| Objective:To observe the therapeutic effect and to explore the possible mechanism of the functional component of tea on renal injury of rats induced by5/6nephrectomy associated with hyperuricemia.Methods:1、96healthy female SD rats weighted200±20g were divided into four groups randomly:sham operation group (Sham group),5/6subtotal nephrectomy group (RK group),5/6subtotal nephrectomy and oxonic acid group (RK+OA group), oxonic acid group (OA group),24rats in each group.24-hour urine were collected after a follow-up of4weeks,8weeks,12weeks, respectively, and then8rats were sacrificed in each group for serum and renal histological study.2、120healthy female SD rats weighted200±20g were divided into five groups randomly:sham operation group (Sham group),5/6subtotal nephrectomy group (RK group),5/6subtotal nephrectomy and oxonic acid group (RK+OA group),5/6subtotal nephrectomy and oxonic acid and tea group (RK+OA+Tea group),5/6subtotal nephrectomy and oxonic acid and allopurinol group (RK+OA+AP group),24rats in each group.24-hour urine were collected after a follow-up of4weeks,8weeks,12weeks, respectively, and then8rats were sacrificed in each group for serum and renal histological study.3、24-hour urinary protein content was determined by biurea method. Aotomatic biochemical analyzer was used for the determination of serum uric acid, creatinine, urea nitrogen. HE staining and PAS staining were used for renal histological study. The morphology of afferent arterioles, interstitial microvessel density, the proliferation of tubular epithelial cells and expressing of TGF-β were determined by immunohistochemical method. The apoptosis of tubular epithelial were detected by TUNEL assay. ELISA method was used for detected with serum xanthine oxidase and NADPH oxidase, angiotensin Ⅱ concentration of renal cortex. KLF-5and phosphorylated p38MAPK protein in renal tissue were determined by western blot.Results:1、The24-hour urinary protein content, serum creatinine and urea nitrogen level were higher in RK group at each time point than that in Sham group (P<0.05). Glomerular hyperplasia, hypertrophy and sclerosis, tubular atrophy and dilation, interstitial inflammatory cell infiltration and interstitial fibrosis appeared. The afferent arterioles had a slightly hyperplasia. And the interstitial microvessel density was reduced. The apoptosis index and the expression of TGF-β in tubular epithelial were increased.2、Compared to RK group, the24-hour urinary protein content (exclude that at the time point of12weeks), serum uric acid level, serum creatinine and urea nitrogen level in RK+OA group were much higher at each time point (P<0.05). The renal pathological lesion was more severe in RK+OA group. And the interstitial pathologic lesion scores in RK+OA group was significantly higher than that in RK group at each time point (P<0.05). The afferent arterioles had a significant hyperplasia. And the interstitial microvessel density was reduced significantly. The apoptosis index of tubular epithelial was significantly increased, while the proliferation index was decreased. And the expression of TGF-β in tubular epithelial was significantly increased. The serum uric acid level had a positive correlation with24-hour urinary protein content, serum creatinine level, urea nitrogen level, and the interstitial pathologic lesion scores, respectively in RK+OA group.3、The serum uric acid level, serum creatinine and urea nitrogen level and24-hour urinary protein content in RK+OA+Tea group at each time point were significant lower (P<0.05); the glomerular hyperplasia and interstitial fibrosis, the afferent arterioles hyperplasia and the loss of peritubular capillary were ameliorated significantly; the apoptosis of tubular epithelial were reduced while the proliferation of tubular epithelial were promoted; the expression of TGF-P in tubular epithelial were significantly decreased. Compared to RK+OA+AP group, the indicators of renal injury of rats were improved more significantly in RK+OA+Tea group.4、The serum XO concentration in RK+OA group at each time point was significantly higher than that in RK group; and the serum XO concentration was decreased in RK+OA+Tea group (P<0.05)5、Compared to RK group, the serum NADPH oxidase concentration, the angiotensin II concentration of renal cortex, KLF-5and phosphorylated p38MAPK protein in renal tissue were all significant higher in RK+OA group at each time point.6、The serum NADPH oxidase concentration, the angiotensin II concentration of renal cortex, KLF-5and phosphorylated p38MAPK protein in renal tissue in RK+OA+Tea group at each time point were all significant lower than that in RK+OA group.Conlusion:1、Successfully constructed an animal model characterized with chronic kidney disease associated with hyperuricemia.2、The formula of functional component of tea could significantly ameliorate renal injury of rats caused by5/6subtotal nephrectomy associated with hyperuricemia:significantly lower the serum uric acid level, serum creatinine and urea nitrogen level and24-hour urinary protein content; significantly ameliorate the afferent arterioles hyperplasia and the loss of peritubular capillary; significantly ameliorate the apoptosis of tubular epithelial, and promote the proliferation of tubular epithelial; significantly ameliorate the renal interstitial fibrosis.3、The formula of the functional component of tea was mainly through the following three ways to ameliorate the renal injury of rats caused by5/6subtotal nephrectomy associated with hyperuricemia:①suppressing the serum XO to reduce the production of uric acid, then the serum uric acid level was decreased,②suppressing the NADPH oxidase and reducing the angiotensin Ⅱ to ameliorate oxidative stress, thereby ameliorating the vascular injury caused by hyperuricemia.③inhibiting the activation of RAS and p38MAPK and lowering the expression of KLF-5to ameliorate the vascular smooth muscle cell proliferation caused by hyperuricemia.4、The formula of functional component of tea could be a new choice in therapy of renal injury caused by hyperuricemia. |
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