OBJECTIVETo investigate of proliferating cell nuclear antigen (PCNA), C-fos and Bax proteins in human embryonic tongue tissue of different developmental stages.

METHODSImmunohistochemistry was used to detect the expressions of PCNA, C-fos and Bax proteins in embryonic tongue tissues of fetuses with 2, 3 and 4 month gestational age (n=16). One-way ANOVA and LSD-t test were employed to compare the number of positive expression cells in tongue tissues of fetuses with different gestational age.

RESULTSIn the fetuses at 2, 3 and 4 months of gestation, the numbers of PCNA-positive cells in tongue epithelial tissues were 20.20 ± 7.13, 39.10 ± 13.44 and 26.00 ± 9.02, respectively; those in tongue muscle and fiber tissues were 17.20 ± 8.99, 22.30 ± 6.57 and 32.40 ± 14.72, respectively. In fetuses at 2 month of gestation, no C-fos-positive cells were found in tongue tissues; while at 3 and 4 months of gestation, the numbers of C-fos-positive cells in the tongue epithelial layers were 25.10 ± 7.91, 17.40 ± 2.80; those in tongue muscle and fiber tissues were 24.50 ± 4.67 and 28.00 ± 7.75, respectively. Only weak positive expression of Bax protein was observed in the third month of gestation in embryonic tongue tissues. A significant difference was noted in PCNA expression in tongue epithelial layers, the muscle and fiber tissues (P<0.01 and P<0.05) among 3 embryonic periods. A significant difference was found in C-fos expression in tongue epithelial layers (P<0.01), but not in tongue muscle and fiber tissues (P>0.05) among 3 periods.

CONCLUSIONDynamic changes were seen in PCNA and C-fos expressions in embryonic tongue tissues in different gestational ages of fetus, indicating these two proteins may participate in regulation of the development and differentiation of tongue tissues in human embryos and fetuses.