Phytolacca americana inhibits the high glucose-induced mesangial proliferation via suppressing extracellular matrix accumulation and TGF-beta production

NAD+ Protects against Hyperlipidemia-induced Kidney Injury in Apolipoprotein E-deficient Mice

Background: Hyperlipidemia is an independent risk factor for kidney injury. Several studies have shown that nicotinamide adenine dinucleotide (NAD+) is an important coenzyme involved in normal body metabolism. Therefore, this study aimed to investigate the possible protective effects of NAD+ against hyperlipidemia-induced kidney injury in apolipoprotein Edeficient (ApoE-/-) mice.

Methods: Twenty-five eight-week-old male ApoE-/- mice were randomly assigned into four groups: normal diet (ND), ND supplemented with NAD+ (ND+NAD+), high-fat diet (HFD), and HFD supplemented with NAD+ (HFD+NAD+). The mice were subjected to their respective diets for a duration of 16 weeks. Blood samples were obtained from the inferior vena cava, collected in serum tubes, and stored at -80°C until use. Kidney tissues was fixed in 10% formalin and then embedded in paraffin for histological evaluation. The remainder of the kidney tissues was snapfrozen in liquid nitrogen for Western blot analysis.

Results: Metabolic parameters (total cholesterol, triglycerides, low-density lipoprotein-cholesterol, creatinine, and blood urea nitrogen) were significantly higher in the HFD group compared to the other groups. Histological analysis revealed prominent pathological manifestations in the kidneys of the HFD group. The HFD+NAD+ group showed increased levels of oxidative stress markers (NRF2 and SOD2) and decreased levels of NOX4 compared to the HFD group. Furthermore, the HFD group exhibited higher levels of TGF-β, Smad3, Collagen I, Collagen III, Bax, and Bak compared to the other groups. NAD+ supplementation in the HFD+NAD+ group significantly increased the levels of SIRT3, HO-1, Bcl-2, and Bcl-xL compared to the HFD group. Additionally, NF-κB protein expression was higher in the HFD group than in the HFD+NAD+ group.

Conclusion: These findings demonstrated that NAD+ may hold potential as a clinical treatment for kidney injury caused by hyperlipidemia.

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Exercise reduces hyperlipidemia-induced kidney damage in apolipoprotein E-deficient mice

Hyperlipidemia is a risk factor of kidney damage that can lead to chronic kidney disease. Studies have shown that exercise reduces kidney damage; however, the specific mechanisms underlying the protective effects of exercise remain unclear. For 12 weeks, 8-week-old male apolipoprotein E-deficient (ApoE^-/-) mice were randomly divided into four treatment groups (n=7/group) as follows: Mice fed a normal diet (ND group); mice fed a ND and exercised (ND + E group); mice fed a high-fat diet (HD group); and mice fed a HD and exercised (HD + E group). Exercise training consisted of swimming for 40 min, 5 days/week. Metabolic parameters, such as low-density lipoprotein-cholesterol, total cholesterol and creatinine levels were higher in the ApoE^-/- HD mice compared with those in the ApoE^-/- HD + E mice. Serum levels of glutathione peroxidase and superoxide dismutase were significantly decreased in the HD group compared with those in the HD + E group. Significant pathological changes were observed in the HD + E group compared with in the HD group. Immunohistochemistry and immunoblotting revealed increased levels of oxidative stress (nuclear factor erythroid-2-related factor 2) and fibrosis (Smad3 and TGF-β) markers in the ApoE^-/- HD group; however, the expression levels of these markers were significantly decreased in the ApoE^-/- HD + E group. Furthermore, NF-κB expression in the HD + E group was significantly lower compared with that in the HD group. These results suggested that exercise may exert protective effects against kidney damage caused by hyperlipidemia.

Amelioration of Diabetes-Induced Diabetic Nephropathy by Aloe vera: Implication of Oxidative Stress and Hyperlipidemia

This study investigated the effect of Aloe vera in diabetes-induced nephropathy in rats. As diabetes-associated hyperlipidemia and oxidative stress have been implicated in the pathogenesis of diabetic nephropathy, we evaluated the protective effect of whole leaf extract of Aloe vera on the basis of its hypolipidemic and antioxidative property. Aloe vera (300 mg/kg orally) has been noted to possess renoprotective effect in experimental diabetic nephropathy. However, its mechanism is not fully understood. Rats were administered streptozotocin (STZ) (55 mg/kg intraperitoneally once) to induce experimental diabetes mellitus. The development of diabetic nephropathy was assessed biochemically and histologically. In addition, the diabetes-induced lipid profile and renal oxidative stress were assessed. The single administration of STZ produced diabetes, which induced renal oxidative stress, altered the lipid profile, and subsequently produced nephropathy in eight weeks by increasing serum creatinine, blood urea nitrogen, proteinuria, and glomerular damage. Treatment with Aloe vera (300 mg/kg/day orally) was noted to be more effective against the diabetes-induced nephropathy and renal oxidative stress as compared to lisinopril (1 mg/kg/day orally), a reference agent. It may be concluded that diabetes-induced oxidative stress and lipid alterations may be accountable for the induction of nephropathy in diabetic rats. The treatment with Aloe vera (300 mg/kg/day orally) may have prevented the development of diabetes-induced nephropathy by reducing lipid alteration, decreasing renal oxidative stress, and providing direct renoprotective action.