[The effects of transforming growth factor-beta1 on the differentiation of BALB/c 3T3 fibroblasts into myofibroblasts and the change of Egr-1 expression].
OBJECTIVE
To investigate the effects of transforming growth factor (TGF)-beta(1) on fibroblasts differentiation into myofibroblasts, and the change of Egr-1 expression in the course of differentiation in BALB/c 3T3 fibroblasts.


METHODS
BALB/c 3T3 fibroblasts of the experiment group were treated with 10 ng/ml TGF-beta(1) and those of the control group were treated without TGF-beta(1). The expression of alpha-smooth muscle actin (SMA) was detected by flow cytometer after incubation for 24, 48, and 72 h. The expression of Egr-1 was detected by immunocytochemistry and Western blot method after 10 ng/ml TGF-beta(1) incubation for 15, 30, 60, 90, 120, 180, and 240 min.


RESULTS
The percentage of alpha-SMA positive cells was (6.65 +/- 0.48)% when cells were treated with 10 ng/ml TGF-beta(1) for 24 h, and the control group was (5.53 +/- 0.62)%, which showed no statistical significance. However the percentage was up to (28.38 +/- 3.60)% after treated with TGF-beta(1) for 48 h, and the control group was (9.49 +/- 0.21)%; At 72 h, the percentage was (36.04 +/- 0.73)% and the control group was (15.23 +/- 0.33)%; The difference was statistically significant. Immunocytochemistry showed that Egr-1 protein positive signal was brown in color. The color was light in the control group. The gray-level of the control group was 38 +/- 18 measured by Western blot when cells were treated without TGF-beta(1). After treated with 10 ng/ml TGF-beta(1) for 15 min, the level was up to 55 +/- 26, which had no statistical significance. The level was increased with longer incubation. It was 115 +/- 14 at 60 min and reached its peak level 129 +/- 22 at 90 min, which was significantly higher than the control group. The level was decreased after 90 min and reached neap 39 +/- 7 at 240 min.


CONCLUSIONS
TGF-beta(1) increased the expression of alpha-SMA in BALB/c 3T3 fibroblasts and affected the Egr-1 protein expression during the early course of fibroblasts differentiation into myofibroblasts.
Niu
Zhi-Wei
ZW
Institute of Respiratory Disease, First Affiliated Hospital of China Medical University, Shenyang 110001, China.
Zhao
Hong-Wen
HW
D000199:Actins / Q000378:metabolism; D000818:Animals; D041702:BALB 3T3 Cells; D002454:Cell Differentiation / Q000187:drug effects; D051766:Early Growth Response Protein 1 / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*
D000199:Actins; D051766:Early Growth Response Protein 1; D053773:Transforming Growth Factor beta1; C544013:alpha-smooth muscle actin, mouse