| 【Objective】Large-area cartilage defect has been difficult to treat in orthopedics for years. Thereare a number of ways to repair cartilage defect at present, such as cartilage graft repair,perichondrium or periosteum graft repair and autologous chondrocytes implantation.However, tissue engineering is one of the hot spot and the most promising method amongthe others, which integrates seed cells, scaffolds and the construction of tissue-engineeredbone. Many scholars have been seeking suitable biomaterials for cartilage tissueengineering and conceived various composite materials as scaffold. However, in mostresearches, cell division, proliferation and migration have not been considered, and theeffects of material degradation on cell activity have also not been investigated. Here, weintroduce a new type of porous composite scaffold, nano-hydroxyapatite/polyaiticglycolicacid (nHA/PLGA), and explore its biocompatibility with rabbit chondrocytes through invitro co-culture experiments. To examine the biocompatibility of a novel nano-hydroxyapatite/poly lactic-co-glycolic acid (nHA/PLGA) composite and evaluate itfeasibility as a scaffold for bone tissue engineering．【Methods】Low temperature rapid prototyping technology was used to prepare the three-dimensional porous nHA/PLGA composite. The sample could be cut to proper size and via CO60sterilization and dry for the co-culture experiment. The fetal rabbit chondrocyteswere seeded with scaffolds for experimental group (Group A) and in well plate alone ascontrol group (Group B), namely, co-culture of cells and the scaffolds. MTT assay wasused to test the cell viability in day1, day3, day5, day7and day9. The absorbances weremeasured at490nm using a microplate reader, and then draw a cell activity contrast figure.A microscope was used to observe the cells of group A and group B in day1, day3andday5. Scanning electron microscopy (SEM) was used to characterize the cell morphologyon the biphasic composite. Cell cycles were tested using a flow cytometer and the profileswere obtained by flow cytometry analysis. Proliferation index (PI) was calculated andstudied by statistical analysis.【Results】The absorbances were measured in day1, day3, day5, day7and day9. Theabsorbance of group A and group B increased in a similar pattern, no significance wasobserved between group A and group B (P﹥0.05) as regard to cell proliferative capability.Chondrocytes in group A and group B were imaged and analyzed by inverted microscope.In both groups, the chondrocytes were observed triangle-shaped, disc-shaped andmegagon-shaped. The cells were connected by cellular processes. The chondrocytesobserved kept proliferating and differentiating during culture. Chondrocytes on thescaffold imaged by SEM showed good extension capability and were fusifomis-shaped.The cells increased in a time-dependent manner and gradually fused. After7days inculture, chondrocytes in both groups were in normal shape and no abnormal diploid cellwas observed. nHA/PLGA scaffold had little influence in cell growth. No significance wasobserved between the two groups (P>0.05).【Conclusion】The present study investigated the feasibility of nHA/PLGA being a biocompatiblescaffold by cell viability test, microscope and SEM observation and flow cytometryanalysis of the cell cycle. MTT assay tested cell activity, which indicated the scaffold itself had no effect on chondrocyte proliferation. Inverted microscope and SEMobservation showed cell morphology at different periods of culture. With the extension ofincubation time, the chondrocytes could normally adhere to the stent surface and rapidlyproliferate. Flow cytometry analysis found that the scaffold had no effect on cell cycle. Noabnormal diploid cell was found, thus the scaffold materials have no tumorigenicity. Ingeneral, nHA/PLGA porous scaffolds used in this experimental study have no adverseeffects on chondrocyte adhesion, growth, proliferation and differentiation. Therefore, thenHA/PLGA porous scaffold is with good cell compatibility and a good kind of cartilagetissue engineering scaffold. |
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