Effects of cyclic stretch on in vitro culture-tensile stimulation models of myoblasts / 中国组织工程研究

ABSTRACT

BACKGROUND:Endoplasmic reticulum stress participates in the occurrence and development of many diseases, such as atherosclerosis, diabetes, and Alzheimer’s disease. GRP78 is a marker of endoplasmic reticulum stress. The expression of GRP78 reflects the degree of endoplasmic reticulum stress. OBJECTIVE:To investigate the effect of cyclic stretch on GRP78 expression of L6 rat myoblasts, and to identify the relationship between cyclic stretch and endoplasmic reticulum stress. METHODS:In vitro culture-tensile stimulation models of myoblasts of L6 rats were established successful y. The expression of GRP78 of myoblasts exposed to cyclic stretch was determined by reverse transcription-PCR and western blot assay. Stretch groups were subjected to 15%surface elongation at a frequency of 10 cycles per minute, over a period of 1, 6, 12 and 24 hours. cells were simultaneously seeded on a plate in the control and experimental groups with no stimulation. RESULTS AND CONCLUSION:The expression of GRP78 mRNA was continuously elevated over time after stretched treatment, and significant differences were detected as compared with the control group (P<0.05). GRP78 protein expression began to increase at 1 hour after stretched treatment, was significantly increased at 6 hours, peaked at 24 hours, and significant differences were visible as compared with the control group (P<0.05). In conclusion, cyclic stretch induced the occurrence of endoplasmic reticulum stress, which was enhanced with prolonged time. However, prolonged stretch caused severe endoplasmic reticulum stress and leaded to apoptosis of myoblasts.