A PKC-beta inhibitor protects against cardiac microvascular ischemia reperfusion injury in diabetic rats

Apoptosis. 2010 Apr;15(4):488-98. doi: 10.1007/s10495-009-0439-2.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Apoptosis / drug effects
  • Diabetes Mellitus, Experimental / complications*
  • Diabetes Mellitus, Experimental / enzymology
  • Diabetes Mellitus, Experimental / pathology
  • Down-Regulation / drug effects
  • Electric Impedance
  • Endothelial Cells / drug effects
  • Endothelial Cells / enzymology
  • Endothelial Cells / pathology
  • Glucose / pharmacology
  • Indoles / pharmacology
  • Indoles / therapeutic use*
  • Lim Kinases / metabolism
  • Male
  • Maleimides / pharmacology
  • Maleimides / therapeutic use*
  • Microvessels / drug effects
  • Microvessels / enzymology
  • Microvessels / pathology*
  • Microvessels / ultrastructure
  • Myocardium / enzymology
  • Myocardium / pathology
  • Myocardium / ultrastructure
  • Protective Agents / therapeutic use
  • Protein Kinase C / antagonists & inhibitors*
  • Protein Kinase C / metabolism
  • Protein Kinase C beta
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinase Inhibitors / therapeutic use*
  • Rats
  • Rats, Sprague-Dawley
  • Reperfusion Injury / complications
  • Reperfusion Injury / drug therapy*
  • Reperfusion Injury / pathology
  • Reperfusion Injury / prevention & control*


  • Actins
  • Indoles
  • Maleimides
  • Protective Agents
  • Protein Kinase Inhibitors
  • ruboxistaurin
  • Lim Kinases
  • Limk2 protein, rat
  • Protein Kinase C
  • Protein Kinase C beta
  • Glucose