| Objective The purpose of this study was to investigate the ability of coenzyme Q10(CoQ10)to attenuate focal cerebral ischemia/reperfusion(I/R)injury in hyperglycemic/diabetic rats and its possible relationship with mitochondria fission and fusion,as well as mitochondria autophagy.Methods The rats were injected with streptozotocin to induce diabetic hyperglycemia.After raising for four months,carry out drug treatment for one month.Focal cerebral ischemia was induced by transient middle cerebral artery occlusion(MCAO)for 30 min.To investigate the role of CoQ10 in hypoglycemia / diabetes mellitus-induced cerebral ischemia-reperfusion injury and its relationship with mitochondrial division / fusion in the development of this disease.The rats were randomly divided into four groups: ? the normal blood glucose group;?hyperglycemia group: the rats were fasted overnight and injected intraperitoneally with STZ(60 mg/kg).Diabetes was confirmed by measurements of blood glucose levels 2days after STZ injection using a OneTouch glucometer.Animals with a blood glucose level higher than 16.8 mmol/L were designated the diabetic group.?CoQ10 intervention group:CoQ10(10 mg/kg,CoQ10 was prepared in a 1% aqueous solution of Tween 80)was administered intramuscularly for the 4 week duration of treatment starting after the induction of diabetes.?insulin therapy group: The rats were pretreated with insulin(2 U/d,subcutaneous injection)for 4 weeks following focal cerebral ischemia.During the treatmentperiod,blood glucose was assessed every three days.To maintain normal blood glucose levels,the amount of insulin was adjusted based on the blood glucose level.Each group was divided into sham and I/R 24 or 72 h.Using the Zea-Longa scoring and Feeney scoring standard to obtain a neurological score,Spontaneous altemation on a T-maze to test their behavior;2,3,5-triphenyltetrazolium chloride(TTC)staining were applied to detect the extent of the damage.The expression of Fis1,Mfn2,OPA1,DRP1,NeuN,GFAP,Iba1 in the brain was investigated by immunohistochemical and Western blotting techniques.The expression of Lc3 was determined by Western blotting.Results ? Physiological parameters: There were no significant differences of body weight among NG,HG,CoQ10,and insulin groups.The CoQ10 intervention group exhibited lower blood glucose.? After 24 h,ischemia-reperfusion of the infarction area of the hyperglycemia group was significantly increased relative to that of the normal group(P<0.05),and the score of neurological deficit was significantly increased(P<0.05).CoQ10 treatment significantly reduced the infarct volume and neurological deficits.? The histological observations yielded the same results.HE staining suggested,at 24 h and 72 h after reperfusion,the number of pyknotic cells in the hyperglycemia group was significantly higher than that in the normal group(P<0.05),at 24 h after reperfusion,the number of pyknotic cells in the hyperglycemia group group was more than that in the CoQ10 intervention group(P<0.05).?Nissl staining suggested,the number of viable neurons in the hyperglycemia group was significantly lower than that in the normal group(P <0.05),at 24 h and 72 h after reperfusion,and the number of viable neurons in the hyperglycemia group was less than that in the CoQ10 intervention group(P <0.05);After 24 and 72 h of I/R,IOD of Nissl bodies in the hyperglycemia group was significantly lower than that in the normal group(P <0.05),in the hyperglycemia group was less than that in the CoQ10 intervention group(P <0.05).?After 24 and 72 h of I/R,the number of Fis1 positive cells in the hyperglycemia group was significantly higher than that in the normal blood glucose group,and the Fis1 positive cells inthe CoQ10 group were significantly decreased in comparison to those in the hyperglycemia group(P<0.05).After 24 and 72 h of I/R,the number of Drp1 positive cells in the hyperglycemia group was significantly higher than that in the normal blood glucose group,and the Drp1 positive cells in the CoQ10 group were significantly decreased in comparison to those in the hyperglycemia group(P<0.05).After 24 and 72 h of I/R,Mfn2-positive cells in the hyperglycemia group were significantly decreased relative to those in the normal glucose group(P<0.05).Relative to the hyperglycemia group,the CoQ10 group showed an increase in the number of Mfn2-positive cells after 72 h of reperfusion(P<0.05).After 24 and 72 h of I/R,the number of OPA1 positive cells in the hyperglycemia group was significantly lower than that in the normal blood glucose group,and the OPA1 positive cells in the CoQ10 group were significantly increased in comparison to those in the hyperglycemia group(P<0.05).After 24 and 72 h of I/R,the number of NeuN positive cells in the hyperglycemia group was significantly lower than that in the normal blood glucose group,and the NeuN positive cells in the CoQ10 group were significantly increased in comparison to those in the hyperglycemia group(P<0.05).After 24 and 72 h of I/R,the number of GFAP positive cells in the hyperglycemia group was significantly higher than that in the normal blood glucose group,and the GFAP positive cells in the CoQ10 group were significantly decreased in comparison to those in the hyperglycemia group(P<0.05).After 24 and 72 h of I/R,the number of Iba1 positive cells in the hyperglycemia group was significantly higher than that in the normal blood glucose group.After 72 h of I/R,the Iba1 positive cells in the CoQ10 group were significantly decreased in comparison to those in the hyperglycemia group(P<0.05).?Western blotting analysis showed that for the expression of the membrane-bound form of Lc3B-II/I protein and mitochondrial mitotic protein Fis1 and P-Drp1/Drp1(P<0.05),in the 24 and 72 h of reperfusion,the levels in the hyperglycemia group were significantly higher than those of the normal group,and the levels in the CoQ10 group were significantly lower than those of the hyperglycemia group(P<0.05).The change in expression level of themitochondrial fusion protein Mfn2 and OPA1 was the opposite,in contrast with the first two proteins(P<0.05).Conclusion The diabetic/hyperglycemia aggravatess focal cerebral ischemia-reperfusion injury.CoQ10 may play a neuroprotective role by stabilizing mitochondrial disintegration / fusion process and attenuating hyperglycemia and aggravating focal cerebral ischemia-reperfusion injury. |
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