Related Experiment Video
Updated: Sep 25, 2026
Bronchoalveolar Lavage of Murine Lungs to Analyze Inflammatory Cell Infiltration
Published on: May 4, 2017
[Studies on effects of cytokine released from alveolar macrophage induced by mineral dust on lung fibroblast]
Objective:
To understand the role of cytokine released from alveolar macrophage (AM) in lung fibrosis caused by mineral dust.
Methods:
Rabbit's AM obtained by lavage was cultured with mineral dust in vitro. Activities of tumor necrosis factor (TNF) and interleukin 6 (IL-6) in its supernatant were determined with isotope labelling method and MTT colorimetry, respectively. Human fetal lung fibroblast WI-138 was cultured with this supernatant. Proliferation of fibroblast and synthesis of collagen were examined by 3H-thymidine (3H-TdR) and 14C-proline (14C-Pro) incorporation and its total hydroxyproline (HOP) level was analyzed by chloramine-T method.
Results:
Proliferation of lung fibroblast and synthesis of collagen could be enhanced by the supernatant containing AM induced by quartz, asbestos and uranium mineral dust, with 3H-TdR incorporated counts per minute (cpm) of 6,584, 3,848 and 6,893 in the group of 100 micrograms 3H-TdR and 14C-Pro incorporated 27,952, 13,416 and 18,538 in the group of 200 micrograms respectively, which were significantly higher than those in the control group. Total HOP levels in the culture media for lung fibroblast enhanced by AM supernatant were 22.41, 24.00 and 21.39 micrograms/ml, respectively, and was significantly higher than that in the control group (12.91 micrograms/ml). Release of TNF and IL-6 could be stimulated by mineral dust, such as quartz, asbestos and uranium mineral dust, and their activities were significantly higher than those in the control group, with those of 1,396, 1,198 and 852 U/ml in TNF group and 1,336, 1511 and 1,335 U/ml in IL-6 group, respectively. Proliferation of lung fibroblast and synthesis of collagen could be inhibited by antibody against TNF and interferon-r (gamma), and the effect of the latter was weaker than that of the former on inhibition of fibroblast proliferation and the effect on collagen synthesis was just in the opposite direction.
Conclusion:
Lung fibrosis caused by mineral dust correlated with abnormal expression of TNF and IL-6. Antibody against TNF and gamma interferon could antagonize the effect of NTF and IL-6.
Insights
Mineral dust exposure stimulates alveolar macrophages to release tumor necrosis factor (TNF) and interleukin-6 (IL-6), driving lung fibroblast proliferation and collagen synthesis. Antibodies against TNF and gamma interferon can counteract these fibrotic effects.
Area of Science:
- Immunology
- Cell Biology
- Toxicology
Context:
- Alveolar macrophages (AMs) play a crucial role in lung immune responses.
- Mineral dusts are known environmental and occupational lung toxicants.
- The specific mechanisms by which AMs contribute to mineral dust-induced lung fibrosis are not fully understood.
Purpose:
- To investigate the role of cytokines released by AMs in mineral dust-induced lung fibrosis.
- To determine the effects of AM-derived cytokines on lung fibroblast proliferation and collagen synthesis.
- To explore the potential of cytokine-blocking antibodies in mitigating mineral dust-induced lung fibrosis.
Summary:
- Rabbit AMs cultured with mineral dust (quartz, asbestos, uranium) released increased levels of tumor necrosis factor (TNF) and interleukin-6 (IL-6).
- Supernatants from these stimulated AMs significantly enhanced human fetal lung fibroblast (WI-138) proliferation and collagen synthesis, as measured by 3H-thymidine, 14C-proline incorporation, and hydroxyproline levels.
- Antibodies against TNF and gamma interferon partially inhibited fibroblast proliferation and collagen synthesis, with anti-TNF showing a stronger inhibitory effect on proliferation.
Impact:
- This study elucidates the critical role of TNF and IL-6 in mediating the fibrotic response to mineral dust exposure.
- Findings suggest that targeting TNF and IL-6 signaling pathways could be a therapeutic strategy for preventing or treating mineral dust-induced lung fibrosis.
- Highlights the complex interplay between AMs, cytokines, and fibroblast activity in the pathogenesis of lung fibrosis.
