以透明質酸修飾的脂質PLGA複合奈米粒子應用於促進骨折癒合

Abstract

骨折癒合包含三個生物階段：炎症、修復和重塑期。許多研究顯示炎症的程度會影響後續骨癒合的過程，導致延遲癒合或骨不癒合的情形發生。近年研究顯示，發現高分子量的透明質酸(Hyaluronic acid，HA)能透過下調 ( down regulate ) 來自成骨細胞和基質細胞的核因子κ-B配體（RANKL）的受體激活來抑制蝕骨細胞分化。此外，也發現HMW-HA可將巨噬細胞由M1型轉變為M2型，緩解炎症反應和促進成骨細胞分化。玻尿酸為細胞外基質中主要成分，並存在於結締組織，已被用作組織工程中的生物材料或用於治療骨關節炎。脂質-PLGA混合型納米顆粒，為脂質層包裹著以聚合物為核心的載體，提供了更好的載藥效率和生物相容性，是新興的藥物遞送平台。在我們的研究，我們將高分子量的透明質酸修飾在脂質-PLG混合型納米顆粒上，並負載抑制發炎藥物來用於幫助骨折的癒合狀況。首先，我們會先合成修飾有HA的LPNs，並進行HA-LPN的表徵鑑定，包括粒徑、ζ電位、官能基、生物毒性和體外釋放曲線。接著，進行RT-PCR和染色以確認負載抗發炎藥物的HA-LPN處理對於炎症緩解和蝕骨細胞分化抑制的作用。根據奈米粒徑及電位分析儀及掃描式電子顯微鏡結果，發現修飾HA的奈米載體相較未修飾載體具有更大粒徑，表面電性更負，證實HA成功修飾在載體上。從細胞實驗結果證實，高分子量的HA確實具有促進成骨細胞增殖分化的能力以及將巨噬細胞由M1型轉變為M2型的功能，並在抗發炎實驗也證實其具有緩解炎症能力。期望負載抗發炎藥物的HA-LPN能對於增強骨折癒合提供可行的治療策略。

Fracture healing occurs in three biological phases: (1) inflammation, (2) repair, and (3) remodeling. The degree of inflammation plays an important role in bone healing process. It was previously reported that high-molecular weight hyaluronic acid (HMW-HA) was able to suppress osteoclasts (OC) differentiation via down-regulating the receptor activator of nuclear factor kappa-Β ligand (RANKL) from osteoblasts (OB) and stromal cells. Additionally, HMW-HA could switch the macrophages from M1 type to M2 type, relieving the inflammation and enhancing OB differentiation. hyaluronic acid (HA) is abundant in extracellular matrix, and presents in connective tissues, that has been used as a biomaterial in tissue engineering or for treating osteoarthritis clinically. The lipid–PLGA hybrid nanoparticles (LPNs), a lipid layer enveloping the polymer core, provided better drug loading efficiency and biocompatibility and was confirmed as a promising delivery platform. We herein modified LPNs with HMW-HA (HA-LPNs), encapsulating immunomodulation drugs for promoting healing of bone fracture. The characterization of HA-LPNs, including particle size, ζ-potential, biological toxicity, and in vitro releasing profile was carried out. Furthermore, RT-PCR and Western Blotting were performed to confirm the effect of HA-LPN treatment on relief of inflammation and inhibition of OC differentiation. Based on the results acquired by Zetasizer Nano ZS and Scanning Electron Microscope (SEM), we found that HA-LPNs had a larger particle size than LPNs, and the lower negative zeta potential, confirming that HA was successfully modified on the surface of LPNs. We also confirmed that high molecular weight HA could promote proliferation and differentiation of osteoblasts in vitro. Moreover, the ability to relieve inflammation by switching macrophages M1 to M2 was observed. Our HA-LPN treatment offers a feasible therapeutic strategy to enhance bone fracture healing.