title: A PKC-beta inhibitor protects against cardiac microvascular ischemia reperfusion injury in diabetic rats.
abstract: PKC-beta inhibitor Ruboxistaurin (RBX or LY333531) can be used to reverse diabetic microvascular complication. However, it has not been previously established whether RBX can protect against ischemia/reperfusion (I/R) injury of cardiac microvessels in diabetic rats. STZ-induced diabetic rats were randomized into four groups and underwent I/R procedures. Cardiac barrier function and the region of cardiac microvascular lesion were examined. Cell monolayer barrier function was detected in cultured cardiac microvascular endothelial cells (CMECs) subjected to simulated I/R (SI/R). PKC-beta siRNA was transfected into CMECs to silence PKC-beta. Apoptosis Index of CMECs was detected by TUNEL assay and phosphor-LIMK2 protein expression was examined by Western blot analysis. RBX and insulin administration significantly reduced the cardiac microvascular lesion region and Apoptosis Index of endothelial cells (all P < 0.05 vs. no-treatment group). RBX decreased phosphor-LIMK2 expression (P < 0.05 vs. no-treatment group). RBX pretreatment and transfection with PKC-beta siRNA induced a rapid barrier enhancement in CMECs monolayer as detected by increased transendothelial electrical resistance (TER) and decreased FITC-dextran clearance (all P < 0.05 vs. no-treatment group). Meanwhile, RBX pretreatment and transfection with PKC-beta siRNA significantly decreased TUNEL positive CMECs and phosphor-LIMK2 expression in cultured CMECs (all P < 0.05 vs. no-treatment group). RBX pretreatment reduced F-actin/G-actin in cultured CMECs, reproducing the same effect as PKC-beta siRNA. These data indicate that PKC-beta inhibitor (RBX) may be helpful in attenuating the risk of severe cardiac microvascular I/R injury in diabetic rats partly due to its maintenance of endothelial barrier function and anti-apoptotic effect.
authors.affiliation: Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Wei
authors.forename: Dongdong
authors.initials: D
authors.lastname: Sun
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Yin
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yuan
authors.forename: Andrew
authors.initials: A
authors.lastname: Hwang
authors.forename: Yingmei
authors.initials: Y
authors.lastname: Zhang
authors.forename: Rui
authors.initials: R
authors.lastname: Si
authors.forename: Rongqing
authors.initials: R
authors.lastname: Zhang
authors.forename: Wenyi
authors.initials: W
authors.lastname: Guo
authors.forename: Feng
authors.initials: F
authors.lastname: Cao
authors.forename: Haichang
authors.initials: H
authors.lastname: Wang
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000150:complications* / Q000201:enzymology / Q000473:pathology; D015536:Down-Regulation / Q000187:drug effects; D017097:Electric Impedance; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D005947:Glucose / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology / Q000627:therapeutic use*; D054461:Lim Kinases / Q000378:metabolism; D008297:Male; D008301:Maleimides / Q000494:pharmacology / Q000627:therapeutic use*; D055806:Microvessels / Q000187:drug effects / Q000201:enzymology / Q000473:pathology* / Q000648:ultrastructure; D009206:Myocardium / Q000201:enzymology / Q000473:pathology / Q000648:ultrastructure; D020011:Protective Agents / Q000627:therapeutic use; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000378:metabolism; D064546:Protein Kinase C beta; D047428:Protein Kinase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000150:complications / Q000188:drug therapy* / Q000473:pathology / Q000517:prevention & control*
chemical_list: D000199:Actins; D007211:Indoles; D008301:Maleimides; D020011:Protective Agents; D047428:Protein Kinase Inhibitors; C099154:ruboxistaurin; D054461:Lim Kinases; C490644:Limk2 protein, rat; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D005947:Glucose