Objective      To study the role of connexin43 (Cx43) in protecting rat myocardium against ischemia/reperfusion (I/R) injury in vitro at sevoflurane post-conditioning.       Methods      Forty healthy adul

t male SD rats

weighing 200-250 g

were randomly divided into I/R group

sevoflurane post-conditioning group (group S)

combined sevoflurane and 5-HD group (group SH)

and 5-HD group (group H)

10 in each group. In vitro heart was perfused with a Langendoff device for 10 min before the left coronary artery was occluded. The left coronary artery was reperfused after its blood flow was occluded for 30 min followed by 120 min-reperfusion. HR

LVSP

LVDP

and  dp/dt

max

were recorded at occlusion of left coronary artery (T0)

intermediate reperfusion (T1)

15 min-reperfusion (T2) and 135 min-reperfusion (T3)

respectively. After reperfusion

myocardial infarct size was measured with TTC staining and expression level of Cx43 and its phosporylation protein p-Cx43 was measured with immunohistochemistry staining and Western blotting

respectively.       Results      The HR

LVSP and  dp/dt

max

were higher

the LVDP was lower

the myocardial infarct size was smaller

and the expression level of Cx43 and its p-Cx43 was higher in group S than in I/R group (P0.05). However

no difference was found in the above parameters among I/R group

group SH and group H (P0.05).       Conclusion      The role of Cx43 in protecting rat myocardium against I/R injury in vitro at sevoflurane post-conditioning may be related with the open mito-KATP

and thus promote expression of Cx43 and its p-Cx43.