Lin28A alleviates ovariectomy-induced osteoporosis through activation of the AMP-activated protein kinase pathway in rats

Abstract

Aim: To investigate the role of Lin28A in ovariectomy-induced osteoporosis and to elucidate the underlying molecular mechanism.

Methods: Bilateral ovariectomy was conducted to generate an ovariectomy (OVX) rat model. Western blotting was performed to assess the relative expression levels of Lin28A, osteocalcin (OCN), runt-related transcription factor 2 (RUNX2), adenosine monophosphate-activated protein kinase (AMPK) and phosphorylated AMPK (p-AMPK) proteins. Enzyme-linked immunosorbent assays were performed to detect the serum levels of calcium, E2, alkaline phosphatase (ALP) and interleukin (IL)-1β. Three-point bending test was used to assess biomechanical parameters of left femoral diaphysis. Hematoxylin and eosin (HE) staining was conducted to detect the trabecular structure of bone tissue. Dihydroethidium assay kit was used to measure the intracellular reactive oxygen species (ROS) level in osteoclasts. Alizarin red staining revealed the calcium deposit in bone marrow stromal cells (BMSC).

Results: The expression levels of Lin28A, OCN, RUNX2, AMPK and p-AMPK proteins were significantly decreased in OVX rats. The serum levels of calcium, E2, ALP and IL-1β were significantly declined in OVX rats. Biomechanical parameters of left femoral diaphysis were significantly decreased in OVX rats. OVX-induced trabecular abnormalities. ROS level was dramatically increased in the bone tissue of OVX rats, and calcium deposit was dramatically decreased in BMSC cells of OVX rats. These effects induced by OVX could be prevented by overexpression of Lin28A.

Conclusion: Lin28A alleviates ovariectomy-induced osteoporosis through activation of AMPK pathway in rats.

Keywords: AMPK pathway; Lin28A; osteoporosis; ovariectomy.