Steady Augmentation of Anti-Osteoarthritic Actions of Rapamycin by Liposome-Encapsulation in Collaboration with Low-Intensity Pulsed Ultrasound

Abstract

Chung-Hwan Chen,1,2 Shyh Ming Kuo,3 Yin-Chun Tien,4,5 Po-Chih Shen,4 Yi-Wen Kuo,6 Han Hsiang Huang7 1Department of Orthopedics and Orthopedic Research Center, Kaohsiung Municipal Ta-Tung Hospital and Kaohsiung Medical University Hospital, College of Medicine, Kaohsiung Medical University, Kaohsiung City 80708, Taiwan; 2Institute of Medical Science and Technology, National Sun Yat-Sen University, Kaohsiung City 80424, Taiwan; 3Department of Biomedical Engineering, I-Shou University, Kaohsiung City 82445, Taiwan; 4Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung City 80708, Taiwan; 5Department of Orthopedics, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; 6Orthopedic Research Center, Kaohsiung Medical University, Kaohsiung City 80708, Taiwan; 7Department of Veterinary Medicine, National Chiayi University, Chiayi City 60054, TaiwanCorrespondence: Han Hsiang Huang 580 Xinmin Road, Chiayi City 60054, TaiwanTel [phone]Fax [phone]Email [email protected]: Rapamycin has been considered as a potential treatment for osteoarthritis (OA). Drug carriers fabricated from liposomes can prolong the effects of drugs and reduce side effects of drugs. Low-intensity pulsed ultrasound (LIPUS) has been found to possess anti-OA effects.Materials and Methods: The anti-osteoarthritic effects of liposome-encapsulated rapamycin (L-rapa) combined with LIPUS were examined by culture of normal and OA chondrocytes in alginate beads and further validated in OA prone Dunkin-Hartley guinea pigs.Results: L-rapa with LIPUS largely up-regulated aggrecan and type II collagen mRNA in human OA chondrocytes (HOACs). L-rapa with LIPUS caused significant enhancement in proteoglycan and type II collagen production in HOACs. Large decreases in both MMP-13 and IL-6 proteins were found in the HOACs exposed to L-rapa with LIPUS. Intra-articular injection of 40 μL L-rapa at both 5 μM and 50 μM twice a week combined with LIPUS thrice a week for 8 weeks significantly increased GAGs and type II collagen in the cartilage of knee. Results on OARSI score showed that intra-articular injection of 5 μM L-rapa with LIPUS displayed the greatest anti-OA effects. Immunohistochemistry revealed that L-rapa with or without LIPUS predominantly reduced MMP-13 in vivo. The values of complete blood count and serum biochemical examinations remained in the normal ranges after the injections with or without LIPUS. These data indicated that intra-articular injection of L-rapa collaborated with LIPUS is not only effective against OA but a safe OA therapy.Conclusion: Taken together, L-rapa combined with LIPUS possessed the most consistently and effectively anabolic and anti-catabolic effects in HOACs and the spontaneous OA guinea pigs. This study evidently revealed that liposome-encapsulation collaborated with LIPUS is able to reduce the effective dose and administration frequency of rapamycin and further stably reinforce its therapeutic actions against OA.Keywords: liposome-encapsulation, rapamycin, osteoarthritis, low-intensity pulsed ultrasound, OA prone Dunkin-Hartley guinea pigs

Keywords

• liposome-encapsulation
• rapamycin
• osteoarthritis
• low-intensity pulsed ultrasound
• oa prone dunkin-hartley guinea pigs