Evaluation of the Therapeutic Effects of Protocatechuic Aldehyde in Diabetic Nephropathy.

Diabetic nephropathy (DN) is one of the most severe chronic kidney diseases in diabetes and is the main cause of end-stage renal disease (ESRD). Protocatechuic aldehyde (PCA) is a natural product with a variety of effects on pulmonary fibrosis. In this study, we examined the effects of PCA in C57BL/KS db/db male mice. Kidney morphology, renal function indicators, and Western blot, immunohistochemistry, and hematoxylin and eosin (H&E) staining data were analyzed. The results revealed that treatment with PCA could reduce diabetic-induced renal dysfunction, as indicated by the urine albumin-to-creatinine ratio (db/m: 120.1 ± 46.1µg/mg, db/db: 453.8 ± 78.7 µg/mg, db/db + 30 mg/kg PCA: 196.6 ± 52.9 µg/mg, db/db + 60 mg/kg PCA: 163.3 ± 24.6 µg/mg, p < 0.001). However, PCA did not decrease body weight, fasting plasma glucose, or food and water intake in db/db mice. H&E staining data revealed that PCA reduced glomerular size in db/db mice (db/m: 3506.3 ± 789.3 µm2, db/db: 6538.5 ± 1818.6 µm2, db/db + 30 mg/kg PCA: 4916.9 ± 1149.6 µm2, db/db + 60 mg/kg PCA: 4160.4 ± 1186.5 µm2p < 0.001). Western blot and immunohistochemistry staining indicated that PCA restored the normal levels of diabetes-induced fibrosis markers, such as transforming growth factor-beta (TGF-ß) and type IV collagen. Similar results were observed for epithelial-mesenchymal transition-related markers, including fibronectin, E-cadherin, and α-smooth muscle actin (α-SMA). PCA also decreased oxidative stress and inflammation in the kidney of db/db mice. This research provides a foundation for using PCA as an alternative therapy for DN in the future.

Lutein attenuates oxidative stress markers and ameliorates glucose homeostasis through polyol pathway in heart and kidney of STZ-induced hyperglycemic rat model.

PURPOSE: Lutein's role on chronic hyperglycemia-induced oxidative stress and associated glucose homeostasis in heart and kidney is limited. Purpose of the study is to investigate the effect of lutein on cardiac and renal polyol pathway enzymes and oxidative stress markers under hyperglycemia-induced oxidative stress condition using streptozotocin (STZ)-injected rat model. METHODS: STZ-induced hyperglycemic (fasting blood glucose ≥11 mM) male Wistar rats were divided into two groups (n = 11/group). Group 1 received micellar lutein (39 nmol/day/rat) and group 2 (negative control) received micelle without lutein for 8 weeks. A separate group (no STZ injected) served as a positive control (n = 11/group). Oral glucose tolerance test (OGTT), biweekly urine glucose and activities of aldose reductase (AR) and sorbitol dehydrogenase (SDH) enzymes were assessed. Activities of antioxidant enzymes and antioxidant level were also evaluated. RESULTS: Lutein-administered hyperglycemic rats showed better glucose tolerance as evidenced with OGTT and biweekly urine glucose when compared to negative control. Activities of AR and SDH were decreased in heart and kidney of lutein-fed hyperglycemic rats. Also, they had significantly (p < 0.05) decreased malondialdehyde levels (66, 34, and 33 %) and increased reduced glutathione level (81, 18 and 92 %) in serum, heart and kidney, respectively. Altered antioxidant enzyme activities such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione transferase were also affected in serum, heart and kidney of lutein-fed diabetic group. CONCLUSION: Lutein prevented cardiac and renal injury in STZ-induced hyperglycemic rats due to potential amelioration of altered activities in polyol pathway and oxidative stress markers.

Proteomic analysis of urine in rats chronically exposed to fluoride.

Urine is an ideal source of materials to search for potential disease-related biomarkers as it is produced by the affected tissues and can be easily obtained by noninvasive methods. 2-DE-based proteomic approach was used to better understand the molecular mechanisms of injury induced by fluoride (F(-)) and define potential biomarkers of dental fluorosis. Three groups of weanling male Wistar rats were treated with drinking water containing 0 (control), 5, or 50 ppm F(-) for 60 days (n = 15/group). During the experimental period, the animals were kept individually in metabolic cages, to analyze the water and food consumption, as well as fecal and urinary F(-) excretion. Urinary proteome profiles were examined using 2-DE and Colloidal Coomassie Brilliant Blue staining. A dose-response regarding F(-) intake and excretion was detected. Quantitative intensity analysis revealed 8, 11, and 8 significantly altered proteins between control vs. 5 ppm F(-), control vs. 50 ppm F(-) and 5 ppm F(-) vs. 50 ppm F(-) groups, respectively. Two proteins regulated by androgens (androgen-regulated 20-KDa protein and α-2µ-globulin) and one related to detoxification (aflatoxin-B1-aldehyde-reductase) were identified by MALDI-TOF-TOF MS/MS. Thus, proteomic analysis can help to better understand the mechanisms underlying F(-) toxicity, even in low doses.