Background: Bone remodeling is a complex process that includes continuous resorption
by osteoclast cells and bone formation by osteoblast cells. Bone fragility is a common health issue
of the elderly population, particularly in postmenopausal women. It has been established that steroidal
hormones have an important role in bone homeostasis. Therefore hormone replacement therapy
could have beneficial effects on bone health as compared to other treatments.
Objectives: An imbalance between the rate of bone formation and bone resorption leads to the fragility
of bones. During the current study, we aimed to explore the ability of pregnenolone (1) (PRE),
on proliferation and differentiation of MC3T3-E1 cells. We further aimed to investigate the underlying
mechanism of action for the anabolic effect of PRE (1).
Methods: The effects of pregnenolone (1) on proliferation, differentiation, and mineralization of
MC3T3 osteoblast-like cells were determined. Cell viability was analyzed using MTT assay and
flow cytometry. ALP activity and alizarin staining were employed to evaluate the effect of pregnenolone
on osteoblast differentiation. Moreover, western blot for analysis of certain important proteins,
crucial for the regulation of bone homeostasis, such as BMP2 and RANKL, was also performed.
Results and Discussions: Our results showed that pregnenolone (1) at a concentration of 5 μM
caused a significant (p< 0.05) rise in the growth of MC3T3-E1 cells, whereas a comparable effect
was observed in osteoblast differentiating assays. A significant decrease in RANKL expression was
observed at (0.04 – 1 μM). Our results, therefore, indicated the possible role of pregnenolone (1) in
positive regulation of bone homeostasis by suppressing RANKL expression.
Conclusion: Taken together, our results indicate that pregnenolone (1) has the potential to enhance
osteoblast proliferation, as inferred from the increased number of cells. These results demonstrated that
pregnenolone (1) could be a potential anabolic agent for the treatment of fragility related disorders.