Diazoxide ameliorates microcirculatory disturbances through PKC-dependent pathway in I/R-injured rat cremaster muscles.
Diazoxide is a selective mitochondria ATP-sensitive potassium (K(ATP)) channel opener, which has been reported to preserve the microvascular integrity of ischemia-reperfusion (I/R)-injured tissues. Our study aimed to assess diazoxide's effects on I/R-injured cremaster muscles and to further elucidate its underlying mechanisms. Male Sprague Dawley (SD) rats were randomized (n = 8 per group) into four groups: sham-operated control group, I/R group (4 h of pudic epigastic artery ischemia followed by 2 h of reperfusion), diazoxide + I/R group, and chelerythrine (PKC inhibitor)+diazoxide+I/R group. Microscopically, we observed that I/R markedly increased the number of rolling, adhering, and transmigrating leukocytes. I/R also markedly decreased the number of functional capillaries. Biochemically, we found that I/R significantly increased TNF-alpha, E-selectin,L-selectin and P-selectin expressions. However, I/R did not cause significant changes in ICAM-1 and PECAM-1 expressions. On the other hand, in I/R + diazoxide group, we found that diazoxide reduced the number of rolling, adhering, and transmigrating leukocytes. Furthermore, biochemical study revealed that diazoxide caused only a decrease in L-selectin expression but had no effect on TNF-alpha, E-selectin, P-selectin, ICAM-1, and PECAM-1 expressions. Finally, in chelerythrine + diazoxide + I/R group, we observed that diazoxide's protective effects were blocked by the addition of chelerythrine. Diazoxide's ability to protect against I/R injury was confirmed by the observation that it reduced the number of rolling, adhering, and transmigrating leukocytes, and increased the number of functional capillaries. Our results indicated that diazoxide operated via a PKC-dependent pathway to achieve protection against I/R injury.
Wei
William
W
Department of Life Science and Plastic & Reconstructive Surgery, College of Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan.
Wei
Fu-Chan
FC
Hung
Li-Man
LM
D000009:Abdominal Muscles / Q000098:blood supply* / Q000187:drug effects; D000470:Alkaloids; D000818:Animals; D053119:Benzophenanthridines; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism; D003981:Diazoxide / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D007150:Immunohistochemistry; D019041:L-Selectin / Q000378:metabolism; D036904:Leukocyte Rolling / Q000187:drug effects; D008297:Male; D008833:Microcirculation / Q000187:drug effects*; D010617:Phenanthridines / Q000378:metabolism / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000517:prevention & control*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000470:Alkaloids; D053119:Benzophenanthridines; D015815:Cell Adhesion Molecules; D016207:Cytokines; D010617:Phenanthridines; D014409:Tumor Necrosis Factor-alpha; D019041:L-Selectin; C016299:chelerythrine; D011493:Protein Kinase C; D003981:Diazoxide