The Mechanism Of Action Of NECA Protect Myocardial Ischemia Reperfusion Injury

Objectives To study the role of autophagy, mitochondrial and endoplasmic reticulum stress in cardio-protection of NECA against ischemia reperfusion injury.Methods Wistar rats of SPF grade were divided into Sham group, I/R group, NECA group and TUDCA group. We established the isolated rat heart ischemia reperfusion model by using the device of Langendorff. Cardiac tissue samples were collected from the ischemic zone 120 min after the onset of reperfusion. Transmission electron microscope was used to evaluate alterations of the myocardial ultrastructures in the setting of ischemia reperfusion. Western blot analysis was used to determine IRE1α, XBP1 s, Beclin1 and LC3 expression. Immunohistochemical staining was used to detect the expression of IRE1α and LC3. Mitochondrial swelling experiment was aimed to estimate the degree of m PTP opening.Results 1 Transmission electron microscopy analysis showed that compared to the Sham group, I/R can induced cellular structure disorder, mitochondrial swelling, mitochondrial damage, crest disappeared, edema or a vacuolar degeneration, autophagy and autolysosome wrapped with mitochondria, and an effect was alleviated by both NECA and TUDCA. 2 Western blot analysis showed that I/R can up regulate the expression of IRE1α,XBP1 s, Beclin1 and LC3 contrast to Sham group(P<0.05), but these effect were inhibited by both NECA and TUDCA(P<0.05). 3 Immunohistochemistry staining showed that Sham group have no claybank positive staining area, heart ischemia reperfusion significantly increased positive area,and this condition was relieved by both NECA an TUDCA. 4 Mitochondrial swelling experiments showed that the extent of mitochondrial swelling was increased after I/R in comparison to Sham group(P<0.05), both NECA and TUDCA can reverse this effect induced by I/R(P<0.05).Conclusions NECA can induce cardioprotection through inhibiting endoplasmic reticulum stress, decreasing autophagy and alleviating mitochondrial damage against myocardial ischemia reperfusion injury.