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 observe the protein expression of phosphorylated form of P38 mitogen-activated protein kinase(P38MAPK) and c-Jun in hypertrophic scar skin and to explore their influences on the formation and maturation of hypertrophic scar. METHODS: The expression intensity and distribution of phosphorylated form of P38MAPK and c-Jun were examined with immunohistochemistry and pathological methods in 16 cases of hypertrophic scar skin and 8 cases of normal skin. RESULTS: In normal skin, the positive signals of phosphorylated form of P38MAPK mostly distributed in basal lamina cells of epidermis, while c-Jun was mainly located in epidermal cells and endothelial cells. The positive cellular rates of two proteins were 21.3% +/- 3.6% and 33.4% +/- 3.5% respectively. In proliferative hypertrophic scar skin, the particles of phosphorylated P38MAPK and c-Jun were mainly located in epidermal cells and some fibroblasts. The positive cellular rates of two proteins were significantly elevated to 69.5% +/- 3.3% and 59.6% +/- 4.3% respectively (P lt; 0.01). In mature hypertrophic scar, the expression of these proteins decreased but was still higher than that of normal skin. CONCLUSION: The formation and maturation of hypertrophic scar might be associated with the alteration of phosphorylated P38MAPK and c-Jun protein expression in hypertrophic scar.
Objective To investigate the protective effect of blocking the signal path of p38 mitogen activated protein kinase on blood retinal barrier (BRB) and retinal ganglion cells (RGC) in early diabetic rats.Methods A total of 60 Wistar rats were divided into the control and diabetes group, with 30 rats in each group. Diabetes was induced in rats in diabetes group by peritoneal injection of streptozotocin (STZ);the plasma glucose level of ＞16.7 mmol/L indicated that the diabetes model was set up successfully.The rats in the control group underwent peritoneal injection of equivalent sodium citrate solution. IgG leakage method was used to measure the damage of BRB function and vascular leakage. The expression and localization of caspase-3 and vascular endothelial growth factor (VEGF) in retina of diabetic rats were examined by immunohistochemistry analyses.Two weeks after the establishment of the diabtes model, the rats in diabtes group underwent intravitreal injection with SB203580, a p38 inhibitor;six weeks after the injection, the expression of caspase-3 and VEGF was detected, and the number of apoptosis RGC was counted via immunofluorescence technique.Results In the contral group, IgG staining located in the blood vessels with little leakage; while the IgG leakage was much more obvious in the diabetes group eight weeks after the establishment of the model. Six weeks after intravitreal injection with SB203580, the leakage decreased in diabtes rats. The results of semiquantitative analysis and fluorescence immunohistochemistry showed that compared with the results in diabetes rats 8 weeks after intravitreal injection (2.9 times much more than that in the control group), the fluorescence expression of VEGF decreased in diabetes rats six weeks after intravitreal injection (1.8 times much more than that in the control group).The apoptisis RGC number in rats 6 weeks after intravitreal injection of SB203580 was much less than that in rats without intravitreal injection (t＝5.731, Plt;0.01). Conclusions SB203580 can alleviate the disruption of BRB and apoptosis of RGC in early diabetes rats, which suggests that p38 MAPK pathways appear to be directly involved in the pathogenesis of early diabetic retinopathy.
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 study the effect and mechanism of recombinant human brain natriuretic peptide (rh-BNP) in alleviating myocardial ischemia-reperfusion (I/R) injury by regulating mitogen activated protein kinase (MAPK) pathway. Methods A total of 128 adult male Sprague-Dawley (SD) rats with specific pathogen free were selected. The SD rats were divided into groups according to random number table, including, sham operation (Sham) group, I/R group, I/R+rh-BNP group, negative control adenovirus (Ad-NC)+Sham group, Ad-NC+I/R group, Ad-NC+I/R+rh-BNP group, p38 mitogen-activated protein kinase adenovirus (Ad-p38MAPK)+I/R group and Ad-p38MAPK+I/R+rh-BNP group, with 16 SD rats in each group. Myocardial I/R injury model was established by ligation of left anterior descending coronary artery. Before modeling, rh-BNP was injected intraperitoneally or adenovirus was injected into myocardium; 180 minutes after reperfusion, the contents of lactate dehydrogenase (LDH), creatine kinase isoenzyme (CK-MB) in serum, myocardial infarction size, the contents of reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α) and the expression of phosphorylated p38MAPK (p-p38MAPK), phosphorylated JNK (p-JNK) and phosphorylated extracellular regulated protein kinases 1/2 (p-ERK1/2) were detected. Results The contents of LDH, CK-MB, myocardial infarction size, the contents of TNF-α, ROS and the expression of p-p38MAPK and p-JNK in I/R group were higher than those in Sham group, p-ERK1/2 expression level was lower than that in Sham group (P<0.05). The contents of LDH, CK-MB, myocardial infarction size, the contents of TNF-α, ROS and the expression of p-p38MAPK in I/R+rh-BNP group were lower than those in I/R group (P<0.05), the expression of p-JNK and p-ERK1/2 had no significant difference compared with I/R group (P>0.05). The contents of LDH, CK-MB, myocardial infarction size, the contents of TNF-α, ROS and the expression of p-p38MAPK in Ad-p38mapk+I/R+rh-BNP group were higher than those in Ad-NC+I/R-rh-BNP group (P<0.05). Conclusion rh-BNP can alleviate myocardial I/R injury, which is related to inhibiting p38MAPK pathway, reducing inflammation response and oxidative stress response.