| Background and aims RANTES (regulated upon activation, normal T cell expressed and secreted) can recruit and activate specific leukocytes in kidney, it causes many renal injuries in the early stage of DM (diabetes mellitus). Many factors also can injury kidney and promote DN(diabetic nepropathy) through changing its expression and secretion. Advanced glycosylation end products (AGEs) is one of the important injury factors involved in the development of DN. Mechanism was not fully clear. The present study aimed to investigate the effects of AGE-BSA and Aminoguanidine (AG), Rosiglitazone(RSG) and Irbestartan(IRB)on the expression of RANTES in cultured human proximal tubule cells (HPTC) and survey RANTES expressed in renal tubule by immunohistochemistry survey .We expect to explore the interaction of AGEs with RANTES and its role in the development of DN on cell and tissure level.Methods The cultured HPTC were conditioned with the same concentrations (20, 40, 100,200,400(g/ml) of AGE-BSA for 48 hours, and with the concentrations (400(g/ml) of AGE-BSA for 4,8,24 and 48 hours respectively. The supernatant was collected, and the cells were harvested to extract total RNA. The supernatant concentrations of RANTES were quantified using ELISA. The mRNA levels of RANTES of conditioned HPTC were evaluated by semi-quantity RT-PCR. DM rats was induced by injection of STZ intraperitoneally as research subjects, the sersum level of AGE-peptides (AGE-P) was examined by fluorescence spectroscopy, RANTES expressed in renal tubule was determined by immunohistochemistry,blood glucose,24 - hour urinary albumin excretion ( 24hUalb) ,HbAlc,BUN and profile of kidney hypertrophy (kidney weight/ body weight) were observed . The data were analyzed with Prizm 3.0 statistical package.Results HPTC has its basal level of RANTES protein (59±6.2 pg/ml). AGE-BSA upregulated the RANTES protein level as dose (40 μg/ml:76±8.0 pg/ml; 100 μg/ml: 205±24 pg/ml; 200 μg/ml:345±35 pg/ml; 400 μg/ml:485±41 pg/ml) and time manner(4h:72±7.8 pg/ml; 8h:260±15 pg/ml; 24h:340±28 pg/ml;48h:480±38 pg/ml;) Aminoguanidine (0.1 mM), Rosiglitazone(1(M) and IRB(1(M) sharply reduced the RANTES protein level induced by AGE-BSA(275±31 pg/ml ,230±27 pg/ml and215±27 pg/ml,vs AGE-BSA 470±40 pg/ml P<0.01,n=3). The results from RT-PCR of RANTES mRNA shows AGE-BSA upregulated the RANTES expression of HPTC as time manner, the peak is in the 48h after intervene. Aminoguanidine(0.1 mM), Rosiglitazone(1(M) and IRB(1(M) sharply reduced the RANTES expression of HPTC induced by AGE-BSA(400 μg/ml 48h) (P<0.001). The serum AGE-P was significantly elevated in DM rat when compared with control subjects (2.24±0.21 μg/ml vs0.80±0.13 μg/ml, P<0.01). BUN ,24 - hour urinary albumin excretion ( 24 h Ualb) and profile of kidney hypertrophy ( kidney weight/ body weight) in DM were also higher than that of control(P<0.01) . RSG and IRB treatment significantly prevented the increase of BUN , 24 - hour urinary albumin excretion ( Ualb) and profile of kidney hypertrophy.( P <0.01 respectively ) . Furthermore ,RSG markedly inhibited the increasing of blood glucose ( P <0.01) ,HbAlc ( P <0.05), and serum AGE-P ( P <0.01) shown in diabetic rats . immunohistochemistry result shows tubular immunostaining for RANTES in DM group is higher than the control group,while RSG and IRB can markedly inhibited the increasing of it.Conclusions Our present studies suggest that: (1) AGE-BSA can upregulate the expression and secretion of RANTES in HPTC as time manner,and upregulate the secretion of RANTES in HPTC as dose manner. (2) AG, RSG and IRB reduce the expression and secretion of RANTES in HPTC induced by AGE-BSA. (3) The serum AGE-P was significantly elevated in STZ DM rat, RSG can reduce it. (4) RSG and IRB can markedly inhibited the increasing of tubular immunostaining for RANTES in DM group,they also markedly inhibited the increasing of 24 - hour urinary albumin excretion ( 24hUalb) ,BUN and profile of kidney hypertrophy to preserve the renal function.
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