Establishment of mouse models of focal cerebral ischemic reperfusion injury combined with diabetes mellitus and expression of relevant inflammatory factors

Objective To establish the mouse models of focal cerebral ischemic/reperfusion(I/R)injury combined with diabetes mellitus(DM), and investigate the possible mechanism of brain injury. Methods Eighty healthy C57BL/6J mouse were randomly divided into normal group and DM group; normal saline or streptozotocin was given to the mice in the two groups via intraperitoneal injection, and the concentration of glucose in peripheral blood was measured at different time points(2, 4, 6 and 8 weeks after injection); and then, the mice in the two groups were subdivided into normal sham-operated group, normal I/R group, DM sham-operated group and DM+ I/R group(n=20). The focal I/R models were induced by thread occlusion method; the neuroethology assessment was determined by Zea Longa method in the normal I/R group and DM+ I/R group; the morphology of the brain tissues in the four groups was observed by HE staining; changes of mRNA expressions of interleukin(IL)-1β, IL-6 and tumor necrosis factor(TNF)-α were analyzed by quantitative real-time PCR. Results (1)The glucose concentration in DM group was stable at a high level within the 8 weeks; as compared with normal group, DM group had significantly higher glucose concentration at each time point(P<0.05).(2)The assessment scores of DM+ I/R group(2.800 ± 0.092)were significantly higher than those of I/R group(1.750±0.123, P<0.05).(3)Typical pathological changes were presented by HE staining, DM+I/R group presented worse damage to the brain as compared with normal I/R group.(4)Quantitative real-time PCR showed that the IL-1β and TNF-α mRNA expressions in the normal I/R group was significantly higher than those in the normal sham-operated group(P<0.05); the mRNA expressions of IL-1β, IL-6 and TNF-α in DM+I/R group were significantly increased as compared with those in the DM sham-operated and normal I/R group(P<0.05). Conclusion The simple and reliable focal cerebral I/R combined with DM models are successfully established; inflammation reaction mediated by inflammatory factors might play an important role in this aggravating damage. Key words: Diabetes mellitus; Cerebral ischemic reperfusion injury; Inflammatory factor; Animal, model