OBJECTIVETo verify whether abnormal expression of calcium/calmodulin dependent serine protein kinase (CASK) and inhibitors of differentiation 1 (ID1) exist in Fb of keloid, and to observe the effect of artesunate on two genes.

METHODSFifteen samples of keloid and 12 samples of normal skin tissue (discarded) excised from patients admitted to our hospital were collected. Tissue particle adherent method was used in the primary culture of Fb, and cells from the third to the eighth passage were used for test. Expressions of CASK and ID1 in Fb harvested from both sources were observed with immunofluorescence staining. Fb of keloid were stimulated with artesunate in various concentration for different time, and the median inhibitory concentration (IC50) was determined with the MTT colorimetric assay, which served as the intervention concentration of artesunate. Fb of normal skin were set as normal control group (NC, treated with medium solution). Fb of keloid were divided into scar control group (SC, treated with medium solution) and scar administration group (SA, treated with artesunate in IC50). The cycle and apoptosis of Fb were detected with flow cytometric assay, and the nucleic acid and protein expressions of CASK and ID1 of Fb in each group were determined with RT-PCR and Western blotting. Data were processed with one-way analysis of variance and LSD-t test.

RESULTSExpressions of CASK and ID1 were detected in two kinds of Fb. The concentration of 75 mg/L was selected as the intervention concentration of artesunate. (1) There were statistically significant differences among the three groups in the percentages of cells in G0/G1 phase and G2/M phase (with F values respectively 118.064 and 163.840, P values all below 0.01). The percentage of cells in G0/G1 phase of group SA was (91.4 ± 1.4)%, which was significantly higher than that of group SC and group NC [respectively (80.7 ± 0.3)% and (82.4 ± 0.6)%, with t values respectively 12.740 and 9.872, P values all below 0.05]. The percentage of cells in G2/M phase of group SA was (6.9 ± 0.3)%, which was significantly lower than that of group SC and group NC [respectively (13.7 ± 0.3)% and (12.7 ± 0.8)%, with t values respectively 43.702 and 12.276, P values all below 0.05]. (2) There were statistically significant differences among the three groups in the early and late apoptotic rates (with F values respectively 61.879 and 4710.862, P values all below 0.01). The early and late apoptotic rates of group SA were respectively (7.1 ± 1.0)% and (14.9 ± 0.3)%, which were significantly higher than those of group SC and group NC [with early apoptotic rate respectively (2.6 ± 0.4)% and (2.7 ± 0.3)%, t values respectively 7.974 and 7.767, P values all below 0.05; with late apoptotic rate respectively (2.3 ± 0.3)% and (2.5 ± 0.4)%, t values respectively 72.882 and 69.792, P values all below 0.05]. (3) The mRNA expression of CASK in group SC was 0.658 ± 0.024, and it was lower than that of group NC (1.076 ± 0.008, t = 28.997, P < 0.01) and group SA (0.855 ± 0.008, t = 13.549, P < 0.01). The protein expression of CASK in group SC was 0.067 ± 0.007, and it was lower than that of group NC (0.179 ± 0.015, t = 12.042, P < 0.01) and group SA (0.132 ± 0.010, t = 9.498, P < 0.01). (4) The mRNA expression of ID1 in group SC was 0.416 ± 0.006, which was higher than that of group NC (0.317 ± 0.020, t = 8.299, P < 0.01) and group SA (0.217 ± 0.009, t = 32.417, P < 0.01). The protein expression of ID1 in group SC was 0.789 ± 0.034, and it was higher than that of group NC (0.366 ± 0.029, t = 16.341, P < 0.01) and group SA (0.114 ± 0.006, t = 33.978, P < 0.01).

CONCLUSIONSIt is speculated that CASK and ID1 participate in the proliferation of Fb in keloid. The mechanism of artesunate in inhibiting the proliferation of Fb in keloid may be related to the up-regulation of CASK and down-regulation of ID1.