ObjectiveTo investigate the effect of simulated in vivo physiological environment severed limb fostering system applying remote ischemic conditioning (RIC) perfusion on preserving severed limb. MethodEighteen adult Bama mini pigs (24-30 kg in weight) were randomly divided into 3 groups (n=6) . No ischemic treatment was given in group A as normal control group; the right lower limbs were completely amputated and preserved at room temperature for 3 hours to make ischemic models in groups B and C, and then the severed limbs were put into the simulated in vivo physiological environment severed limb fostering system. Continuous blood perfusion was performed in group B, and continuous blood perfusion was performed after RIC perfusion in group C. After 8 hours of perfusion, the skeletal muscle samples were harvested for the morphology observation by transmission electron microscopy. The protein levels of B-cell lymphoma-2(Bcl-2) and Caspase-3 were detected by Western blot. The content of cytochrome C in both mitochondria and cytoplasm was determined by ELISA. ResultsTransmission electron microscopy results illustrated that the muscle fibers arranged more orderly and the mitochondria swelling was slighter in group C than group B. Western blot analysis showed that the protein levels of Bcl-2 and Caspase-3 were significantly higher in groups B and C than group A (P<0.05) ; the protein level of Bcl-2 significantly increased and the protein level of Caspase-3 significantly decreased in group C when compared with those in group B (P<0.05) . ELISA detection implicated that mitochondrial cytochrome C significantly reduced and cytosolic cytochrome C significantly increased in group B when compared with those in groups A and C (P<0.05) , but no significant difference was found between group A and group C (P>0.05) . ConclusionsThe ischemia/reperfusion-induced injury to skeletal muscle could be considerably inhibited by RIC perfusion. The simulated in vivo physiological environment severed limb fostering system applying RIC perfusion can significantly prolong the severed limb preserving time.
Objective To investigate the effects of different intervention time windows of remote ischemic conditioning (RIC) training on cardiac function, myocardial fibrosis, and the myocardial cell death profiles after myocardial ischemia-reperfusion injury (IRI) in mice. Methods C57BL/6 male mice were randomly divided into the sham surgery group, IRI group, pre-ischemia 3-day intervention group, immediate intervention during the ischemic period after left anterior descending artery ligation group, post-reperfusion immediate intervention group, and post-reperfusion 3-day intervention group, with 6 mice in each group. RIC intervention involved limb ischemia for 5 minutes followed by reperfusion for 5 minutes, repeated for 5 cycles. The heart function, myocardial infarction area, degree of myocardial fibrosis, and expression of apoptosis-related proteins, pyroptosis-related proteins, and ferroptosis-related proteins in myocardial tissue were measured. Results Compared with the sham surgery group, the IRI group showed a decrease in left ventricular ejection fraction and left ventricular fractional shortening (P<0.05). Compared with the IRI group, all RIC training intervention groups showed varying degrees of improvement in cardiac function (P<0.05), and the deposition of myocardial collagen fibers was reduced. Compared with the IRI group, the pre-ischemia 3-day intervention group showed a decrease in Bax and cleaved-caspase-3 protein expression and an increase in Bcl-2 protein expression (P<0.05). The myocardial infarction area was reduced in the immediate intervention during the ischemic period after left anterior descending artery ligation group (P<0.05). The expression of GPX4 and xCT proteins increased in the post-reperfusion immediate intervention group (P<0.05). The expression of GPX4 and xCT proteins increased, while the expression of nucleotide-binding domain leucine-rich repeat and pyrin domain-containing receptor 3 and caspase-1 proteins decreased in the post-reperfusion 3-day intervention group (P<0.05). Conclusion Different time windows of RIC can alleviate cardiac dysfunction and myocardial fibrosis in mice with myocardial IRI to varying degrees, and their protective effects vary across different intervention time windows.