3-Methyladenine regulating autophagy gene Beclin1 can alleviate the occurrence and development of steroid-induced avascular necrosis of the femoral head / 中国组织工程研究

ABSTRACT

BACKGROUND: Steroid-induced avascular necrosis of the femoral head is a worldwide problem, and its pathogenesis still remains unclear. Its pathogenesis is still the focus of research in this field. OBJECTIVE: To discuss the role of autophagy gene Beclin1 in steroid-induced avascular necrosis of the femoral head and the effect of 3-methyladenine on Beclin1. METHODS: Thirty-six 5-month-old Japanese white rabbits (provided by Xi'an Dilepu Biological Resource Development Co., Ltd.) were included and randomly divided into control group (intramuscular injection of normal saline), avascular necrosis of the femoral head group (intramuscular injection of methylprednisolone) and 3-methyladenine group (intramuscular injection of methylprednisolone and 3-methyladenine), with 12 rabbits in each group. The injection was conducted four times, with 1 week in between. The animals from each group were sacrificed at 1, 2, 3 and 4 weeks for sample taken. Vacant bone lacunae were counted under optical microscope. mRNA and protein expression levels of Beclin1 were detected by RT-PCR and western blot assay. RESULTS AND CONCLUSION: (1) Histomorphological observation under optical microscope showed that the rate of vacant lacunae in the avascular necrosis of the femoral head and 3-methyladenine groups was significantly increased (P ＜ 0.05), and was significantly lower in the 3-methyladenine group than that in the avascular necrosis of the femoral head group (P ＜ 0.05). (2) Glucocorticoid could rapidly stimulate the expression of Beclin1 mRNA in the femoral head tissue, and the protein level was significantly increased at the first two weeks, suggesting that autophagy was activated. 3-Methyladenine could inhibit this process. (3) These findings indicate that enhanced autophagy gene Beclin1 expression is important for avascular necrosis of the femoral head. 3-Methyladenine can regulate Beclin1, thereby controlling autophagy, which alleviates the occurrence and development of avascular necrosis of the femoral head.