and protein in alveolar macrophages by activating p38 MAPK signal pathway.     

Expression and functional role of p38 MAPK in the kidney after unilateral ureteral obstruction in rats

AIM: To investigate the expression and functional role of p38MAPK in the kidney after unilateral ureteral obstruction in rats. METHODS: Unilateral ureteral obstruction (UUO) models were induced by ligating the left ureter. Rats were sacrificed at 1 h, 3 h, 6 h, 12 h, 1, 3, 5, 7, 14, 21, and 28 days after UUO was initiated. p38MAPK activity was assayed by immunohistochemical staining and specific substrate phosphorylation with immunoprecipitation and Western blotting. TGFβ mRNA and protein expression were analyzed with in situ hybridization and immunohistochemical stainning. RESULTS: A basic p38MAPK activity was detectable in the normal kidney(0.22±0.06).p38MAPK pathway was rapidly act ivated at 1 hour(0.45±0.14 vs control,P<0.05)and this was steadily in creased by 12 hours(0.91±0.07 vs control,P<0.01)after UUO.Afterwards,the activity of p38MAPK reduced grad ually,then increased again from 3 days and this was steadily increased by 7 days(0.93±0.06 vs control,P<0.01). Upregulation of TGFβ₁ was markedly tested at 3 days(13.55±6.33 vs control,P<0.05)and this was steadily in creased by 7 days(26.78 8.77 vs control,P<0.01).The activation of p38MAPK preceded markedly the expression of TGF 1.The early activity of p38 MAPK was positively related to the amount of TGFβ₁ expression.The amount of TGFβ₁ expressed in obstructed kidney also related significant ly to the late activity of p38MAPK(r=0.84,P<0.01). CONCLUSION: The activity of p38MAPK is increased significantly in the obstructed kidney, which may cause renal fibrosis via inducing the expression of TGFβ₁.     

Effects of Jiedu-Qingfei mixture on NF-κB and p38 MAPK pathways in lung tissues of rats with Mycoplasma pneumoniae infection

AIM: To observe the therapeutic effect of Jiedu-Qingfei mixture on Mycoplasma pneumoniae (MP)-infected rat lung tissues and to explore its mechanism. METHODS: SD rats (n=40) were randomly divided into 4 groups:blank control group, model group, Jiedu-Qingfei group and positive control group, with 10 rats in each group. The rats in experimental groups were slowly dripped with 1×10⁹ CFU/L MP solution into their nostrils for 4 d. One rat in each group was sacrificed for MP nucleic acid detection at the second day after inoculation, and the other rats were given gavage therapy. The rats in blank control group and model group were intragastrically given the same volume of normal saline, the rats in Jiedu-Qingfei group were given 8 mL/kg Jiedu-Qingfei mixture daily for 4 weeks, and the rats in psoitive control group were given dexmethasone sodium phosphate (0.5 mg·kg^-1·d^-1). After the experiment, the rats were killed. The serum and bronchoalveolar lavage fluid (BALF) were collected for detecting the levels of interleukin-12 (IL-12), IL-13 and TNF-α by ELISA. The right lung tissues were used for pathological observation and HE staining, while the left lung tissues were used to detect the expression of NF-κB p50, I-κBα and p38 mitogen-activated protein kinase (p38 MAPK) at mRNA and protein levels. RESULTS: The results of MP nucleic acid detection showed that all the rats except blank control group were MP nucleic acid positive, indicating that the rat model of MP infection was successfully established. On the 1st day of the treatment, the pathological scores of the lung tissues in model group and Jiedu-Qingfei group were significantly higher than those in blank control group (P<0.05). After treatment, the pathological scores of the lung tissues in mo-del group were significantly higher than those in blank control group and Jiedu-Qingfei group. The levels of IL-12 in the serum and BALF in model group were significantly lower than those in blank control group after MP infection (P<0.05), while those after treatment with Jiedu-Qingfei mixture were significantly higher than those in model group (P<0.05). The levels of IL-13 and TNF-α in the serum and BALF of MP-infected rats were increased significantly, while those after treatment with Jiedu-Qingfei mixture were significantly lower than those in model group (P<0.05). The mRNA expression levels of NF-κB p50 and p38 MAPK in model group were increased significantly (P<0.01). After treatment, the mRNA expression levels of NF-κB p50 and p38 MAPK were decreased significantly compared with model group (P<0.01). The mRNA expression level of I-κBα in model group was significantly lower than that in control group. After treatment, the mRNA expression of I-κBα in Jiedu-Qingfei group was significantly higher than that in model group (P<0.05). The protein levels of NF-κB p50 and p38 MAPK in the lung tissues of model group were significantly higher than those of blank control group. After treatment, the protein expression of NF-κB p50 and p38 MAPK was decreased significantly. The protein level of I-κBα in model group was significantly lower than that in blank control group, and after treatment with Jiedu-Qingfei mixture, the protein expression level of I-κBα was increased significantly (P<0.05). CONCLUSION: Jiedu-Qingfei mixture may attenuate lung tissue inflammation caused by MP through NF-κB and p38 MAPK pathways.     

