Cardiac disturbances and changes in tissue cytokine levels in mice fed with a high-refined carbohydrate diet.

AIMS: The consumption of highly refined carbohydrates increases systemic inflammatory markers, but its potential to exert direct myocardial inflammation is uncertain. Herein, we addressed the impact of a high-refined carbohydrate (HC) diet on mice heart and local inflammation over time. MAIN METHODS: BALB/c mice were fed with a standard chow (control) or an isocaloric HC diet for 2, 4, or 8 weeks (HC groups), in which the morphometry of heart sections and contractile analyses by invasive catheterization and Langendorff-perfused hearts were assessed. Cytokines levels by ELISA, matrix metalloproteinase (MMP) activity by zymography, in situ reactive oxygen species (ROS) staining and lipid peroxidation-induced TBARS levels, were also determined. KEY FINDINGS: HC diet fed mice displayed left ventricular hypertrophy and interstitial fibrosis in all times analyzed, which was confirmed by echocardiographic analyses of 8HC group. Impaired contractility indices of HC groups were observed by left ventricular catheterization, whereas ex vivo and in vitro indices of contraction under isoprenaline-stimulation were higher in HC-fed mice compared with controls. Peak levels of TNF-α, TGF-ß, ROS, TBARS, and MMP-2 occur independently of HC diet time. However, a long-lasting local reduction of the anti-inflammatory cytokine IL-10 was found, which was linearly correlated to the decline of systolic function in vivo. SIGNIFICANCE: Altogether, the results indicate that short-term consumption of HC diet negatively impacts the balance of anti-inflammatory defenses and proinflammatory/profibrotic mediators in the heart, which can contribute to HC diet-induced morphofunctional cardiac alterations.

Morphological study of apoptosis in granulosa cells and ovulation in a model of atresia in rat preovulatory follicles.

SummaryPrevious studies have established a model of atresia in preovulatory follicles after stimulation of immature rats with equine chorionic gonadotropin (eCG). This gonadotropin recruits a follicular pool and the deprivation of preovulatory luteinizing hormone (LH) surge induces the atresia in preovulatory follicles. The present study investigated the occurrence of ovulation and provided some morphological features of granulosa cell (GC) apoptosis of atretic follicles at 0, 48, 72 and 120 h after eCG stimulation. Histological sections of ovaries from untreated animals (0 h) showed primordial, primary, secondary and early antral follicles. After 48 h ovaries showed large antral follicles. Preovulatory follicles were observed at 72 h, and two out of five rats displayed cumulus-oocyte complexes (COCs) in the oviducts. All animals exhibited corpora lutea after 120 h. We observed increased estradiol (E2) levels 48 h after eCG treatment that might trigger an endogenous preovulatory gonadotropin surge. Higher progesterone (P4) level, which is the hallmark of a functional corpus luteum, was observed at 120 h. Atresia in secondary and antral follicles was observed by pyknotic granulosa cell nuclei in histology and positive immunolabelling for cleaved caspase 3. We also observed macrophages in secondary and antral follicles in atresia. Transmission electron microscopy revealed GCs with compacted chromatin against the nuclear envelope, nuclear fragmentation, cell shrinkage and fragmentation. No preovulatory follicles showed apoptosis of GCs. In conclusion, our results suggested the occurrence of an endogenous gonadotropin surge, promoting ovulation and preventing atresia of preovulatory follicles.