Predominant synthesis of giant myofibrillar proteins in striated muscles of the long-tailed ground squirrel Urocitellus undulatus during interbout arousal.

Molecular mechanisms underlying muscle-mass retention during hibernation have been extensively discussed in recent years. This work tested the assumption that protein synthesis hyperactivation during interbout arousal of the long-tailed ground squirrel Urocitellus undulatus should be accompanied by increased calpain-1 activity in striated muscles. Calpain-1 is known to be autolysed and activated in parallel. Western blotting detected increased amounts of autolysed calpain-1 fragments in the heart (1.54-fold, p < 0.05) and m. longissimus dorsi (1.8-fold, p < 0.01) of ground squirrels during interbout arousal. The total protein synthesis rate determined by SUnSET declined 3.67-fold in the heart (p < 0.01) and 2.96-fold in m. longissimus dorsi (p < 0.01) during interbout arousal. The synthesis rates of calpain-1 substrates nebulin and titin in muscles did not differ during interbout arousal from those in active summer animals. A recovery of the volume of m. longissimus dorsi muscle fibres, a trend towards a heart-muscle mass increase and a restoration of the normal titin content (reduced in the muscles during hibernation) were observed. The results indicate that hyperactivation of calpain-1 in striated muscles of long-tailed ground squirrels during interbout arousal is accompanied by predominant synthesis of giant sarcomeric cytoskeleton proteins. These changes may contribute to muscle mass retention during hibernation.

Serum cytokine profile during subcutaneous implantation of the decellularized esophagus matrix in rats.

AIM: to study non-specific immune response characteristics (serum cytokine profile) in rats after subcutaneous implantation of the decellularized esophagus matrix. METHODS: Data were obtained in Wistar rats. The rats underwent subcutaneous implantation of decellularized esophagus (DE) and native allogeneic esophagus (NE). Explantation of sampling were carried out on the 7th, 14th and 21st day of the experiment. Explanted NEs and DEs were processed for histologic examination. The content of IL1α, IL2, IL4, IL17А, TNFα, IFNγ and GM-CSF in serum samples were tested by ELISA. RESULTS: In rat serum with DEs on the 7th day of the experiment it was significant increase in IL1α level in comparison with control group, IL2, TNFα, IL4 levels did not differ from the control group levels that indicates the stabilization of inflammation. The content of IL17A, IFNγ and GM-CSF significantly decreased compared to control. On the 14th day, IL17A concentration analysis showed a sharp decrease in comparison with the the 7th experimental day. We found decrease in IL1α level vs control group and decrease in IFNγ level vs 7th day. On the 21st experimental day was shown a significant decrease in the IL17A, IFNγ and IL1α content in DE rats. CONCLUSIONS: It was found dynamic change in studied rat cytokine concentrations that correspond to favourable clinical picture in DE group in comparison with an active inflammatory reaction in NE group. IL1α, IL4, IL17A and IFNγ concentrations reflect positive dynamics of the wound healing process and the absence of local inflammation and rejection of decellularized matrices.