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.
Objective To investigate the efficacy of phloretin combined with sodium hyaluronate in preventing postoperative abdominal adhesion formation in rats and its possible mechanisms. Methods Forty rats were randomly divided into five groups, the rats in the sham-operatinon group only underwent open and closed abdominal surgery, and the remaining rats of four groups underwent cecum scratch-and-rub method of modeling to receive different treatments: the rats in the control group and the phloretin group (PHL group) were closed abdominally after modeling, while the rats in the sodium hyaluronate group (HA group) and the phloretin combined with sodium hyaluronate group (PHL+HA group) were closed abdominally by using 2 mL of sodium hyaluronate gel coated with the damaged abdominal wall and the cecum; the postoperative groups treated with phloretin (the PHL and PHL+HA groups) were treated with 2 mL of40 mg/kg phloretin dissolved in 0.5% sodium carboxymethylcellulose by gavage daily, and the rest of the groups were treated with 2 mL of 0.5% sodium carboxymethylcellulose solution by gavage. After general anesthesia, the rats were executed on the 7th day after surgery, and the Nair’s score was used to evaluate the adhesion status of each group on the 7th day after surgery; the adhesive tissue or normal peritoneal tissue were collected (cecum and its opposite side of the peritoneal tissue was collected in the sham-operation group), and immunohistochemistry was performed to evaluate the degree of staining with Nrf2 antibody, HE staining was performed to evaluate the inflammation scores, and Sirius red staining was performed to evaluate the thickness of the collagen fibers, and levels of transforming growth factor β1 (TGF-β1), malondialdehyde (MDA) and superoxide dismutase (SOD) were measured. Results All rats successfully completed the experiment. Compared with the control group, Nair’s score, inflammation score, expression level of TGF-β1, thickness of collagen fibers in the adherent tissues, and MDA level were significantly lower in the PHL+HA group (P<0.05), but the SOD level and expression lever of Nrf2 were significantly higher in the PHL+HA group (P<0.05). Conclusion Phloretin combined with sodium hyaluronate can prevent the formation of postoperative abdominal adhesions in the rat model, which may be related to reducing inflammation, reducing collagen deposition, activating Nrf2 pathway and inhibiting oxidative stress.