| Skin flap transfer is a basic plastic surgery method used for wound repair and reconstruction. Although surgical principles and technologies have been improved significantly, flap loss caused by IR injury is still a serious problem to be solved. According to study, cell apoptosis is the main reason that caused IR injury. It has been well documented that JNK signaling pathway is involved in the induction of ischemia/ reperfusion(I/R) injury, and inhibition of JNK activation has been shown to protect heart, brain and renal against I/R injury, but the role of JNK pathway in flap ischemia reperfusion injury has not been in-depth studied, we used SP600125 to study the role of JNK activation in this pathophysiological process. Our previous study showed that hydrogen-rich saline(HRS) attenuated skin ischemia reperfusion injury, and in the present research we studied a link between the protective effect of SP600125 and HRS. The skin flap in the SH group was free from ischemia induction, and after undergoing 3h of I/R management, the rats in surgery groups were respectively treated with normal saline(I/R-P), dimethyl sulphoxide(I/R-D), SP600125(I/R-SP) and HRS(I/R-H). We achieved the main results as follow:1. Optimized the flap ischemia reperfusion injury model in ratFlap ischemia of 3 hours was induced by clamping the left superficial epigastric artery with a microvascular clamp, the injury caused by a short ischemia time can meet the experimental requirement and reduce the vascular damage.2.Al eviated the skin flap IR injury via inhibition of JNK activationWe utilized SP600125, a reversible inhibitor of c-Jun N-terminal kinase(JNK), to study the role of JNK activation in skin flap apoptosis in a rat model of abdomen skin ischemia/reperfusion(I/R). Blood perfusion of flap was measured by Laser Doppler flowmeters, Compared with the I/R-D group, those in I/R-SP group were significantly increased; HE staining was used to observe morphological changes. Early apoptosis was observed through TUNEL staining. The SP600125 management of skin flaps clearly decreased the percentage of apoptotic cel s and inflammatory infiltration compared to the ischemia/reperfusion group; p ASK1, p JNK, Bcl-2 and Bax were examined by immunohistochemistry, the level of p ASK1, p JNK, Bax in I/R-D group was higher than that in I/R-SP group, on the contrary, the Bax was weaker than I/R-SP group.3.The JNK pathway might be one point for the mechanism of HRS's effectWe also studied the link between JNK signal pathways and the effect of hydrogen on skin flap ischemia/reperfusion induced apoptosis via comparing the protective effect of SP600125 and hydrogen-rich saline(HRS). There were no significant differences between skin flap survival area, blood perfusion and cell apoptosis in I/R-H group and I/R-SP group. p ASK1, p JNK, Bcl-2 and Bax were examined by immunodetection. Caspase-3 activity was also measured by fluorometric assay. We mainly achieved the following results: I/R-SP group(vs I/R-D) and I/R-H group(vs I/R-P) were observed with a high expression of Bcl-2 and a low expression of p ASK-1 and p JNK. The Bax was significantly decreased in the SP group. The rats subjected to skin flap ischemia and reperfusion process followed by SP600125 or HRS management presented decreasing in caspase-3 activity compared with the I/R-P and I/R-D group.According to these findings, IR-induced JNK phosphorylation was reduced by SP600125 indicating that JNK mediate the apoptosis pathways in the rat skin and JNK inhibition may act as a novel and effective strategy to prevent ischemic reperfusion injury. In I/R-SP group and I/R-H group, the apoptotic factors measured showed similar expression level which indicated that JNK inhibition during IR may be associated with HRS mediated protection against skin IR apoptosis. |
PDF Full Text Request