Propofol inhibits activation of p38 MAPK in rat brain tissues with LPS-induced brain injury

AIM: To investigate the effects of propofol on lipopolysaccharide (LPS)-induced activation of p38 mitogen-activated protein kinase (p38 MAPK) and inducible nitric oxide synthase (iNOS) in brain tissues of rats. METHODS: Sprague-Dawley rats of both sexes were randomly divided into 3 groups (n=24 each): control group, LPS group and LPS+propofol group. The models of LPS-induced brain injury were established by injecting LPS (1 mg/kg) via left internal carotid artery in LPS group. Propofol (100 mg/kg) was given intraperitoneally immediately after the LPS was given in LPS+propofol group. The same volume of normal saline was given to the rats in control group. The rats were decapitated 6 h, 24 h, 48 h and 72 h after administration. The brains were immediately isolated to detect the water content, activation of p38 MAPK and the exepression of iNOS protein. Meanwhile, the pathological changes were observed under light microscope. RESULTS: The water content of the brain was higher in LPS group than that in control group. The protein levels of phosphorylated p38 MAPK(p-p38 MAPK) and iNOS in LPS group increased 6 h after LPS administration, reached the peak at 24 h, and still higher than those in control group at 48 h and 72 h (P<0.05). The levels of those indexes were all lower in LPS+propofol group at various time points than those in corresponding LPS group (P<0.05). The pathological changes were slighter than those in LPS group. The water content of the brain was positively correlated with the levels of p-p38 MAPK and iNOS (r=0.603, r=0.727,P<0.05). CONCLUSION: Propofol attenuates LPS-induced brain injury by inhibiting the activation of p38 MAPK and down-regulating iNOS expression.     

Role of p38MAPK activation in high glucose-induced collagen Ⅲ synthesis in normal rat kidney tubular epithelial cells NRK52E

AIM: To study the role of p38 mitogen-activated protein kinase (p38MAPK) activation in high glucose-induced collagen Ⅲ synthesis in NRK52E cells. METHODS: Normal rat tubular epithelial cell line NRK52E was cultured in D-glucose of different concentrations, pretreated with SB203580 and collected at different time points. The levels of phospho-p38MAPK and extracellular matrix collagen Ⅲ were examined by Western blotting. RESULTS: The activation of p38MAPK was shown to be dependent upon D-glucose concentration and the time-course. Pretreatment with SB203580 blocked p38MAPK activation induced by high concentration of D-glucose in NRK52E cells. CONCLUSIONS: The activation of p38MAPK induced by high concentration of glucose may play a role in diabetic interstital renal fibrosis. SB203580 has a potential value of clinical applications in the prevention and treatment of diabetic nephropathy.     

