Body Size Effect in Eothenomys miletus of Different Regions from Hengduan Mountain Regions: Roles of Growth Factor Contents

Abstract

Background: Growth factors are active substances secreted by a variety of cells, acting as messengers to regulate cell migration, proliferation or differentiation, which had important regulatory roles in the growth of individual cells, tissues or organs. Growth factors can regulate the proliferation and differentiation ability of cells, which keep the internal environment stable and affect the body size. Methods: In order to investigate the influence of the changes of growth factors contents on body size in Eothenomys miletus from Hengduan mountain regions, E. miletus in Dali (DL), Jianchuan (JC), Lijiang (LJ), Xianggelila (XGLL) and Deqin (DQ) were collected and their 7 morphological indicators and 9 growth factors, including insulin-like growth factor1 (IGF1), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), growth hormone release inhibitory factor (GRIF), platelet-derived growth factor (PDGF), transcription elongation factor1 (TCEA1), a disintegrin and metalloprotease17 (ADAM7), branched-chain amino acid transaminase1 (BCAT1), high mobility group protein1 (HMG1) were measured. Result: The results showed that body size of E. miletus among five regions had significant differentiated, body mass, body length, forelimb length, hind limb length, tail length, IGF, bFGF, EGF, PDGF, TCEA1 contents in DL, JC and LJ were greater than those of in XGLL and DQ and the contents of GRIF, ADAM7, BCAT1 and HMG1 were also different, decreasing with the increasing of regional latitude. Moreover, the increases in the contents of growth factors lead to the increase of body size in E. miletus, which does not support Bergman's law. Regional differences in body size of E. miletus in different regions may be related to the changes in body mass, morphological indicators and the content of growth factors. Moreover, growth factors may affect the body size of E. miletus by affecting the proliferation of bone, epidermis, muscle and differentiation of cells.