ABSTRACT
BACKGROUND: The balance between bone formation and bone resorption plays an important role in maintaining bone mass, and the stability and balance of the internal environment are affected by many factors.Ghrelin, a major hormone that regulates the secretion of growth hormone, plays a critical part in bone remodeling and body energy metabolism.OBJECTIVE: To investigate the effect of ghrelin on the release of growth hormone and its effect on osteoblast proliferation and bone growth.METHODS: PubMed and WanFang databases were retrieved for the Chinese and English literature addressing the mechanism of ghrelin and the effects of ghrelin on osteoblast proliferation, bone metabolism and bone remodeling published from 1999 to 2016. The repetitive articles were excluded.RESULTS AND CONCLUSION: Ghrelin is involved in the regulation of pituitary growth hormone release, energy metabolism, inflammatory response and osteogenesis. Ghrelin can promote the differentiation and proliferation of osteoblasts and can be secreted by chondrocytes, participating in bone metabolism and growth. Ghrelin can be used as an important target of bone growth, but its mechanism is complex and needs to be further studied.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the effects of TNF alpha on the expression of sterol regulatory element binding proteins cleavage activating protein (SCAP) and triglyceride contents in cells of a model of cultured steatotic hepatocytes.</p><p><b>METHODS</b>A steatotic hepatocytes model was established by treating L-02 cell strain with oleic acid. The cells were treated with TNF alpha and/or TNF alpha antibody. The cells were divided into six groups: a control group (C), a model group (F), a control group with TNF alpha (C1), a control group with TNFalpha antibody (C2), a model group with TNFalpha(F1) and a model group with TNFalpha antibody (F2). The expression of SREBP-1c mRNA was measured with RT-PCR; the protein expression of SCAP was measured by Western blot; lipid droplets in the hepatocytes were observed with oil red O staining; the contents of triglyceride in hepatocytes were measured with an analytical kit.</p><p><b>RESULTS</b>The mRNA expression of SCAP in the groups treated with TNF alpha were upregulated compared with those of the control group (C1 vs C increased 67%, F1 vs F increased 55%, F = 212.98), the protein expression of SCAP in the groups treated with TNF alpha was upregulated compared with those of the control group (C1 vs C increased 45%, F1 vs F increased 95%, F = 104.3), and triglyceride contents in hepatocytes of these groups were increased compared with those of the control group [C (2.02+/-0.67) mg/10(7) cells, F(7.79+/-1.35) mg/10(7) cells, F1(13.36+/-1.99) mg/10(7) cells, F = 82.94].</p><p><b>CONCLUSION</b>TNF alpha upregulates the expression of SCAP and promotes the synthesis of triglyceride; it probably participates in the process of developing steatosis of hepatocytes.</p>