Phosphatidylserine nanoliposomes inhibit glucocorticoid-induced osteoporosis: A potential combination therapy with alendronate

The present study aimed to investigate the effects of phosphatidylserine liposomes (PSLs) and phosphatidylserine liposomes containing alendronate (AL-PSLs) on the improvement of methylprednisolone (MP) induced osteoporosis in a rat model. AL-PSLs formulation was prepared, characterized, and evaluated in different pH media to simulate gastrointestinal condition. Osteoporosis was induced by 3 weeks oral administration of MP (10 mg/kg) and then treatment by PSLs, AL-PSLs, and alendronate (AL). Bone metabolic and biomechanical markers were measured in treated rat groups. Also, Tartrate-resistant acid phosphatase (TRAP) staining and histomorphometry were evaluated on bone tissues of treated rats. AL-PSLs were obtained in a size range of 155 nm and negatively surface charge with an entrapment efficiency of 42%. The AL leakage from AL-PSLs did not exhibit a significant difference in acidic or basic media in comparison with the neutral condition. The concentrations of calcium, osteocalcin, bone alkaline phosphatase, and osteoprotegerin (OPG) of serum were significantly increased in PSLs and AL-PSLs treated groups compared to the MP group. Also, PSLs and AL-PSLs significantly improved the thickness and volume of the cortical and trabecular bone mass in treated groups. In addition, TRAP staining indicated a significant decrease of osteoclast number in osteoporotic rats treated with AL-PSLs and PSLs. In this study, AL-PSLs and even PSLs alone made a potential bone mechanical strength in glucocorticoid-induced bone loss more than AL in rats. In conclusion, our findings suggest that PSLs consumption with or without an antiosteoporotic drug might be an applicable choice in control of osteoporosis.