Effects Of Estrogen, Phytoestrogens On The Vascular Permeability Of Ovariectomized Rats And The Underlying Mechanisms

Objective:Phytoestrogens possess a variety of physiological activities. They can reduce mortality from cardiovascular disease; reduce osteoporosis risk; reduce menopausal symptoms and also have better prevention to hormone-dependent tumors. It has been informed by most researchers that phytoestrogens have a protective effect for the cardiovascular system, but few papers have been reported about the effects of phytoestrogens on vascular permeability. Therefore, in the present experiment, we use ovariectomized rats as model to compare the effects of estrogen, progesterone and phytoestrogens on vascular permeability and to study the underlying mechanisms.Methods:Ovariectomized rats were subcutaneously given different doses of 17β-estradiol(0.01 mg-kg-1,0.1 mg-kg-1 or 1 mg-kg-1),17p-estradiol combined progesterone, progesterone, or genistein, resveratrol, phloretin 21 days, all rats were killed, the uterine, aorta and breast were removed:1. To weigh the uterine weight and analyse the effects of estrogen, progesterone and phytoestrogens on it; 2. Hematoxylin-eosin staining were used to revealed the eosinophilic infiltrations in uterine wall; 3. The factors TNF-a, NF-κB, P-AKT, AKT and HIF-la closely relating with the vascular permeability were observated by immunohistochemical method, sham-ovariectomized rats were used as control.Results:(1) Changes of uterine weight in ovariectomized rats after treated with different doses of Est and Pro:Compared with sham-ovariectomized rats, the uterine weight of ovariectomized rats reduced mostly. After administering Est(0.01 mg-kg-1,0.1 mg-kg-1,1 mg-kg-1), it increasd. After treated with 1 mg-kg-1 Est, the uterine weight even pass normal. At the same time, the group of Est+Pro resulted in a sharply increased. Progesterone also had the same results, but the effects was weaker than Est.(2) Observations of leukocyte leakage in uterine wall:When rats were ovariectomized and given no subsequent hormone replacement therapy, uterine wall eosinophilic infiltration was not express, after treated with Est or Est+Pro, a mass of eosinophilic infiltration was found. Conversely, after treated with Pro, Gen, Res, Phl, eosinophilic infiltration was not observed(3) The observation of TNF-αexpression in uterine tissue:The expreesion of TNF-a mainly lied in cytoplasm of covering epithelium cell, mesenchymal cell, glandular epithelium cell and smooth muscle cell in uterine tissue. In uterine tissue, TNF-a was expressed at different level in different treatment groups. To compare with sham group, the TNF-a expression of Ovx group was negtive. However, to compare Ovx+Est, Ovx+Est+Pro group with Ovx group respectively, the expression of TNF-a were up-regulated. Gen, Res and Phl had no obvious effect on the expression of TNF-a in Ovx rats.(4) The observation of NF-κB expression in uterine, aortic and breast tissue:The expreesion of NF-κB in uterine tissue mainly lied in cytoplasm of covering epithelium cell, mesenchymal cell, glandular epithelium cell and smooth muscle cell.In vascular tissue, the NF-κB expression mainly lied in cytoplasm or nucleolus of vascular endothelial cell and vascular smooth muscle cell. In breast tissue, it mainly lied in alveoli cell and smooth muscle cell cytoplasm. NF-κB was expressed at different level in every group. To compare with sham group, the NF-κB expression of Ovx group was down-regulated. However, to compare Ovx+Est, Ovx+Est+Pro, Ovx+Pro group with Ovx group respectively, the expressions of NF-κB were all up-regulated. Gen, Res and Phl had no obvious effect on the expression of NF-κB in Ovx rats.(5) The observation of P-AKT, AKT expression in uterine, aortic tissue:The results indicate that there have no differ between the groups.Conclusions:1. Est alone or in combination with Pro increases uterine eosinophilic infiltration which is related with vascular hyperpermeability caused by NF-κB and TNF-a, whereas phytoestrogen Gen, Res, and Phl has no such an effect.2. The expression of NF-κB in ovariectomized rats uterine, aortic and breast tissues were down-regulated; after administer Est and Pro, it was significantly increased; However, Gen, Res and Phl had no obvious effect on the expression of them.