Effect of p38 MAPK on cisplatin-induced renal tubular cell apoptosis

AIM:To investigate the role of p38 MAPK in cisplatin-induced rat renal proximal tubular cell (RPTC) apoptosis. METHODS:To determine the optimal concentration of cisplatin to induce RPTC apoptosis, the cells were treated with 0, 5, 10 and 20 μmol/L cisplatin for 24 h, and then the cell lysates were collected for Western blot analysis of cleaved PARP, p38 and phosphor ylated p38 (p-p38). To determine the role of p38 MAPK in cisplatin-induced RPTC apoptosis, the cells were divided into control group, cisplatin group (the cells were treated with cisplatin for 24 h) and cisplatin+p38 MAPK inhibitor group (the cells were treated with p38 MAPK inhibitor SB203580 for 1 h, and then treated with cisplatin for another 24 h). The morphological changes of apoptotic cells were observed under phase-contrast fluorescence microscope. The apoptotic rate of the cells were analyzed by flow cytometry. The caspase activity of RPTC lysates was examined using Ac-DEVD-AFC kit. The protein levels of p-p38, p38, cleaved PARP and cleaved caspase-3 were determined by Western blot. The pH value of extracellular environment of the cells was measured by pH meter. RESULTS:Cisplatin at 20 μmol/L obviously induced apoptosis of RPTC. The p38 MAPK was phosphorylated and its phosphorylation peaked at 15 min after cisplatin treatment. The apoptotic rate of RPTC was 12.08% after cisplatin induction. Cisplatin treatment also enhanced caspase activity, and increased cleavage of PARP and caspase-3 proteins (P<0.05). The p38 MAPK inhibitor SB203580 effectively inhibited the phosphorylation of p38 MAPK, down-regulated the RPTC apoptosis rate and caspase activity, and reduced the cleavage of PARP and caspase-3 proteins. The pH value change in RPTC culture medium was also inverted by SB203580. CONCLUSION:The phosphorylation of p38 MAPK is involved in cisplatin-induced apoptosis of RPTC. The apoptosis induced by cisplatin results in the change of acidic extracellular environment, which is inhibited by p38 MAPK inhibitor SB203580.     

High glucose induces down-regulation of BMP-7 expression in renal tubular epithelial cells through p38 MAPK pathway

AIM: To observe the BMP-7 expression in primary renal tubular epithelial cells cultured with high glucose and to investigate the role of p38MAPK signaling pathway.METHODS: The primary renal tubular epithelial cells were randomly treated with normal glucose, high glucose, co-incubation of high glucose with specific p38MAPK inhibitor SB202190 or D-mannitol for 72 h. The protein expression of BMP-7 and fibronectin (FN) in all the cells was assessed by the method of immunocytochemistry. The protein expression of p38MAPK and p-p38MAPK was determined by Western blotting. The mRNA expression of BMP-7 and FN was detected by RT-PCR.RESULTS: In normal glucose group, BMP-7 was highly expressed in the cytoplasm of tubular epithelial cells, and only small amounts of p38MAPK and FN, but not p-p38MAPK, were observed. High glucose was able to activate p38MAPK, and therefore the protein of p-p38MAPK increased remarkably in high glucose-treated cells. High glucose also enhanced FN production. Meanwhile, the expression of BMP-7 decreased. Co-incubation of high glucose with SB202190 for 72 h reduced the activity of p38MAPK by 80% and the FN expression was also decreased, while the BMP-7 expression significantly increased. No significant difference of the BMP-7 or FN expression between control group and D-mannitol group was observed.CONCLUSION: The expression of BMP-7 at mRNA and protein levels in renal tubular epithelial cells is decreased under the condition of high-glucose cultivation. Suppression of p38MAPK signaling pathway stimulates endogenous BMP-7 expression, indicating that p38MAPK pathway may be involved in the down-regulation of BMP-7 in renal tubular epithelial cells by high glucose.     

Preventive effect of viartrils on the cartilage degenration of osteoarthritis in rabbits

AIM: To determine whether the viartrils could provide a beneficial effect on the prevention of early/middle stage osteoarthritis(OA) and affect the proliferation of chondrocytes. METHODS: An OA model was produced with severing the anterior, posterior cruciate ligaments of the knee in 24 adult New Zealand rabbits. The animals were then randomly divided into viartrils group and control group. After surgical operation, viartrils (mainly contains glucosamine sulphate) 2 pills per day were administered to the animals in viartrils group. The animals were sacrificed and specimens were taken from the weight-bearing portion of the femoral condylar seven weeks after operation. Each case was evaluated according to a modified histological-histochemical grading system(HHGS) using HE and safranin O/fast green staining slides, and immunohistochemical method was used to detect the proliferation of chondrocytes in articular cartilage. RESULTS: The method of severing the anerior, posterior cruciate ligaments of the knee could successfully induce the early/middle stage model of OA. The pathological remark in control group was significantly higher than that in the viartrils group (P<0.05). The proliferative index of viartrils group chondrocytes was also higher than that in control (P<0.05). CONCLUSION: These data indicate that viartrils could increase the proliferation of chondrocytes and prevent the development of OA pathologic process.     

