[The effects of epidermal growth factor on the wound repair of junctional epithelial cells and gingival epithelial cells in vitro].
OBJECTIVE
To study the effects of epidermal growth factor (EGF) on the proliferation and cellular fill of junctional epithelium (JE) and gingival epithelium (GE) by using an in vitro wound model.


METHODS
EGFR mRNA was semiquantitatively determined by reverse transcriptase polymerase chain reaction (RT-PCR) and immunocytochemistry was performed to measure EGFR expression. JE and GE cells were plated into 6 well tissue culture plates containing 22mm x 26mm sterile glass coverslips. After cells were grown to confluence, a 3mm wide wound was created at the center of the coverslips. The cells were incubated in medium containing EGF at a 20ng/mL concentration. Negative controls were incubated in keratinocyte serum-free medium. At 5, 9 and 12 days following wounding, the coverslips were removed and stained with hematoxylin and eosin (HE) and proliferating cell nuclear antigen (PCNA). Quantification of percentage of cellular wound fill and PCNA positive nuclei was accomplished by using computer assisted histomorphometry.The data were analyzed with SAS6.12 software package.


RESULTS
Densitometric scanning indicated that EGFR mRNA expression in GE cells was 1.2-fold higher than that in JE cells. EGFR protein was positive in GE and JE immunocytochemically. At 9 -day post-wounding, GE and JE demonstrated significantly greater proliferative responses to EGF when compared to negative controls (P<0.05). But there were no significant differences in the proliferative responses to EGF between the two cell types (P>0.05). At each time point, EGF stimulated the cellular fill of JE and GE compared with negative controls (P<0.05). However, GE displayed greater cellular fill significantly than JE at day 9 and 12 post-wounding (P<0.05).


CONCLUSIONS
EGFR is present in the JE and GE cells. EGF may regulate the cell fill and proliferation of the two cell types in this in vitro model.
Li
Shu-bo
SB
Ninth People's Hospital, College of Stomatology, School of Medicine, Shanghai Jiao Tong University, Shanghai , China.
Li
De-yi
DY
D002465:Cell Movement; D066255:EGF Family of Proteins / Q000502:physiology*; D004846:Epithelial Attachment; D004847:Epithelial Cells; D005881:Gingiva; D006801:Humans; D066298:In Vitro Techniques; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D014945:Wound Healing
D066255:EGF Family of Proteins; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger