YAŞAM ALANI SINIRLANDIRILAN SIÇANLARIN İSKELET KASINDA OKSİDATİF HASARIN İNCELENMESİ

Abstract

In addition to its primary function in maintaining body posture and movement, skeletal muscle is critical in regulating metabolic genes and maintaining metabolic homeostasis and glycemic control. Splint or casting immobilization due to bone fractures and prolonged bed rest after trauma and operations have an adverse effect on skeletal muscle structure and function, causing skeletal muscle atrophy. A balance between the production of free radicals and the antioxidant defense system is necessary for cellular functions. Increased free radical production causes the oxidation of lipids, proteins, and nucleic acids, which is defined as oxidative stress. Studies using immobilization models in animals such as casting and hind limb suspension have demonstrated an increase in oxidative stress biomarkers. However, these animal models are different in terms of the degree of inactivity, and they do not mimic long-term bed rest in humans. A new immobilization model has been designed based on cage volume reduction. It has been reported that this model mimics better reduced daily ambulatory motions and inactivity in bed rest conditions compared to casting and unloading models. Therefore, it is aimed to be investigated the effect of seven days of immobilization based on cage volume reduction on oxidative stress markers such as lipid peroxidation and protein oxidation in the soleus muscle. Wistar albino rats were randomly divided into control (C; n=8) and immobilization (I; n=8). Animals in group C were housed in standard rat cages whereas in group I were housed in a cage volume reduction modal for seven days. Following the experimental procedure, soleus muscles were isolated. To investigate the effect of immobilization on oxidative damage, protein carbonyl, and advanced oxidation protein products (AOPP) were analyzed spectrophotometrically as protein oxidation markers. 4-hydroxynonenal (4-HNE) levels were analyzed by Western Blot as a lipid peroxidation marker. Seven days of immobilization in cage volume reduction caused a 17,2% decrease in the ratio of soleus/body weight. AOPP (p=0,000) and 4-HNE levels (p=0,013) were increased in group I compared to group C, but protein carbonyl levels did not change in soleus muscle (p=0,846). These findings show that oxidative damage in rat skeletal muscle by using a cage volume reduction model mimics bed rest and inactivity, where neural stimuli are greatly reduced in humans.