In vitro stimulation of nih 3t3 fibroblast proliferation by interleukin-6 and tumor necrosis factor-alpha generated from peritoneal macrophages activated by silicone gel.

Lee, Paik Kwon; Chun, Ji Hoon; Lee, Jong Won; Han, Ki Taik; Han, Sang Bae; Kim, Hwan Mook

Original Article

Journal of the Korean Society of Plastic and Reconstructive Surgeons 1998;25(5):719-730.
Published online July 1, 1998.

In vitro stimulation of nih 3t3 fibroblast proliferation by interleukin-6 and tumor necrosis factor-alpha generated from peritoneal macrophages activated by silicone gel.

Paik Kwon Lee, Ji Hoon Chun, Jong Won Lee, Ki Taik Han, Sang Bae Han, Hwan Mook Kim

Abstract

Silicone gel breast implants may induce local(fibrous capsular contracture) or systemic(rheumatoid arthritis, systemic sclerosis, etc) complications. The exact mechanism of fibrous capsular contracture has not been fully understood. In the present study, we tried to find out the effect of silicone gel on the fibroblast proliferation which has been known as a major contributing factor in fibrous capsular contracture formation. In vitro, activated macrophages are known to secrete monokines which affect fibroblast proliferation and collagen synthesis. And tumour necrosis factor-alpha(TNF-alpha) and interleukin-6(IL-6), which were released by macrophages, were reported as potent stimulator of fibroblast proliferation. The goal of this study is to investigate the role of macrophages and tumour necrosis factor-alphaor interleukin-6 in the interaction of fibroblasts and silicone gel. We designed four groups, two experimental and two control, using Institute for Cancer Research(ICR) mouse peritioneal macrophage and silicone gel. For the preparation of the conditioned medium of macrophages, peritoneal macrophages were prepared and cultured for 24 hours on the silicone gel-coated and naked (not coated) surface [silicone gel-macrophage conditioned medium(SCM; experimental group) and normal polystyrene-macrophage conditioned medium(NCM; control group) respectively]. To correct the effect of 10% fetal bovine serum which was included in Rapid Prototyping and Manufacturing Institute (RPMI) 1640 medium and draw the effect only by macrophages, the RPMI 1640 medium with 10% fetal bovine serum was cultured by the same method on the silicone gel-coated and naked surface (silicone gel-macrophage free conditioned medium; SFM and normal polystyrene-macrophage free conditioned medium; NFM respectively). Each conditioned medium was added onto NIH 3T3 fibroblasts culture at a final 25% concentration of total culture medium and followed by the cultivation for 24 hours. For antibody neutralizing experiments, each conditioned medium was preincubated with polyclonal rabbit anti-mouse TNF-alpha antibody or polyclonal rat anti-mouse IL-6 antibody for 1 hour and then, conditioned medium with antibody was added to the culture medium of NIH 3T3 fibroblasts by the same method. After 24 hours cultivation, total number of viable fibroblast(cell growth), DNA synthesis and collagen synthesis of fibroblasts with each medium were measured by sulforhodamine B(SRB) assay, 3H-thymidine and 3H-proline incorporation respectively. The results were as follows: 1. In the experiment about the effect of the conditioned medium on the fibroblast activity, the experimental group(SCM), compared with the control group(NCM), showed a significant increase of the cell growth (p<0.01), a significant decrease of DNA synthesis(p<0.001), but no significant difference in the collagen synthesis. 2. In the experiment about the effect of polyclonal rabbit anti-mouse TNF-alpha antibody on the fibroblast activity, after the addition of antibody the experimental group, compared with the control group, showed a significant decrease of the cell growth(p<0.001), a significant increase of DNA synthesis(p<0.01), but no significant difference in the collagen syn thesis. 3. In the experiment about the effect of polyclonal rat anti-mouse IL-6 antibody on the fibroblast activity, after the addition of antibody the experimental group, compared with the control group, showed a significant decrease of the cell growth(p<0.001), a significant increase of DNA synthesis(p<0.0001), but no significant difference in the collagen synthesis. In conclusion, culture supernatants (conditioned medium) of peritoneal macrophages, activated by silicone gel, stimulate the NIH 3T3 fibroblast proliferation. TNF-alpha and IL-6, products of macrophage, are involved in the stimulation of NIH 3T3 fibroblast proliferation in an in vitro condition.