Potential of the propolis as storage medium to preserve the viability of cultured human periodontal ligament cells: an in vitro study.

AIM

In vitro experiments were carried out to evaluate the potential of propolis, a natural resin known for its wide therapeutic window, as storage medium to preserve the viability of cultured human periodontal ligament (PDL) cells.

MATERIALS AND METHODS

Primary cultures of human PDL cells were subjected to either independent exposure of propolis (2.5%, 5.0%, 10.0%, and 20.0%), Hank's balanced salt solution (HBSS), milk (0.5%), artificial saliva, Dulbecco's modified Eagle's medium (DMEM) or combination of propolis 10% + DMEM, propolis 20% + DMEM for 30 min to 24 h at 37 °C. Cell viability was assessed using standard endpoints i.e., tetrazolium bromide salt (MTT), neutral red uptake, and trypan blue dye exclusion assay.

RESULTS

In general, combinations of propolis 10% + DMEM, propolis 20% + DMEM, and DMEM alone were found to be better than other media used in this study. The difference in the potentials of these media to maintain the cell viability reached to the statistically significant levels by 24 h, when compared with other media used viz., propolis 2.5% (P < 0.01), propolis 5.0% (P < 0.05), propolis 10.0% (P < 0.05), propolis 20.0% (P < 0.001), HBSS (P < 0.001), and milk (P < 0.01). Trypan blue dye exclusion assay could be recorded the most sensitive among all the assays selected to study the cell viability of PDL cells.

CONCLUSIONS

Study indicates that combinations of propolis 10% + DMEM, propolis 20% + DMEM, and DMEM alone are equally good as storage media of choice to keep PDL cells viable during extra-alveolar period up to 24 h. Other more readily available medium such as milk may serve as appropriate alternative storage medium for shorter time periods i.e., up to 12 h.