ABSTRACT
AIM:To study the effect of gossypol on the cognitive function of type 2 diabetic rats,and to explore its mechanism. METHODS:Thirty male Sprague-Dawley rats were divided into three groups randomly:normal group,type 2 diabetic group and gossypol treated group. After fed with high-fat diet for 4 weeks,the later two groups were injected with streptozotocin intraperitoneally to establish type 2 diabetic rat model. The animals in gossypol treated group were given gossypol at dosage of 15 mg/kg once per day for 4 weeks by gavage. Since 5th week,the times of gavages were changed into once per week at the same dosage and lasted to 12th week. Learning and memory abilities of rats were assayed with Morris water maze test. The concentration of blood glucose was measured by biochemical method. The levels of serum corticosterone and insulin were detected by enzyme-linked immunosorbent assay and radioimmunoassay,respectively. The protein expressions of 11?-HSD1 and GR in cerebral cortex and hippocampus were determined by Western blotting. The morphological changes of cerebral cortex and hippocampus were observed under light microscope and transmission electronic microscope,respectively. RESULTS:Compared to normal group,the karyopyknosis,dilation of golgiosome and mitochondria swelling of neuron from cerebral cortex and hippocampus were prominent in diabetic group. The concentrations of blood glucose,serum corticosterone and insulin increased significantly (P
ABSTRACT
AIM:To study the effect and mechanism of extract of ginkgo biloba(EGB) on liver glucocorticoid receptor(GR) expression in type 2 diabetic rats.METHODS:Thirty male Sprague-Dawley rats were divided randomly into three groups:normal control group(n=10),type 2 diabetic group(n=10) and ginkgo biloba treated group(n=10).After fed with high-fat feeding for 4 weeks,the later two groups were injected with streptozotocin at a dose of 30 mg/kg intraperitoneally to induce type 2 diabetic rat model.The EGB treated group was gavaged with EGB at the dose of 50 mg?kg-1?d-1 for 12 weeks.At the end of experiment,the rats were sacrificed,the blood glucose,serum lipid and blood insulin were measured.The morphology of liver tissue was observed under light microscopy with HE staining.GR mRNA expression in liver was measured by RT-PCR.The level of GR protein expression in liver tissue was detected by immunohistochemistry.RESULTS:EGB reduced the levels of blood glucose,blood lipids,blood insulin in diabetic rats.EGB also relieved fatty degeneration and necrosis of the hepatic cells,ameliorated infiltration of inflammatory cells in the liver;and decreased GR expression at both mRNA and protein levels in diabetic liver.CONCLUSION:EGB may inhibit GR expression in liver of type 2 diabetic rats,which results in decreasing the level of blood glucose,blood lipid,blood insulin and relieving the liver damage in type diabetic rats.
ABSTRACT
AIM:To observe the effect of the extract of Ginkgo biloba(EGB)on pituitary-testicular axis and the mRNA expressions of luteinizing hormone receptor(LHR)and steroidogenic acute regulatory protein(StAR).METHODS:Thirty male Sprague-Dauley rats were divided into three groups randomly:normal control group,type II diabetic group and EGB treatment group.After fed with high-fat diet for 4 weeks,the later two groups were injected with strepozotocin intraperitoneally to induce type II diabetes mellitus.The EGB treatment group was given EGB at the dose of 50 mg/kg once a day for 12 weeks by intragastric administration.The normal control and diabetic group were given normal saline of equal volume per day for 12 weeks.The indices of blood glucose,insulin and low-density lipoprotein-cholesterol(LDL-c)were measured.The morphologic change of testicular tissue was observed under light microscopy(LM)and transmission electron microscopy(TEM)respectively.The concentrations of blood luteinizing hormone(LH)and testosterone(T)were assayed by the technique of enzyme linked immunosorbent assay(ELISA).The mRNA expressions of LHR and StAR from Leydig cells were detected by RT-PCR.RESULTS:The concentrations of blood glucose,insulin and LDL-c increased obviously,and the testis weights lessened obviously in type II diabetic groups compared to those in normal control groups.Rare spermatogenic cells of seminiferous tubule and germinal arrest were observed in diabetic group under LM.Ultrastructural analysis of testicular tissue by TEM showed dilation of the endoplasmic reticulum and mitochondrial swelling in Leydig cell and sertoli cell in diabetic group.The level of blood LH and T decreased in typeⅡ diabetic groups in comparison with that in the normal control group.Compared to normal groups,the mRNA expression of StAR in type Ⅱ diabetic groups decreased,while the mRNA expression of LHR increased.After the treatment of EGB,the pathological change of testis was relieved,the concentrations of blood glucose,insulin and LDL-c were decreased,the level of blood LH and T,and the mRNA expression of StAR were increased,and the mRNA expression of LHR descended compared to type Ⅱ diabetic groups.CONCLUSION:EGB may increase the LH-induced testosterone production by correcting metabolic disorder of glucose and lipid,improving the function of pituitary-testicular axis and regulating the expression of LHR and StAR mRNA.