Objective: To clarify that protection of Tongxinluo against myocardial ischemia/reperfusion injury relates to enhancing endothelial barrier in diabetic rats.
Methods: A total of 32 Zucker diabetic rats were randomized into 4 groups:Sham group, Model group, Insulin group and Tongxinluo group, n=8 in each group. In addition, there was a Control group containing 8 non-diabetic Zucker rats. Myocardial ischemia/reperfusion injury model was established by a 45-min ischemia and 3-h reperfusion protocol. The size of infarction was detected by pathological staining, the microvascular permeability was examined by Miles assay to obtain the lfuorescein isothiocyanate concentration in myocardial tissue, the Triton X-100 soluble and insoluble VE-cadherin was measured by membrane protein extraction and western blot analysis.
Results:The size of infarction in Model group was obviously higher than that in Control group (55.2 ± 1.4)%vs (36.2± 1.3)%,P<0.05 and the lfuorescein isothiocyanate concentration was also higher in Model group than Control group. Both insulin group and Tongxinluo group had the similar size of infarction with Model group (36.8 ± 1.2)%vs (38.7 ± 1.1)%, P>0.05. Both insulin group and Tongxinluo group got lower lfuorescein isothiocyanate concentration (all P<0.01) and VE-cadherin internalization (all P<0.05) than that in Model group.
Conclusion: Protection of Tongxinluo against myocardial ischemia/reperfusion injury in diabetic rats is as effective as
insulin, but the effect is independent of reducing blood glucose and may be related to enhancing endothelial barrier.