ABSTRACT. Hypoxia influences many physiological processes, such as respiration, cardiovascular, neurophysiology, and digestion. Skeletal muscle is an important motor organ, which relies on oxygen of oxidation; however, the study of hypoxia in skeletal muscle is lacking. In order to understand the effect of hypoxia on skeletal muscle, we determined the expression level of four hypoxia-related genes (ADAM17, ARG2, MMP, and HIF1A) in two distinct skeletal muscle tissues from Tibetan pigs that live at different altitudes (500 and 3650 m). Consistent with the well-characterized role of four hypoxia-related genes in the adaptation to high altitude, we found that, compared with the plain pigs, the plateau pigs had higher mRNA abundances of the four genes and lower myofiber ratio in skeletal muscle. The negative correlation between the myofiber ratio and mRNA abundance of the four hypoxia-related genes highlights their critical roles in skeletal 11588 J. Zhang et al. ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (3): 11587-11593 (2015) muscle. These findings may be important for understanding skeletal muscle adaptation to high altitude and hypoxia-related muscle diseases in humans.

1. The low-density lipoprotein receptor-related protein 8 (LRP8), a member of the low-density lipoprotein receptor (LDLR) gene family, participates in the supplying of lipid during follicular development. The objective of the study was to identify and characterise the LRP8 gene in goose. 2. A 2867 bp fragment that covered the complete coding region (CDS) of goose (Anser cygnoides) LRP8 gene was cloned. It encoded a protein of 917 amino acid residues containing a 24-amino acid signal peptide and 5 functional domains. The goose LRP8 showed high nucleic acid and amino acid identities with those in other species. 3. Similarly to duck LRP8 gene, two splice variants of LRP8, LRP8-1 (containing 8 ligand-binding repeats) and LRP8-2 (containing 7 ligand-binding repeats), were identified in goose. 4. Semi-quantitative RT-PCR analysis indicates that the LRP8-1 transcript is expressed in heart, liver, spleen, lung, kidney, breast muscle, duodenum, hypothalamus, pituitary and ovary, negligible or absent in sebum and oviduct, and the LRP8-2 transcript is widely expressed in all examined tissues. 5. A total of 7 SNPs were identified in the coding region of the goose LRP8 gene.