Changes in myocardial myosin heavy chain isoform composition with exercise and post-exercise cold-water immersion.

This study investigated the changes in myocardial myosin heavy chain (MHC) isoforms, MHC-α and MHC-ß composition in young healthy rodents following endurance training, with and without post-exercise cold-water immersion (CWI). Male rats were either trained on a treadmill for 10 weeks with (CWI) or without (Ex) regular CWI after each running session, or left sedentary (CON). Left ventricular mRNA of MHC-α, MHC-ß, thyroid receptor α1 (TR-α1) and ß (TR-ß) were analyzed using rt-PCR and semiquantitative PCR analysis. MHC isoform protein composition was determined using SDS-PAGE electrophoresis. MHC-α isoform protein was predominant in all groups. The relative expression of MHC-ß (%MHC-ß) protein was not different between groups (CWI 34.7 ± 6.9%; Ex 32 ± 5.3%; CON 35.5 ± 10%; P = 0.7). MHC-ß mRNA was reduced in Ex (0.7 ± 0.3-fold) compared to CWI (1.3 ± 0.2-fold; P < 0.001) and CON (1.01 ± 0.2-fold; P = 0.03). TRα1 mRNA was lower in CWI (0.4 ± 0.05-fold) than Ex (1.02 ± 0.3-fold) and CON (1.01 ± 0.2-fold) (P < 0.001 for both). CWI exhibited greater %MHC-ß mRNA (56.8 ± 4.1%) than Ex (44.4 ± 7.7%; P = 0.001) and CON (48.5 ± 7.8%; P = 0.03). Neither exercise nor post-exercise CWI demonstrated a distinct effect on myocardial MHC protein isoform composition. However, CWI increased the relative expression of MHC-ß mRNA compared with Ex and CON. Although this implicates a potential negative long-term impact of post-exercise CWI, future studies should include measures of cardiac function to better understand the effect of such isoform mRNA shifts following regular use of CWI.

The impact of solvent selection on the characteristics of niosome nanoparticles prepared by microfluidic mixing.

The aim of this work was to assess the impact of solvent selection on the characteristics of niosomes prepared by microfluidic mixing. To achieve this, niosomes were manufactured using bench-scale microfluidic mixing systems by changing the type of aqueous and/or organic solvents used to prepare the particles. Niosomes were prepared using different non-ionic surfactants and cholesterol compositions with different solvents and evaluated to investigate the influence of organic and aqueous solvents on the particle's physiochemical characteristics. Here we demonstrated that the solvent selection is a key factor to be considered during the preparation of niosomes with microfluidic mixing. The type of organic solvent was shown to significantly affect the size and the size distribution of the prepared particles. In general, niosome size increased with increasing organic solvent polarity, without affecting the niosomes stability. Moreover, changing the aqueous solvent used to hydrate the lipid components significantly (p < 0.05) affected the characteristics of the prepared niosomes in terms of particles size, size distribution, and surface charge. This impact of solvent selection on the final product is dependent on the lipid components where niosomes prepared with different compositions will have different characteristics when changing the type of organic and/or aqueous solvents. The apparent encapsulation efficiency of quinine as a model hydrophobic drug was subsequently shown to be significantly (p < 0.05) affected by the type of the organic solvent used to prepare the niosomes, while the impact of the organic solvent had less impact on the apparent encapsulation of atenolol as a model hydrophilic drug.

Alleviation of diabetic nephropathy by zinc oxide nanoparticles in streptozotocin-induced type 1 diabetes in rats.

This study examines the effect of nanoparticles with zinc oxides (ZnONPs) on diabetic nephropathy, which is the primary cause of mortality for diabetic patients with end-stage renal disease. Diabetes in adult male rats was induced via intraperitoneal injection of streptozotocin. ZnONPs were intraperitoneally administered to diabetic rats daily for 7 weeks. Diabetes was associated with increases in blood glucose level, 24-h urinary albumin excretion rate, glomerular basement membrane thickness, renal oxidative stress markers, and renal mRNA or protein expression of transforming growth factor-ß1, fibronectin, collagen-IV, tumour necrosis factor-α and vascular endothelial growth factor-A. Moreover, the expression of nephrin and podocin, and the mRNA expression of matrix metalloproteinase-9 were decreased in the diabetic group. These changes were not detected in the control group and were significantly prevented by ZnONP treatment. These results provide evidence that ZnONPs ameliorate the renal damage induced in a diabetic rat model of nephropathy through improving renal functionality; inhibiting renal fibrosis, oxidative stress, inflammation and abnormal angiogenesis; and delaying the development of podocyte injury. The present findings may help design the clinical application of ZnONPs for protection against the development of diabetic nephropathy.

Modulation of cardiac vascular endothelial growth factor and PGC-1α with regular postexercise cold-water immersion of rats.

Myocardial mitochondrial biogenesis and vascular angiogenesis biomarker responses to postexercise cold-water immersion (CWI) have not been reported. Therefore, to determine those cardiac adaptations, adult male Sprague-Dawley rats were divided into three groups: postexercise CWI (CWI; n = 13), exercise only (Ex; n = 12), and untreated control (CON; n = 10). CWI and Ex were trained for 10 wk, 5 sessions/wk, 30-60 min/session. CWI rats were immersed after each session in cold water (15 min at ~12°C). CON remained sedentary. Left ventricle tissue was obtained 48 h after the last exercise session and analyzed for peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), vascular endothelial growth factor (VEGF), and heat shock protein 70 kDa (Hsp70) protein content and mRNA expression levels. In addition, superoxide dismutase activity and mRNA and malondialdehyde levels were evaluated. Ex and CWI induced higher PGC-1α protein content compared with CON (1.8 ± 0.6-fold, P < 0.001), which was significantly higher in CWI than Ex rats (P = 0.01). VEGF protein (4.3 ± 3.7-fold) and mRNA (10.1 ± 1.1-fold) were markedly increased only in CWI (P < 0.001) relative to CON. CWI and Ex augmented cardiac Hsp70 protein to a similar level relative to CON (P < 0.05); however, Hsp70 mRNA increased only in Ex (P = 0.002). No further differences were observed between groups. These results suggest that postexercise CWI may further enhance cardiac oxidative capacity by increasing the angiogenic and mitochondrial biogenic factors. In addition, CWI does not seem to worsen exercise-induced cardioprotection and oxidative stress. NEW & NOTEWORTHY A regular postexercise cold-water immersion for 10 wk of endurance training augmented the myocardial mitochondrial biogenesis and vascular angiogenesis coactivators peroxisome proliferator-activated receptor γ coactivator-1α and vascular endothelial growth factor, respectively. In addition, postexercise cold-water immersion did not attenuate the exercise-induced increase in the cardioprotective biomarker heat shock protein 70 kDa or increase exercise-induced oxidative stress.