Experimental study on co-culture of DiI labeled rat bone marrow mesenchymal stem cells and polycaprolactone film in vitro to make a cell patch.

Background: In stem cell therapy, due to the lack of an effective carrier, a large number of transplanted stem cells are lost and die. Therefore, finding a suitable carrier has become a further direction of stem cell therapy.

Objective: In research on the co-culture of polycaprolactone (PCL) with 1,1'-Dioctadecyl-3,3,3',3'- tetramethylindocarbocyanine perchlorate (DiI) labeled bone marrow mesenchymal stem cells (BMSCs), we observe the effect of materials on the growth and proliferation of DiI labeled stem cells, and the effect of DiI labeling on patch preparation, so as to find a kind of biomaterial suitable for the growth and proliferation of BMSCs, and find a suitable cell carrier for stem cell therapy of myocardial infarction and in vivo tracing.

Methods: Clean grade Sprague Dawley rats were selected as experimental objects, BMSCs were isolated and cultured, and the surface markers were identified by flow cytometry. After the BMSCs were cultured for 3 passages, the BMSCs were stained with DiI dye, and the BMSCs DiI and PCL biomaterial film were co-cultured. After 24 hours, the cell growth was observed under fluorescence microscope, and fixed for scanning under electron microscope. The cell proliferation was detected by CCK-8 at 1, 4, 7, 10 days of culture. The measurement data conforming to normal distribution are expressed in the form of mean ± standard deviation (X¯± s). One way ANOVA was used for comparison among groups, LSD analysis was used for pairwise comparison. The difference was statistically significant (P < 0.05).

Results: BMSCs were strongly positive for CD90, CD44H, but negative for CD11b/c, CD45. Under fluorescence microscope, BMSCs DiI showed red light, fusiform or polygonal. Under the scanning electron microscope, the cell patch formed by co-culture of PCL film and DiI-BMSCs had a large number of cells on the surface and normal cell state. CCK-8 assay showed that the OD value on the first day was 0.330 ± 0.025; The OD value was 0.620 ± 0.012 on the 4th day, 1.033 ± 0.144 on the 7th day and 1.223 ± 0.133 on the 10th day. There was significant difference among the time points (P < 0.05).

Conclusions: The cell patch made of PCL film and DiI labeled BMSCs can survive and proliferate on the surface, so it can be used as a scaffold material for stem cell therapy in vivo.