ABSTRACT
<p><b>OBJECTIVE</b>To investigate RANK-RANKL expression in the kidneys of a rat model of puromycin aminonucleoside nephropathy (PAN).</p><p><b>METHODS</b>Thirty-six SD rats were randomly divided into PAN model group and normal control group. PAN was induced by a single intravenous injection of 100 mg/kg puromycin aminonucleoside. Serum creatinine and 24-hour urinary protein were measured on days 3, 7, and 14 after the injection, and renal pathologies were assessed with optical and immune transmission electron microscopy. The expression of RANK and RANKL in the kidneys was examined using reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.</p><p><b>RESULTS</b>The PAN model rats showed massive proteinuria and elevated serum creatinine on day 3, which peaked on day 7. RANK-RANKL protein and mRNA expressions in PAN model group was higher than those in the control group. In the PAN rats, RANK was expressed mainly on the top cell membrane and in the cytoplasm of renal podocytes with a significantly increased expression level compared with that in the control group.</p><p><b>CONCLUSION</b>The PAN rat model shows aberrant RANK and RANKL expressions in the podocytes, indicating their contribution to podocyte injury in PAN.</p>
Subject(s)
Animals , Female , Male , Rats , Creatinine , Blood , Kidney , Metabolism , Kidney Diseases , Metabolism , Pathology , Podocytes , Metabolism , Proteinuria , Pathology , Puromycin Aminonucleoside , RANK Ligand , Metabolism , Rats, Sprague-Dawley , Receptor Activator of Nuclear Factor-kappa B , MetabolismABSTRACT
ObjectiveTo evaluate the effects of 1,25(OH)zD3 on podocyte apoptosis in kidney of puremyein aminonueleoside nephropathy (PAN) rats. Methods Seventy-two male Sprague-Dawley rats were randomly divided into three groups: PAN model group(PAN), 1,25 (OH)2D3 treated group (T, 0.2 μg·kg-1d-1 by garages) and normal control group (NC). PAN rat model was constructed by a single intravenous injection of 100 mg/kg body weight. Renal function and 24hour urinary protein were measured at day 3, 7, 14, 21 after PAN injection. The renal tissue morphology was observed by light and electron microscope. Podocyte apeptosis was evaluated by TUNEL. Protein expressions of nephrin, TGF-β1 and p-Smad2/3 were examined by immunofluoreacence, immunohistochemistry and Western blot, respectively. Results(1)The levels of serum creafinine, BUN and 24-h urinary protein [(20.26±4.87) mg vs (1.01±0.41) mg at day 7, P ＜0.01] were significantly higher and the number of glomerular pedocyte was significantly lower [(10.9±4.2)/glomerular volume vs (31.9±6.2)/glomerular volume at day 14, P＜0.01] in PAN group compared with NC group. T group rats had less urinary protein excretion [(9.95±3.82) mg/24 h, P＜0.01] and more glomerular podocytes compared with PAN group. (2) Distribution of nephrin expression was changed from linear to granular pattern in PAN rats on day 7, nephrin mRNA and protein expressions were markedly decreased(P＜0.01), while the number of apoptotic podocyte was increased in PAN group(P＜0.01). However, higher nephrin expression and less apoptotic podocytes were found in T group (P＜0.01). (3) Compared with NC group, the mRNA and protein expression of TGF-β1 and p-Smad2/3 were higher in PAN group (P＜0.01), while 1,25 (OH)2D3 treatment abrogated PAN-induced changes in the expression of TGF-β1 and p-Smad2/3 (P＜0.01). Conclusions 1,25 (OH)2D3 can significantly suppress PAN-induced podocyte apoptosis and ameliorate proteinnuria. The beneficial effect of 1,25(OH)2D3 on podocyte may contribute to direct suppression of TGF-β signaling.
ABSTRACT
AIM: To explore the role of TGF-?_1 and signaling transduction molecule, Smad4, in the development of glomerulosclerosis. METHODS: Expression levels of TGF-?_1, Smad4, collagen Ⅰ proteins were evaluated by immunohistochemistry in renal biopsies from 38 cases with a spectrum of glomerulonephritis, and compared with 20 normal kidney tissue with image analysis system. After stimulation with TGF-?_1, expressions of endogenous Smad4 and collagen Ⅰ mRNA and proteins and its modulation by TGF?_1 were evaluated by RT-PCR and Western blotting analyses in cultured human mesangial cells. RESULTS: All types of proliferative and sclerotized glomerulonephritis showed an increased expression of TGF-?_1, Smad4 and collagen Ⅰ ompared with the 20 normal kidney tissue in glomerular (P