Changes in the Diaphragm Lipid Content after Administration of Streptozotocin and High-Fat Diet Regime

Abstract

The diaphragm is a dome-shaped skeletal muscle indispensable for breathing. Its activity contributes up to 70% of the total ventilatory function at rest. In comparison to other skeletal muscles, it is distinguished by an oxidative phenotype and uninterrupted cyclic contraction pattern. Surprisingly, the research regarding diaphragm diabetic phenotype particularly in the light of lipid-induced insulin resistance is virtually nonexistent. Male Wistar rats were randomly allocated into 3 groups: control, streptozotocin-induced (STZ) type-1 diabetes, and rodents fed with high-fat diet (HFD). Additionally, half of the animals from each group were administered with myriocin, a robust, selective inhibitor of ceramide synthesis and, therefore, a potent agent ameliorating insulin resistance. Diaphragm lipid contents were evaluated using chromatography. Fatty acid transporter expression was determined by Western blot. The STZ and HFD rats had increased concentration of lipids, namely, ceramides (CER) and diacylglycerols (DAG). Interestingly, this coincided with an increased concentration of long-chain (C ≥ 16) saturated fatty acid species present in both the aforementioned lipid fractions. The CER/DAG accumulation was accompanied by an elevated fatty acid transporter expression (FATP-1 in HFD and FATP-4 in STZ). Surprisingly, we observed a significantly decreased triacylglycerol content in the diaphragms of STZ-treated rats.

Small-hairpin RNA and pharmacological targeting of neutral sphingomyelinase prevent diaphragm weakness in rats with heart failure and reduced ejection fraction

“…1. The predominant ceramide species in the diaphragm was C18, in agreement with previous reports (19,40). Two-way ANOVA showed no significant interaction effect for any ceramide subspecies or total ceramide.…”

Treadmill Running Changes Endothelial Lipase Expression: Insights from Gene and Protein Analysis in Various Striated Muscle Tissues and Serum

“…The results seem to be rather in line with the common belief that EL level is higher in tissues characterized by high O 2 consumption and rich vascularization, after all, EL is produced by endothelium lining blood vessels. The heart and diaphragm seem to fit nicely in this pattern since they are both tissues with high oxidative capacity, and uninterrupted rhythmical contractile patterns [ 38 , 39 ]. The right ventricle, however, resembles rather skeletal muscle in this respect.…”

Ceramides as Emerging Players in Cardiovascular Disease: Focus on Their Pathogenetic Effects and Regulation by Diet

“…In keeping with this, it has been shown that HFDs were able to increase circulating, as well as tissue ceramide levels, in animal models. Indeed, an increase in ceramides C16:0 and C22:0 [ 62 , 63 ] was reported in the liver, whereas an induction of ceramide C18:0 was detected in the skeletal muscle of high-fat-fed rodents [ [64] , [65] , [66] ].…”