Effects of grape seed proanthocyanidin B2 pretreatment on oxidative stress and renal tubular epithelial cell apoptosis after renal ischemia reperfusion in mice

Effects of grape seed-derived proanthocyanidin B2 pretreatment on oxidative stress, endoplasmic reticulum stress and apoptosis of renal tubular epithelial cells in renal ischemia-reperfusion injury model of mice

PURPOSE

To investigate the effect of grape seed-derived proanthocyanidin B2 (GSPB2) pretreatment on acute renal ischemia-reperfusion injury model of mice.

METHODS

50 mice were divided into 5 groups: Sham group: mice were treated with right nephrectomy. GSPB2 group: GSPB2 was injected intraperitoneally 45 min before right nephrectomy. IRI group: right kidney was resected and the left renal arteriovenous vessel was blocked for 45 min. GSPB2 + IRI group: GSPB2 was intraperitoneally injected 45 min before IRI established. GSPB2 + BRU + IRI group: GSPB2 and brusatol (BRU) were injected intraperitoneally 45 min before IRI established. Creatinine and urea nitrogen of mice were detected, and the kidney morphology and pathological changes of each group were detected by HE staining, PAS staining and transmission electron microscopy. Expressions of Nrf2, HO-1, GRP78, CHOP, and cleaved-caspase3 were detected by immunofluorescence staining and western blotting.

RESULTS

Morphology and mitochondrial damages of kidney in GSPB2 + IRI group were significantly alleviated than those in IRI group. Expression levels of Nrf2 and HO-1 were significantly higher in GSPB2 + IRI group than those in IRI group. Expression levels of GRP78, CHOP and cleaved-caspase3 were significantly lower in GSPB2 + IRI group than those in IRI group. However, compared to GSPB2 + IRI group, protective effects of GSPB2 pretreatment were weakened in GSPB2 + BRU + IRI group.

CONCLUSIONS

GSPB2 pretreatment could alleviate oxidative stress damage and reduce apoptosis of renal tubular epithelial cells, which might be related to activating the antioxidant system, up-regulating the expression of Nrf2 and HO-1, inhibiting the expressions of GRP78, CHOP and cleaved-caspase3. However, the protective effect could be reversed by brusatol.

Grape Seed Extract and Urolithiasis: Protection Against Oxidative Stress and Inflammation

Background

Grape seed extract (GSE) has demonstrated various pharmacological actions. Urolithiasis is the occurrence of calculus in the renal system. The present study evaluated the anti-urolithic effect of GSE on ethylene glycol (EG) and ammonium chloride (AC)-induced experimental urolithiasis in rats.

Materials and Methods

Rats were assigned into six groups; Normal control and Normal + GSE, in which rats received standard drinking water and GSE orally daily, respectively; Urolithiatic animals received EG with AC in drinking water for 28 days; Urolithiatic animals + GSE, in which rats were administered EG with AC in drinking water and GSE 100 and 200 mg/kg orally; and Urolithiatic + cystone, where rats received EG with AC in drinking water and 750 g/kg of cystone as a standard drug orally.

Results

Urolithiatic animals showed a significant decrease in excreted magnesium and citrate and antioxidant enzymes, whereas they exhibited amplified oxalate crystal numbers, urinary excreted calcium, phosphate, oxalate ions, uric acid, intensified renal function parameters, lipid peroxidation, and inflammatory mediators. Management with GSE and cystone significantly augmented urolithiasis inhibitors (excreted magnesium and citrate) and amplified the antioxidant enzymes’ activities. GSE reduced oxalate crystal numbers and urolithiasis promoters, including excreted calcium, oxalate, phosphate, and uric acid excretion, lessened renal function parameters, and declined lipid peroxidation and the inflammatory mediators.

Conclusion

GSE could protect against EG-induced renal stones as evidenced by mitigated kidney dysfunction, histological alterations, and oxalate crystal formation. This action may be related to the antioxidant as well as anti-inflammatory activities of the extracts.

Nrf-2 as a therapeutic target in acute kidney injury

Multifaceted cellular pathways exhibit a crucial role in the preservation of homeostasis at the molecular, cellular, and organism levels. One of the most important of these protective cascades is Nuclear factor E2-related factor (Nrf-2) that regulates the expression of several genes responsible for cellular detoxification, antioxidant function, anti-inflammation, drug/xenobiotic transportation, and stress-related factors. A growing body of evidence provides information regarding the protective role of Nrf-2 against a number of kidney diseases. Acute kidney injury (AKI) is a substantial clinical problem that causes a huge social burden. In the kidneys, Nrf-2 exerts a dynamic role in improving the injury triggered by inflammation and oxidative stress. Understanding of the exact molecular mechanisms underlying AKI is vital in order to determine the equilibrium between renal adaptation and malfunction and thus reduce disease progression. This review highlights the role of Nrf-2 targeting against AKI and provides evidence that targeting Nrf-2 to prevail oxidative damage and its consequences might exhibit protective effects in kidney diseases.