| Objective:To observe the expression of IKK and IκBαphosphorylated at different period in the heart of STZ diabetic rats , and the change of myocardium structure . To explore the role of IKK and IκBαPhosphorylated in the development of diabetic cardiomyopathy .Methods: 48 Wistar rats were divided randomly into two groups. 24 rats in normal control group and 24 rats in diabetes mellitus group. The subjects in diabetes mellitus group were injected intraperitoneally with dose STZ 50mg/kg while the ones in normal control group were injected intraperitoneally with the similar dose of citric acid buffer. We determined blood glucose by shearing tails after 72h . The standard of diabetes mellitus rats was blood glucose greater than or equal to 16.7mmol/L . At 4,8 and 12 weeks, collecting the blood of heart after anaesthesia , cutting the cardiac muscle at the same part of aortic ventricle of heart , and weight , index of heart weight , area of heart cell and C peptide in the blood were measured at the same time . The cardiac muscle was fixed and embedded, the pathological changes of cardiac muscle were examined using light microscope and electron microscope. Expression of IKK and IκBαPhosphorylated in the Heart of STZ Diabetic Rats were determined by immunohistochemistry.Results: 1. At the experimental period , diabetic rats display evident hyperdiuresis , polydipsia , polyphagia and athrepsy . The weight of normal control group increased . There was a significant difference at 4 week , 8 week and at 12 week (P<0.01) . Diabetic group kept the level of hyperglycaemia and the level of low C peptide , but normal control group kept the normal level . There was a significant difference between two groups (P<0.01). The fast blood glucose of diabetic group sustained at high level and the C peptide maintained at low level after 1week while the control group was normal. The index of heart weight was more incremental in diabetic group than in normal control group at 12 week , and there was a significant difference between two groups (P<0.01) . Cell area of cardiac muscle was more incremental in diabetic group than in normal control group at 8 and 12 week , and there was a significant difference between two groups (P<0.01) .2. Compared with normal control group, hypertrophy , rarefaction , collapse of myofibril were more obvious in diabetic group by light microscope at 8 week ,and increase of ecto- matrix of cardiac muscle and fibrosis were more obvious at 12 week . In normal control group, arrangement of myofilament was concinnous , and framework of mitochondrion was limpid . By electron microscope , in diabetic group , rarefaction of arrangement of myofilament , engorgement and deformation of mitochondrion even disruption , and arrange disord of cristae were observed . With the progress of course of disease , the affection was gradually s aggravated .3 . Immunohistochemisty showed that the expression of IKK phosphorylated in the tissue of cardiac muscle was much higher than normal control group(P<0.01), IκBαphosphorylated also more expression than the control group(p<0.01), they increased continually during the whole experiment .There was a significant positive correlation between the expression of IKK phosphorylated and IκBαphosphorylated in the tissue of cardiac muscle in DM group at 4,8 and 12 week (r=0.976,P<0.01) .Conclusion:While the expression of IKK phosphorylated and IκBαphosphorylated enhanced gradually in diabetic group in myocardial cell , diabetic cardiomyopathy aggravated gradually . We can make a conclusion: in the progress of diabetic cardiomyopathy , IKK and IκBαplay a important role .
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