| Objective: The purpose of this study was to explore the effect of pyridoxamine and telmisartan on primary hypertensive damage of tubular epithelial cells by animal model of spontaneously hypertensive rats (SHR). The preliminary mechanism was also studied in vitro cell culture of human renal tubular epithelial cells (HK-2).Methods: 1.Forty-eight SHR (22-weeks old, male) as the experimental hypertension group were randomly divided into hypertension control (HC) group were received 2ml H20 everyday. Telmisartan (T) group were received telmisartan 6mg/kg in 2ml H20 everyday. Rats in pyridoxamine group (P group) were received pyridoxamine 200mg/kg in 2ml H20 everyday . Rats in combination therapy TP group were received telmisartan 6mg/kg and pyridoxamine 200mg/kg in 2ml H20 everyday. Thirteen Wistar-Kyoto rats(22-weeks old, male)was the normal control(NC) group were received 2ml H20 each day. After 16 weeks of intervenetion, the 24-hour urinary albumin was measured. The pathological examination of renal tubular epithelial and interstitial cells was detected by histology hematoxylin-eosin staining, Masson staining and transmission electron microscopy. 2.Cultured HK-2 cells were divided into HK-2 normal control, angiotensinⅡ(10-6mol/l) control (AngⅡ) group, telmisartan(10-6mol/l) group(T group), 1mmol/L pyridoxamine group(1mmol/L P group), 10 mmol/L pyridoxamine group (10mmol/L P group) and T(10-6mol/l) + P(10mmol/L) group. Methyl thiazolyl tetrazolium (MTT) was used for measuring of cell proliferation. Reactive oxygen species (ROS) generation was detected by flow cytometry. Real-time quantitative PCR was performed to measure the mRNA expression of transforming growth factor-β1(TGF-β1) and receptor for advanced glycation end-products (RAGE). Results:1. Compared with those in HC group, rats in T and TP group have lower systolic blood pressure and urinary albumin excretion rate (P <0.05). Rats in P group have lower urinary albumin excretion rate, with unchanged systolic blood pressure (P> 0.05). There was no significantly difference of serum creatinine and blood urea nitrogen among five groups (P> 0.05).2. The morphological changes were improved in T group, P group and TP group, compared with those changes of tubulular atrophy, interstitial infiltration of inflammatory cells and fibrosis in HC group.3. Proliferation of HK-2 was inhibited in AngⅡ(P<0.05), 10mmol/L P group and TP group(P<0.01) after both 24h and 48h intervention. Synergy of inhibition was showed in TP group after 48h intervention (P <0.01).4. ROS was reduced in 1mmol/L P group, 10mmol/L P group and TP group(P<0.01).There was no statistically difference among the three groups (P >0.05).5. Compared with the AngⅡgroup, mRNA expression of RAGE and TGF-β1were decreased in T, P and TP group (P <0.05). Synergy decreased of TGF-β1 expression was showed in TP group(P <0.01).Conclusion: In vivo telmisartan and/or pyridoxamine may improve the morphological changes of tubular epithelial cells. In vitro, telmisartan or pyridoxamine significantly improved oxidative stress and reduced both mRNA expression of RAGE and TGF-β1. Synergy were shown in the TGF-β1 reduction and inhibion of cell proliferation. Pyridoxamine was showed stronger inhibition effects on oxidative stress and cell proliferation. |
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