Beijing Research Institute of Traumatology and Orthopaedics, Beijing, 100035, China.
Beijing Jishuitan Hospital, Beijing, 100035, China.
J Orthop Surg Res. 2023 Mar 27;18(1):250. doi: 10.1186/s13018-023-03660-5.
Exosomes derived from bone marrow mesenchymal stem cells (BMSC-Exos) are considered as candidates for osteoporosis (OP) therapy. Estrogen is critical in the maintenance of bone homeostasis. However, the role of estrogen and/or its receptor in BMSC-Exos treatment of OP, as well as its methods of regulation during this process remain unclear.
BMSCs were cultured and characterized. Ultracentrifugation was performed to collect BMSC-Exos. Transmission electron microscopy, nanoparticle tracking analysis, and western blotting were used to identify BMSC-Exos. We examined the effects of BMSC-Exos on the proliferation, osteogenic differentiation, mineralization, and cell cycle distribution of MG-63 cells. The protein expression of estrogen receptor α (ERα) and the phosphorylation of ERK were investigated through western blotting. We determined the effects of BMSC-Exos on the prevention of bone loss in female rats. The female Sprague-Dawley rats were divided into three groups: the sham group, ovariectomized (OVX) group, and the OVX + BMSC-Exos group. Bilateral ovariectomy was performed in the OVX and OVX + BMSC-Exos groups, while a similar volume of adipose tissue around the ovary was removed in the sham group. The rats in OVX group and OVX + BMSC-Exos group were given PBS or BMSC-Exos after 2 weeks of surgery. Micro-CT scanning and histological staining were used to evaluate the in vivo effects of BMSC-Exos.
BMSC-Exos significantly enhanced the proliferation, alkaline phosphatase activity, and the Alizarin red S staining in MG-63 cells. The results of cell cycle distribution demonstrated that BMSC-Exos increased the proportion of cells in the G2 + S phase and decreased the proportion of cells in the G1 phase. Moreover, PD98059, an inhibitor of ERK, inhibited both the activation of ERK and the expression of ERα, which were promoted by administration of BMSC-Exos. Micro-CT scan showed that in the OVX + BMSC-Exos group, bone mineral density, bone volume/tissue volume fraction, trabecular number were significantly upregulated. Additionally, the microstructure of the trabecular bone was preserved in the OVX + BMSC-Exos group compared to that in the OVX group.
BMSC-Exos showed an osteogenic-promoting effect both in vitro and in vivo, in which ERK-ERα signaling might play an important role.
骨髓间充质干细胞（BMSC）衍生的外泌体（BMSC-Exos）被认为是骨质疏松症（OP）治疗的候选物。雌激素在维持骨稳态中起着关键作用。然而，雌激素及其受体在 BMSC-Exos 治疗 OP 中的作用，以及在此过程中的调节方式仍不清楚。
培养并鉴定骨髓间充质干细胞（BMSCs）。通过超速离心收集 BMSC-Exos。采用透射电子显微镜、纳米颗粒跟踪分析和 Western blot 鉴定 BMSC-Exos。检测 BMSC-Exos 对 MG-63 细胞增殖、成骨分化、矿化和细胞周期分布的影响。通过 Western blot 检测雌激素受体α（ERα）的蛋白表达和 ERK 的磷酸化。研究 BMSC-Exos 对雌性大鼠骨丢失的预防作用。将雌性 Sprague-Dawley 大鼠分为三组：假手术组、卵巢切除（OVX）组和 OVX+BMSC-Exos 组。OVX 和 OVX+BMSC-Exos 组行双侧卵巢切除术，假手术组切除卵巢周围相似体积的脂肪组织。OVX 组和 OVX+BMSC-Exos 组术后 2 周分别给予 PBS 或 BMSC-Exos。采用 micro-CT 扫描和组织学染色评估 BMSC-Exos 的体内作用。
BMSC-Exos 显著增强了 MG-63 细胞的增殖、碱性磷酸酶活性和茜素红 S 染色。细胞周期分布结果表明，BMSC-Exos 增加了 G2+S 期细胞的比例，降低了 G1 期细胞的比例。此外，ERK 抑制剂 PD98059 抑制了 BMSC-Exos 促进的 ERK 激活和 ERα 的表达。micro-CT 扫描显示，在 OVX+BMSC-Exos 组中，骨密度、骨体积/组织体积分数和小梁数均显著升高。此外，与 OVX 组相比，OVX+BMSC-Exos 组的小梁骨微观结构得到了保留。
BMSC-Exos 具有体内外促进成骨的作用，其中 ERK-ERα 信号可能发挥重要作用。
