Ellagic acid, an NF-κB inhibitor, ameliorates renal function in experimental diabetic nephropathy.

Diabetic nephropathy (DN) is a serious complication confronted by diabetic patients. Available data indicate that the development of DN is linked to inflammation. In this context, nuclear factor-kappa B (NF-κB) has received much attention. Ellagic acid (2,3,7,8-tetrahydroxy-chromeno[5,4,3-cde]chromene-5,10-dione), found abundantly in plant extracts and fruits, possesses numerous medicinal properties. We investigated the nephroprotective effects of oral treatment of ellagic acid in high fat diet/low dose streptozotocin (HFD/STZ)-induced type 2 diabetic Wistar albino rats. Ellagic acid treatment for 16weeks post induction of diabetes significantly attenuated renal dysfunction and oxidative stress. Ellagic acid significantly inhibited the renal NF-кB activation. Moreover, ellagic acid significantly lowered renal pathology and suppressed transforming growth factor-beta (TGF-β) and fibronectin expressions in renal tissues. Ellagic acid also significantly reduced the serum levels of pro-inflammatory cytokines, interleukin-1beta (IL-1β), IL-6 and tumor necrosis factor-alpha (TNF-α). In cultured rat NRK 52E proximal tubular epithelial cells, ellagic acid treatment inhibited high glucose-induced activation of NF-κB and pro-inflammatory cytokine synthesis. These results suggest that ellagic acid exhibited renal protective effect in diabetic rats partly through antihyperglycemia which was accompanied by attenuation of inflammatory processes via inhibition of NF-κB pathway.

Ahad A ，Ganai AA ，Mujeeb M ，Siddiqui WA ... -  《-》

Gallic acid ameliorates renal functions by inhibiting the activation of p38 MAPK in experimentally induced type 2 diabetic rats and cultured rat proximal tubular epithelial cells.

Diabetic nephropathy (DN) is one of the leading causes of morbidity and mortality in diabetic patients that accounts for about 40% of deaths in type 2 diabetes. p38 mitogen activated protein kinase (p38 MAPK), a serine-threonine kinase, plays an important role in tissue inflammation and is known to be activated under conditions of oxidative stress and hyperglycemia. The role of p38 MAPK has been demonstrated in DN, and its inhibition has been suggested as an alternative approach in the treatment of DN. In the present study, we investigated the nephroprotective effects of an anti-inflammatory phenolic compound, gallic acid (GA, 3,4,5-trihydroxybenzoic acid), in high fat diet/streptozotocin (HFD/STZ) induce type 2 diabetic wistar albino rats. GA (25 mg/kgbw and 50 mg/kgbw, p.o.) treatment for 16 weeks post induction of diabetes led to a significant reduction in the levels of blood glucose, HbA1c, serum creatinine, blood urea nitrogen and proteinuria as well as a significant reduction in the levels of creatinine clearance. GA significantly inhibited the renal p38 MAPK and nuclear factor kappa B (N-κB) activation as well as significantly reduced the levels of renal transforming growth factor beta (TGF-β) and fibronectin. Treatment with GA resulted in a significant reduction in the serum levels of proinflammatory cytokines viz. interleukin 1 beta (IL-1β), IL-6 and tumor necrosis factor alpha (TNF-α). Moreover, GA significantly lowered renal pathology and attenuated renal oxidative stress. In cultured rat NRK 52E proximal tubular epithelial cells, GA treatment inhibited high glucose induced activation of p38 MAPK and NF-κB as well as suppressed proinflammatory cytokine synthesis. The results of the present study provide in vivo and in vitro evidences that the p38 MAPK pathway plays an important role in the pathogenesis of DN, and GA attenuates the p38 MAPK-mediated renal dysfunction in HFD/STZ induced type 2 diabetic rats.

Ahad A ，Ahsan H ，Mujeeb M ，Siddiqui WA ... -  《-》

Chrysin, an anti-inflammatory molecule, abrogates renal dysfunction in type 2 diabetic rats.

Diabetic nepropathy (DN) is considered as the leading cause of end-stage renal disease (ESRD) worldwide, but the current available treatments are limited. Recent experimental evidences support the role of chronic microinflammation in the development of DN. Therefore, the tumor necrosis factor-alpha (TNF-α) pathway has emerged as a new therapeutic target for the treatment of DN. We investigated the nephroprotective effects of chrysin (5, 7-dihydroxyflavone) in a high fat diet/streptozotocin (HFD/STZ)-induced type 2 diabetic Wistar albino rat model. Chrysin is a potent anti-inflammatory compound that is abundantly found in plant extracts, honey and bee propolis. The treatment with chrysin for 16weeks post induction of diabetes significantly abrogated renal dysfunction and oxidative stress. Chrysin treatment considerably reduced renal TNF-α expression and inhibited the nuclear transcription factor-kappa B (NF-кB) activation. Furthermore, chrysin treatment improved renal pathology and suppressed transforming growth factor-beta (TGF-β), fibronectin and collagen-IV protein expressions in renal tissues. Chrysin also significantly reduced the serum levels of pro-inflammatory cytokines, interleukin-1beta (IL-1β) and IL-6. Moreover, there were no appreciable differences in fasting blood glucose and serum insulin levels between the chrysin treated groups compared to the HFD/STZ-treated group. Hence, our results suggest that chrysin prevents the development of DN in HFD/STZ-induced type 2 diabetic rats through anti-inflammatory effects in the kidney by specifically targeting the TNF-α pathway.

