| Objective: Explore and study the impact of adiponectin on myocardial lesions and fibrosis intype2diabetic rats,Reveal the vigorous effects of adiponectin on diabetic cardiomyopathy.Methods: Choose40inbreeding and cleaning male Wistar rats，divided into normal controlgroup (n=10) and the experimental group (n=30) randomly. The control group’ rats weregiven normal feed. The experimental group rats offeredabundanthigh sugar feed forfourweeks，then injection of1%STZ (30mg/kg) in the abdominal cavity. The control group injected thesame number of citric acid buffer in the same sit. After72hours, the random blood glucose isgreater than or equal to16.7mmol/L is the succeed rat models.6weeks later, the succeed ratmodels were divided into two groups randomly:(1) diabetic cardiomyopathy group (n=10),(2)adiponectin intervention group (n=11), the latter injections of recombinant adiponectin15ug/kg in the abdominal cavity, once a day. After8weeks, stop the experiences, weighing of allanimals, getting blood from the abdominal aorta, get cardiac muscle in left ventricular region，and make it into the pathological and light microscope slices. Observe histologic changes of thecells and stroma under light microscopy. Using immunohistochemical method determinate theamount of TGF-beta1, type I collagen in tissue. By RT-PCR method determinate mRNAexpression of TGF-beta1and type I collagen in the exercised mice’s heart.Results:1. Light microscopy observation: NC group rat myocardial cell order, myocardial cell outer massis less, the nuclei are round or oval shape, size and distribution are uniformly, cytoplasm staineduniformly, myocardial fibers are disciplinary arranged. DM group rats’myocyte becomehypertrophy, the cells become loose, cells arranged confused, the size of nucleus in theorganization is differ， cytoplasmic stained becomes shallow, myocardial fibers arrangedconfused so far as to become break, the substance of intercellular increased， DA group stillhave pathological change of myocardial cell and muscle fibers, But have different degrees ofease than DM group.2. Though the principle of immunohistochemistry, if it is found that tan particles appear in thearterial tissue, means TGF-beta1located in myocardial. We canobserve, some tan particlesappear in the arterial tissue in NC group, scattered distribution. Tan particle color darker inmyocardial cell cytoplasm of the DM group, extensive and distribution like patchy. It shows thatthe expression of TGF-beta1increased significantly than NC group, tested extraordinary positive. Average grey value (143.82±6.06) of TGF-beta1in DM group rats is significantlylower (P <0.05) than NC group (173.42±6.18), prompt positive expression became higher.Compared with DM group, DA group expressed in the same place, with lighter tan colorparticles, distribution range decreased. Show that the expression quantity less than that of DMgroup. And the average grey value of the TGF-beta1(162.80±7.45) of DA group rat’smyocardial increased significantly (P <0.05) compared with DM group (143.82±6.06), whichprompt positive expression significantly reduced.3. Though the principle of immunohistochemistry, we can see type I collagen located intheintercellular substance. This research found in the NC group, there is nearly no brown dyeingmaterials in theintercellular substance. In the DM group, we can see tan color particles darker inthe intercellular substance, extensive and patchy distributed. Sometimes, connect together justlike a stripe. It shows that the expression quantity increased remarkable compared with normalcontrol group, tested positive. Average grey value (153.14±8.71) of Type I collagen in DMgroup rats is significantly lower (P <0.05) than NC group (194.75±5.11), prompt positiveexpression significantly higher. Compared with DM group, DA group expressed in the sameplace, with lighter tan color particles, like filamentary things, and distribution areaare lessened.Show that the expression quantity less than that of DM group. And the average grey value of theType I collagen (162.80±7.45) of DA group rat’s myocardial increased significantly (P <0.05)compared with DM group (153.14±8.71), which prompt positive show rate significantly reduced.4. This experiment shows, contrast with NC group, the mRNA expression rate of TGF-beta1,type I collagen in DM group rats’ myocardial tissue was significantly higher (P <0.05).10weeks after adiponectin treatment, compared with DM group, the mRNA expression rate of TGF-beta1, type I collagen in DA group rats’ myocardial tissue decreased significantly (P <0.05).Conclusion:1. the myocardial pathologic changes of diabetic rats model consistent with the pathologicalchanges of diabetic cardiomyopathy.2. The reason of the adiponectin can inhibit diabetic rats myocardial fibrosis may be related to itcould reduced the expression of type I collagen and TGF-beta1in myocardial tissue.3. Adiponectin could delay the fibrosis process of diabetic rats. |
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