Methylene blue reduces IL-1β levels by enhancing ERK1/2 and AKT phosphorylation to improve diabetic retinopathy in rats / 细胞与分子免疫学杂志

Objective To investigate the neuroprotective effect of methylene blue on diabetic retinopathy in rats. Methods Thirty SD rats were randomly divided into blank, control and experimental groups. The control and experimental groups were induced with diabetes by streptozotocin (STZ) intraperitoneal injection. After 6 weeks of successful modeling, the experimental group received intravitreal injection of methylene blue at a dose of [0.2 mg/(kg.d)], while the control group received an equal amount of dimethyl sulfoxide (DMSO) intravitreal injection, both continuously injected for 7 days. ELISA was used to detect the levels of retinal superoxide dismutase (SOD), 8-iso-prostaglandin F2alpha (iPF2α) and interleukin-1β (IL-1β) in rats. Western blot analysis was used to detect the expression of retinal extracellular signal-regulated kinase 1/2 phosphorylation (p-ERK1/2) and phosphorylated protein kinase B (p-AKT), and PAS staining was used to detect retinal morphological changes. Results Compared with the blank group rats, the retinal SOD activity in the control and experimental group rats was significantly reduced. iPF2α, IL-1β and p-ERK1/2 level increased, while p-AKT level decreased. Compared with the control group, the SOD activity of the experimental group rats increased. iPF2α and IL-1β level went down, while p-ERK1/2 and p-AKT level went up significantly. The overall thickness of the retinal layer and the number of retinal ganglion cells were significantly reduced. Conclusion Methylene blue improves diabetic retinopathy in rats by reducing retinal oxidative stress and enhancing ERK1/2 and AKT phosphorylation.

A study on biventricular myocardial strain characteristics of amateur marathon runners based on cardiac MR feature tracking technique / 中华放射学杂志

Objective:To investigate the changes of biventricular myocardial strain in amateur marathon runners using the cardiac MR feature tracking (CMR-FT) technique.Methods:Forty-one amateur marathon runners (marathon exercise group) and 20 age-matched healthy volunteers (control group) were recruited according to the inclusion criteria. After the kinematic parameters were obtained, all subjects underwent a CMR cine sequence imaging. The CMR images were post-processed using CVI42 software. The biventricular function parameters including end-diastole/end-systolic volume (EDV/ESV), end-diastole/end-systolic volume index (EDVI/ESVI), end-diastole/end-systolic myocardial mass (MMD/MMS), end-diastole/end-systolic myocardial mass index (MMDI/MMSI), stroke volume and index (SV/SVI), cardiac index (CI) and ejection fraction (EF), as well as the biventricular myocardial strain parameters including global radial/circumferential/longitudinal strain (GRS/GCS/GLS), global radial/circumferential/longitudinal diastolic strain rate (GRSDr/GCSDr/GLSDr) were measured and calculated. Demographic data, kinematic index, cardiac function and myocardial strain parameters were compared between the two groups.Results:Compared with the control group, the exercise group showed significant decrease heart rates ( P<0.001). It was found that the left ventricular function parameters (ESVI, MMD, MMDI, MMS, MMSI) and the right ventricular function parameters (EDVI, ESVI) of the exercise group were significantly higher than those of control group (all P<0.05); while the left ventricular strain parameters (GCS, GRSDr, GCSDr, GLSDr) and the right ventricular strain parameters (GRSDr, GLSDr) were of the exercise group were significantly lower than those of control group (all P<0.05). Conclusions:Amateur marathon runners have lower myocardial strain capacity and higher left ventricular myocardial mass. The ventricular diastolic strain rate may sensitively reflect the compensatory changes of ventricular function with the normal ejection fraction.