Ahad A ，Ganai AA ，Mujeeb M ，Siddiqui WA ... -  《-》

BAY 11-7082 ameliorates diabetic nephropathy by attenuating hyperglycemia-mediated oxidative stress and renal inflammation via NF-κB pathway.

Diabetic nephropathy is a serious microvascular complication for patients associated with diabetes mellitus. Recent studies have suggested that NF-κB is the main transcription factor for the inflammatory response mediated progression of diabetic nephropathy. Hence, the present study is hypothesized to explore the renoprotective nature of BAY 11-7082 an IκB phosphorylation inhibitor on Streptozotocin (STZ) induced diabetic nephropathy in Sprague-Dawley (SD) rats. Male SD rats were divided into five groups, group I sham control, group II drug control, group III diabetic control (STZ 50mg/kg), group IV and V are test drug groups to which a single dose of STZ 50mg/kg was injected initially and later received BAY 11-7082 1mg/kg and 3mg/kg, respectively from 5th to 8th week. Eight weeks after STZ injection, diabetic rats exhibited significant renal dysfunction, as evidenced by reduced creatinine clearance, increased blood glucose, urea nitrogen and creatinine, which were reversed to near normal by BAY 11-7082. BAY 11-7082 treated rats showed significant improvement in the decreased enzymatic antioxidant SOD, non-enzymatic antioxidant GSH levels, and elevated lipid peroxidation and nitric oxide levels as observed in the diabetic rats. BAY 11-7082 treatment was found to significantly recover kidney histological architecture in the diabetic rats. Altered levels of inflammatory cytokines like TNF-α, IL-1β, IL-6 and nuclear transcriptional factor subunit NF-κB p65 were reverted to the normal level upon treatment with BAY 11-7082. Our results suggest that by limiting the activation of NF-κB, thereby reducing the expression of inflammatory cytokines and by inhibiting the oxidative damage BAY 11-7082 protect the rats against diabetic nephropathy.

Kolati SR ，Kasala ER ，Bodduluru LN ，Mahareddy JR ，Uppulapu SK ，Gogoi R ，Barua CC ，Lahkar M ... -  《-》

Apigenin ameliorates streptozotocin-induced diabetic nephropathy in rats via MAPK-NF-κB-TNF-α and TGF-β1-MAPK-fibronectin pathways.

Diabetic nephropathy (DN), a microvascular complication of diabetes, has emerged as an important health problem worldwide. There is strong evidence to suggest that oxidative stress, inflammation, and fibrosis play a pivotal role in the progression of DN. Apigenin has been shown to possess antioxidant, anti-inflammatory, antiapoptotic, antifibrotic, as well as antidiabetic properties. Hence, we evaluated whether apigenin halts the development and progression of DN in streptozotocin (STZ)-induced diabetic rats. Male albino Wistar rats were divided into control, diabetic control, and apigenin treatment groups (5-20 mg/kg po, respectively), apigenin per se (20 mg/kg po), and ramipril treatment group (2 mg/kg po). A single injection of STZ (55 mg/kg ip) was administered to all of the groups except control and per se groups to induce type 1 diabetes mellitus. Rats with fasting blood glucose >250 mg/dl were included in the study and randomized to different groups. Thereafter, the protocol was continued for 8 mo in all of the groups. Apigenin (20 mg/kg) treatment attenuated renal dysfunction, oxidative stress, and fibrosis (decreased transforming growth factor-β1, fibronectin, and type IV collagen) in the diabetic rats. It also significantly prevented MAPK activation, which inhibited inflammation (reduced TNF-α, IL-6, and NF-κB expression) and apoptosis (increased expression of Bcl-2 and decreased Bax and caspase-3). Furthermore, histopathological examination demonstrated reduced inflammation, collagen deposition, and glomerulosclerosis in the renal tissue. In addition, all of these changes were comparable with those produced by ramipril. Hence, apigenin ameliorated renal damage due to DN by suppressing oxidative stress and fibrosis and by inhibiting MAPK pathway.

Malik S ，Suchal K ，Khan SI ，Bhatia J ，Kishore K ，Dinda AK ，Arya DS ... -  《-》