No Effect of Chromosome 10 from A/J Mouse Strain on Muscle Properties of C57bl/6j Mouse. A Mouse Model of Human Metabolism and Ageing

Abstract

Background. Muscle mass plays a key role in recovery from critical illness or severe trauma. Low skeletal muscle mass is associated with increased mortality risk in patients with coronary heart disease (Nichols et al., 2019). Sarcopenia, low muscle mass, is an increasing problem in our ageing society. The prevalence of sarcopenia varies extremely between elderly cohorts ranging from 7 to over 50% (Bijlsma et al., 2013). Due to their phylogenetic relatedness mice have long served as models of human biology including search for genetic determinants of muscle mass (Morse, 2007). Our aim was to investigate if gene variants that reside in chromosome 10 of A/J mouse strain affect muscle properties of C57BL/6J mouse Methods. We studied C57BL/6J (B6, n = 11) mouse strain and C57BL/6J-Chr10^A/J/NaJ (B6.A10, n = 10) strain which also has B6 strain background, but carry chromosome 10 from A/J strain instead of chromosome 10 from B6 strain. Body mass, soleus (SOL) muscle mass and morphometric characteristics as well as tibia length were Results. SOL mass did not differ between B6 and B6.A10 strains (9.3 ± 0.7mg vs. 9.8 ± 0.4mg, respectively, p > 0.05). There were also no differences in the number of muscle fibres (860 ± 148 vs. 913 ± 136 for B6 and B6.A10 strains, respectively, p > 0.05). B6 and B6.A10 strain mice had similar cross-sectional area of type I (1616µm² ± 303 vs. 1752µm² ± 136, B6 and B6.A10 mice, p > 0.05) and type II fibres (1689µm² ± 291 vs.1734µm² ± 179, B6 and B6.A10 mice, p > Conclusion. Chromosome 10 of B6.A10 mice does not harbour any genes that would affect muscle properties of B6 mice.

Keywords: muscle mass, cross-sectional area, muscle fibres.