Protective effect of ferulic acid on STZ-induced diabetic nephropathy in rats.

Diabetic nephropathy (DN) is a major and severe complication of diabetes mellitus. Ferulic acid (FA), a phenolic compound widespread in fruits and plants, displays a variety of pharmacological activities including regulating blood glucose and lipids, anti-oxidation, anti-inflammation and anti-fibrosis. The study was aimed to investigate the renal protective effects of FA on diabetic rats and elucidate the underlying mechanisms. FA (100 mg kg-1, i.g., once a day) was administered to DN rats for 8 weeks. The organ coefficient of kidneys was calculated. Levels of UP, BUN, Cr, FBG, TC and TG in serum were measured. Activities of SOD, CAT and GPx and the content of MDA in renal tissues were assayed. Pathological changes in renal tissues were observed by HE staining, PAS staining, PASM staining, Masson staining and transmission electron microscopy. p-NF-κB p65, TNF-α, TGF-ß1, collagen IV, nephrin and podocin protein expressed in renal tissues were determined by immunohistochemistry and western blotting. Results showed that FA significantly improved the kidney organ coefficient, decreased the UP, BUN, Cr, FBG, TC and TG levels in serum, increased SOD, CAT and GPx activities, reduced MDA content in renal tissues and alleviated pathological injury of the renal tissues. What's more, long-term treatment with FA considerably down-regulated the expressions of p-NF-κB p65, TNF-α, TGF-ß1 and collagen IV proteins, and up-regulated the expressions of nephrin and podocin proteins in renal tissues. FA could be a renoprotective agent by attenuating oxidative stress, inflammation, and fibrosis, as well as improving podocyte injury in STZ-induced DN rats.

[Selection of modeling time for type 2 diabetes mellitus mouse].

OBJECTIVE: To analyze the changes of blood biochemical index and the pathological changes of myocardium and kidney in type 2 diabetic mouse at different time points, which can provide the basis for the selection of type 2 diabetic modeling time for later research. METHODS: After 6 weeks of feeding with high-fat diet, 24 healthy male ICR mice were injected with streptozocin (STZ, 30 mg/kg) intraperitoneally for 5 days to establish diabetic models. After 9 days, a random blood glucose ≥ 11.1 mmol / L was measured as diabetic mice. 4, 6 and 8 weeks after successfully preparing the diabetic mouse, 8 diabetic mice (a group)would be sacrificed each time. Then the biochemical and pathological conditions were analyzed: ① the indexes of heart and kidney were calculated. ②the serum levels of creatine kinase (CK), lactate dehydrogenase (LDH), creatinine (Cr) and blood urine nitrogen (BUN) were determined. ③ Histopathological changes of myocardium and renal tissues were observed by hematoxylin and eosin (HE) staining. Masson staining was used to observe the fibrosis of myocardium. PAS staining was adopted to observe the pathological changes of renal tissue. In addition, 8 ICR male mice were taken as the control group. RESULTS: At the 4th, 6th and 8th week, cardiac organ coefficient, the values of LDH and CK were all increased compared with the control group. Cardiomyocyte hypertrophy and myocardial fibrosis could be observed. Renal organ coefficient, the values of Cr and BUN were increased. Glomerular hypertrophy, basement membrane thickening and atrophy could be perceived. CONCLUSION: At the 6th week, related biochemical and pathological changes in diabetic mice were comparatively obvious and breeding time was relatively short. Thus, 6 weeks after the preparation of the diabetic mice would be the optimal time for type 2 diabetes mellitus modeling, proper for inventions of drugs and other research purposes including pathology, physiology, biochemistry, etc.

[Effect of ursolic acid on cardiomyopathy of mice with diabetes and its mechanism].

OBJECTIVE: To study the effect of ursolic acid on cardiomyopathy in mice with diabetes induced by high-fat diet combined with low dose streptozotocin, and to explore its possible mechanism. METHODS: Thirty male ICR mice were randomly divided into control group (n=10) and moulding group (n=20), the mice in the two groups were fed with regular diet and high-fat diet respectively for 6 weeks, and then the mice in the moulding group were injected with streptozotocin (30 mg/kg) for 5 successive days to induce diabetes mellitus (DM). Fasting blood glucose (FBG) was measured after 9 days. Mice with FBG over 11.1 mmol/L were regarded as DM. Twenty DM mice were randomly divided into model group and ursolic acid group (n=10). Mice in each group were continuously administrated ursolic acid (100 mg/kg) or corresponding solvent intragastrically for 8 weeks. After that, FBG was measured, body weight (BW), heart weight and left ventricular weight were weighed in order to calculate the heart mass index (HMI) and left ventricular mass index (LVMI). Levels of creatine kinase (CK), lactate dehydrogenase (LDH) in serum and the level of superoxide dismutase (SOD), malondialdehyde (MDA) in myocardial tissue were detected. HE staining was used to observe pathological changes of myocardial tissue. Immunohistochemistry was employed to determine the expression of NOD-like receptor protein 3 (NLRP3) and interleukin 1ß (IL-1ß). RESULTS: Compared with the control group, HMI, LVMI were apparently enlarged, levels of FBG, CK, LDH in serum and MDA in myocardial tissue were extremely increased, while the activity of SOD in myocardial tissue were extraordinary decreased in diabetic group. HE staining of myocardium showed that arrangement disorder of myocardial fibers, edema and hypertrophy in myocardial cell, as well as inflammatory cell infiltration in model group. Immunohistochemistry showed that the expression of NLRP3 and IL-1ß in myocardial tissue increased obviously in model group, the above changes inursolic acid group were significantly ameliorated. CONCLUSIONS: Ursolic acid has a obvious protective effect on myocardial injury in mice with diabetes induced by high-fat diet combined with low dose streptozotocin, and its mechanism may be associated with inhibiting NLRP3 inflammasome activation, reducing IL-1ß generation and alleviating myocardial inflammatory injury.

Prevalence and spectrum of GATA4 mutations associated with sporadic dilated cardiomyopathy.

Dilated cardiomyopathy (DCM) is the most frequent type of primary myocardial disorder responsible for substantial morbidity and mortality. DCM is the third most common cause of heart failure and the most common reason for heart transplantation. A recent study has implicated GATA4 mutation in the pathogenesis of familial DCM. However, the prevalence and spectrum of GATA4 mutations associated with sporadic DCM remain unclear. In this study, the coding exons and exon-intron boundaries of the GATA4 gene, which encodes a cardiac transcription factor crucial for normal cardiogenesis, were sequenced in 220 unrelated patients with sporadic DCM. A total of 200 unrelated ethnically-matched healthy individuals used as controls were genotyped. The functional characteristics of the mutant GATA4 were assayed in contrast to its wild-type counterpart using a luciferase reporter assay system. As a result, 3 novel heterozygous GATA4 mutations, p.V39L, p.P226Q and p.T279S, were identified in 3 unrelated patients with sporadic DCM, with a mutational prevalence of approximately 1.36%. The missense mutations were absent in 400 control chromosomes and the altered amino acids were completely conserved evolutionarily across species. Functional analysis showed that the GATA4 mutants were consistently associated with significantly decreased transcriptional activity and markedly reduced the synergistic activation between GATA4 and NKX2-5. This study firstly links GATA4 mutations to increased susceptibility to sporadic DCM and provides novel insight into the molecular etiology underlying DCM, suggesting the potential implications for the early prophylaxis and allele-specific treatment of this common form of cardiomyopathy.