[Effects of enamel matrix proteins on attachment, proliferation and pre-mRNA of type I collagen synthesis of human dermal fibroblast cells in vitro].

OBJECTIVE: To investigate the influence of enamel matrix proteins (EMPs) on the attachment, proliferation and pre-mRNA of type I collagen synthesis of cultured human dermal fibroblast cells.

METHODS: Human dermal fibroblast cells were obtained from human acrobystia and cultured in DMEM medium with 10% FBS. The 3rd to 6th passage cells were used. Ninety-six-well plates and 6-well plates were pre-coated with different concentrations of EMPs (50, 100, 150 and 200 microg/mL). (1) The cell attachment experiment: 0.2 mL cells suspension at the concentration of 1 x 10(6)/mL was added to the pre-coated 96-well plates as the experimental groups (groups A, B, C and D based on different concentrations of EMPs). At 1.5, 3.0, and 4.5 hours after inoculation, the attached cells were measured by MTT method. (2) The cell proliferation experiment: 0.2 mL cells suspension at the concentration of 5 x 10(4)/mL was added to the pre-coated 96-well plates as the experimental groups (groups A1, B1, C1 and D1 based on the different concentrations of EMPs). At 2, 4, 6 and 8 days after inoculation, the cells were measured by MTT method. (3) The synthesis experiment of pre-mRNA: 2 mL cells at the concentration of 1 x 10(6)/mL was added to the pre-coated 6-well plates as the experimental groups (groups A2, B2, C2 and D2 based on different concentrations of EMPs). At 5 days after inoculation, the synthesis of pre-mRNA was measured by RT-PCR method. Human dermal fibroblast cells were added to the un-coated plates as the control groups.

RESULTS: (1) The cell attachment experiment: There were significant differences in attachment cells between the control group, group A and the groups B, C and D (P < 0.05). There were no significant difference between group A and control group (P < 0.05). (2) The cell proliferation experiment: At 2 days, there were no significant differences in absorbance between the control group and the experimental groups (P > 0.05); at 4 days and 6 days, the absorbance of groups B1 (0.598 +/- 0.020 and 0.639 +/- 0.016 ), C1 (0.582 +/- 0.017 and 0.641 +/- 0.020) and D1 (0.574 +/- 0.021 and 0.635 +/- 0.021) was significantly higher than that of the control group (0.548 +/- 0.021 and 0.605 +/- 0.019, P < 0.05); at 8 days, the absorbance of group B1 (0.629 +/- 0.012) and group C1 (0.631 +/- 0.014) was significantly higher than that of the control group (0.606 +/- 0.031, P < 0.05). (3) The synthesis experiment of pre-mRNA: The synthesis of type I collage pre-mRNA of groups B2, C2 and D2 was significantly higher than that of the control group.

CONCLUSION: EMPs stimulate human dermal fibroblast cell attachment, proliferation and synthesis of type I collage pre-mRNA, and its maximal effect can be achieved at the concentration of 100 microg/mL.