Effect of glucocorticoid on PI-3K and p38 MAPK signaling pathways in 3T3-L1 adipocytes

AIM: To study the effects of dexamethasone (DEX) on the glucose transport system and the PI-3K/Akt and p38 MAPK insulin signaling pathways in 3T3-L1 adipocytes,and to investigate the possible mechanism in glucocorticoid induced insulin resistance. METHODS: The 3T3-L1 adipocytes were exposed to DEX for 48 h and incubated with 100 nmol/L insulin for additional 30 min. The glucose uptake was measured by detecting the glucose content in cell culture supernatants. Then expression and distribution of Glut4 was measured. The insulin signaling proteins Akt,phospho-Akt,p38MAPK and phospho-p38MAPK were also measured with Western blotting. RESULTS: DEX inhibited insulin stimulated glucose transport capacity in 3T3-L1 adipocytes. DEX did not alter the amount of Glut4 protein in total cell lysates but attenuated the insulin-stimulated Glut4 translocation to the plasma membrane. DEX significantly inhibited insulin stimulated phosphorylation of Akt and p38 MAPK. CONCLUSION: These results suggest that DEX alters insulin stimulated glucose transport capacity in 3T3-L1 adipocytes,which is mediated by attenuating insulin stimulated activation of PI3K-Akt and p38 MAPK pathways,and reducing insulin stimulated Glut4 translocation and transport activity. These may lead to insulin resistance in 3T3-L1 adipocytes.     

Inhibitory effect of notoginsenoside monomer R1 on activation of p38 MAPK signaling pathway induced by hypoxic hypercapnia in PASMCs

AIM: To explore the mechanism of notoginsenoside monomer R₁ (R₁) against hypoxic hypercapnia-induced pulmonary vasoconstriction (HHPV) by investigating the effect of R₁ on p38 mitogen-activated protein kinase (p38MAPK) signaling pathway in pulmonary arterial smooth muscle cells (PASMCs) under the condition of hypoxia and hypercapnia. METHODS: Primary cultured PASMCs, which were isolated from Sprague-Dawley rats, were incubated in logarithmic growth phase from the 2nd to 5th generation with different concentrations (8, 40 and 100 mg/L) of R₁ under the condition of 6% CO₂ plus 1% O₂ for 24 h. The expression of p38 at mRNA and protein levels was detected by RT-PCR and Western blotting,respectively. RESULTS: The results of Western blotting and RT-PCR analysis indicated that the protein and mRNA expression levels of p-p38 MAPK were significantly higher in hypoxic hypercapnia group with DMSO control than those in normoxia control group (P<0.01). In R₁ treatment groups, the levels of p-p38 MAPK protein and p38 MAPK mRNA were markedly decreased (P<0.01) in a dose-dependent manner. CONCLUSION: p38 MAPK signaling pathway may mediate hypoxic hypercapnia pulmonary vasoconstriction in rats. Notoginsenoside monomer R₁ attenuates HHPV, which may be related to blockage of p38 MAPK signal pathway.     

Alteration of p38 MAPK activity in lung tissue in diabetic rats

AIM: To observe the pathologic changes in lung and the role of p38 MAPKinase signal pathways in pulmonary alteration in diabetic rats. METHODS: Diabetic rats were induced by intraperitoneally injected streptozotozin (STZ). After 4 weeks, we observed the pathologic changes in lungs, tested protein kinase C (PKC) activities by isotope in lungs of model rats, tested transforming growth factor (TGF-β₁) by Western blotting and immunohistochemical analysis, and determined the expression of p38 MAPKinase mRNA using in situ hybridization.RESULTS: After STZ administration for 4 weeks, we observed thickened pulmonary capillary basal lamina and increased number of fibre in Diabetes mellitus (DM) rats. TGF-β₁ levels, PKC and p38 MAPK activities were also found increased. CONCLUSION: The increased activities of TGF-β₁ and p38 MAPK suggeste that TGF-β₁ may play an important role in diabetic lung, and hyperglycemia-PKC-p38 MAPK signal pathways may be involved in the pathogenesis of diabetes.