Abstract:

Objective To explore the mechanism of metabolic abnormality or without exacerbating ischemic brain injury by establishing tree shrew models with type 2 Diabetes mellitus (T2DM), combined with the cerebral ischemia or not. Methods Thirty-six tree shrews were randomly devided into 4 groups: control, ischemia, T2DM and T2DM combined with cerebral ischemia groups. The experimental diabetes model was established by the use of high lipid breeding combined with streptozocin (STZ) injection in tree shrews. The local cerebral thrombosis was induced by photochemical reaction in tree shrews. The metabolic status of the body was measured by serum biochemical markers. 2,3,5-triphenyl tetrazolium chloride(TTC) staining, HE staining and trunsmission electron microscopy were used to observe the changes of the body’s metabolic status at hour 24 after the most prominent clinical manifestations. Results The body weight of tree shrews in the T2DM and T2DM combined with cerebral ischemia groups was decreased (120.29±13.82)g, but there was no statistical difference(P>0.05). Fasting blood glucose (FBG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) were significantly higher, and their values were (26.75 ± 10.60）mmol/L,（7.40 ± 3.26) mmol/L,（2.93±0.70）mmol/L,（1.93±0.63）mmol/L, respectively(P<0.05) in T2DM group, and (32.29±6.08) mmol/L, (7.80 ± 3.41) mmol/L, (3.06 ± 0.95) mmol/L and (1.73 ± 0.29) mmol/L, respectively(P<0.01) in T2DM combined with cerebral ischemia group. Serum C-reactive protein (CRP) level was obviously increased (1.43± 0.53) mg/L(P<0.01). The changes of the above indicators were more obvious when T2DM was combined with cerebral ischemia and the neurons were damaged and the area of cerebral infarction was significantly increased (19.56 ±1.25) % (P<0.01). Conclusion The metabolic abnormality of T2DM tree shrews can aggravate ischemic brain injury, and its mechanism may be related to the inflammatory response caused by the synergistic effect of CRP.

Key words: Photochemistry, Cerebral ischemia, Type 2 diabetes mellitus, Metabolic disorder, C-reactive protein, Transmission electron microscopy, Tree shrew