Valipour Fereshteh, Valipour Farzaneh, Rahbarghazi Reza, Navali Amir Mohammad, Rashidi Mohammad Reza, Davaran Soodabeh
Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
Department of Medicinal Chemistry, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.
J Biol Eng. 2021 Feb 15;15(1):6. doi: 10.1186/s13036-021-00257-6.
The goal of the present study was to create a new biodegradable hybrid PCL-P (HEMA-NIPAAm) thermosensitive hydrogel scaffold by grafting PNIPAAm-based copolymers with biodegradable polyesters to promote the chondrogenic differentiation of human progenitor cells (adipose-derived stem cells-hASCs) in the presence of the platelet-derived growth factor (PDGF-BB). Different mixture ratios including 50 mmol ε-caprolactone and 10 mmol HEMA (S-1), 30 mmol ε-caprolactone and 10 mmol HEMA (S-2), 10 mmol ε-caprolactone and 30 mmol HEMA (S-3) were copolymerized followed by the addition of NIPAAm.
A mild to moderate swelling and wettability rates were found in S-2 group copmpared to the S-1 ans S-3 samples. After 7 weeks, S-2 degradation rate reached ~ 43.78%. According to the LCST values, S-2, reaching 37 °C, was selected for different in vitro assays. SEM imaging showed nanoparticulate structure of the scaffold with particle size dimensions of about 62-85 nm. Compressive strength, Young's modulus, and compressive strain (%) of S-2 were 44.8 MPa, 0.7 MPa, and 75.5%. An evaluation of total proteins showed that the scaffold had the potential to gradually release PDGF-BB. When hASCs were cultured on PCL-P (HEMA-NIPAAm) in the presence of PDGF-BB, the cells effectively attached and flattened on the scaffold surface for a period of at least 14 days, the longest time point evaluated, with increased cell viability rates as measured by performing an MTT assay (p < 0.05). Finally, a real-time RT-PCR analysis demonstrated that the combination of PCL-P (HEMA-NIPAAm) and PDGF-BB promoted the chondrogenesis of hASCs over a period of 14 days by up-regulating the expression of aggrecan, type-II collagen, SOX9, and integrin β1 compared with the non-treated control group (p < 0.05).
These results demonstrate that the PCL-P(HEMA-NIPAAm) hydrogel scaffold carrying PDGF-BB as a matrix for hASC cell seeding is a valuable system that may be used in the future as a three-dimensional construct for implantation in cartilage injuries.
本研究的目的是通过将基于聚N-异丙基丙烯酰胺（PNIPAAm）的共聚物与可生物降解的聚酯接枝，制备一种新型的可生物降解的混合聚己内酯-聚（甲基丙烯酸-2-羟乙酯-N-异丙基丙烯酰胺）（PCL-P(HEMA-NIPAAm)）热敏水凝胶支架，以促进人祖细胞（脂肪来源干细胞-hASCs）在血小板衍生生长因子（PDGF-BB）存在下的软骨形成分化。将不同的混合比例，包括50 mmol ε-己内酯和10 mmol甲基丙烯酸-2-羟乙酯（S-1）、30 mmol ε-己内酯和10 mmol甲基丙烯酸-2-羟乙酯（S-2）、10 mmol ε-己内酯和30 mmol甲基丙烯酸-2-羟乙酯（S-3）进行共聚，然后加入N-异丙基丙烯酰胺。
与S-1和S-3样品相比，S-2组的溶胀和润湿性速率为轻度至中度。7周后，S-2的降解率达到约43.78%。根据最低临界溶液温度（LCST）值，选择达到37°C的S-2用于不同的体外试验。扫描电子显微镜（SEM）成像显示支架具有纳米颗粒结构，粒径约为62-85 nm。S-2的抗压强度、杨氏模量和压缩应变（%）分别为44.8 MPa、0.7 MPa和75.5%。总蛋白评估表明，该支架具有逐渐释放PDGF-BB的潜力。当在PDGF-BB存在下将hASCs接种在PCL-P(HEMA-NIPAAm)上培养时，细胞在支架表面有效附着并铺展至少14天，这是评估的最长时间点，通过MTT试验测量细胞活力率增加（p<0.05）。最后，实时逆转录聚合酶链反应（RT-PCR）分析表明，与未处理的对照组相比，PCL-P(HEMA-NIPAAm)和PDGF-BB的组合在14天内通过上调聚集蛋白聚糖、II型胶原蛋白、SOX9和整合素β1的表达促进了hASCs的软骨形成（p<0.05）。
这些结果表明，携带PDGF-BB作为hASC细胞接种基质的PCL-P(HEMA-NIPAAm)水凝胶支架是一种有价值的系统，未来可作为三维构建体用于软骨损伤的植入。
