Protective Effect Of Calpain Inhibitor Calpeptin On Intestinal Ischemia Reperfusion Injury

Background:Intestinal ischemia-reperfusion(I/R)injury is a frequent and devastating complication in clinical settings with high morbidity and mortality,often leading to systemic inflammatory response syndrome(SIRS)and multiple organ dysfunction syndrome(MODS).The oxidative stress injury caused by reactive oxygen species(ROS)plays a key role in contributing to intestinal IR injury.Oxidative stress injury occurs when intracellular ROS level increases and/or when intracellular anti-oxidative mechanism weakens due to various factors.Among anti-oxidative mechanisms,hypoxia-inducible factor-2a(HIF-2a)has exhibited a critical protective effect against oxidative stress.It has been proven that HIF-2a can be degraded by activated calpains,therefore reducing the expression of downstream genes of anti-oxidative enzymes and causing oxidative stress injury.It is widely known that calpains can be activated during ischemia-reperfusion process,but it was never reported whether the activation of calpains,the degradation of HIF-2a it causes and the subsequent oxidative stress injury truly function in that order,specifically during intestinal IR process.Therefore,the hypothesis of the research study is that:Actived calpains by intestinal IR promoting HIF-2a degradation and redusing the expression of its target gene which acusing oxidative stress.Calpain-specific inhibitor calpeptin ameliorates oxidative stress to protect intestinal IR injury via decreasing HIF-2a degradation.Objective:This study examined the role of Calpain/HIF-2a signaling pathway in the pathogenesis of intestinal IR injury and aimed to explore whether inhibition of Calpain by the specific inhibitor Calpeptin can protect against intestinal IR injury though decreasing HIF-2a degradation.Methods:Thirty-two C57BL/6 male mice were randomly divided into four groups(n=8)as follows:(1)a sham group,(2)sham+calpeptin(0.6mg/kg)group(3)I/R group,(4)I/R+calpeptin(0.6mg/kg)group.The mices in the I/R and I/R+calpeptin groups were subjected to 45 min ischemia by clamping the superior mesenteric artery followed by 4 h reperfusion.The sham and sham+calpeptin groups underwent a surgical procedure that were only given appropriate separation of the superior mesenteric artery without occlusion.Mices received a tail-vein injection of calpeptin or vehicle 30 min before the surgeries.Intestinal tissues were separated and collected for assessment.After hematoxylin-eosin(HE)staining,pathology scores were documented according to observations on the pathological changes of the mice intestinal tissues.MDA and total SOD tests were performed on the serum of centrifuged blood.Calpainl,a-Fodrin,HIF-2a,and SOD2 protein levels of the intestinal tissues were tested by the Western-blot method.Calpain activity was measured based on the calpainl protein and 150KDa molecular weight a-Fodrin fragment levels.Results:Intestinal I/R led to significant small intestinal dysfunction with increased mucosal injury;calpainl protein levels of the intestinal tissues largely decreased,and 150KDa molecular weight fragment of the calpain specific target protein a-Fodrin increased,which indicated a higher level of calpain activity during the intestinal I/R:HIF-2a showed no perceivable difference in mRNA levels but considerable decrease in protein levels;SOD2 protein showed lower levels of expression;serum MDA levels increased while overall SOD levels obviously decreased.However it can be all reversed by the calpain-specific inhibitor calpeptin.Conclusion:1.Calpain activity heightened the degradation of HIF-2a and reduced the expression of its downstream target gene(SOD2 gene)during a intestinal I/R,which increased the production of reactive oxygen species(ROS)and caused oxidative stress damage.2.Employment of calpain-specific inhibitor calpeptin is successful in suppressing calpain activity and ameliorating oxidative stress injury though decressing HIF-2a degradation.Objective:To investigate the high risk factors and diagnose and treatment of male bilateral primary breast cancer.Methods:The high risk factors and the clinical data of one case confirmed by surgery and pathology of male bilateral primary breast cancer were retrospectively analyzed and reviewed the particularity of the diagnose and treatment with the literatures relevant to this disorder.Results:This patient has no special risk factors.20 years ago,the patient admitted to hospital due to right breast tumor,preoperative diagnosis:the right of breast cancer.Intraoperative frozen section pathology:breast cancer.Pathologically confirmed:male breast cribriform carcinoma without lymph node metastasis.20 years later,the patient admitted to hospital again because of left breast tumor.Preoperative diagnosis:left breast tumor,malignant probability.Intraoperative frozen pathology:left breast cancer.Pathologically confirmed:left breast Non-specific invasive breast cancer.Immunohistochemical results:ER90%moderately positive,PR90%strongly positive,Her-2(2 +),P53 10%moderatly positive,TOPOI(-),Ki67 index 10%,EGFR(-).According to the result of pathology,confirmed that this case is male bilateral primary breast cancer.Conclution:The male breast cancer pathogenesis and treatment has not clear standard.Early diagnosis of male breast carcinoma should be emphasized.Aggressive surgery combined with other auxiliary treatments are effective.