Objective To study the expression of connective tissue growth factor (CTGF) and type Ⅱ alveolar cell surface antigen (KL-6) in serum, bronchoalveolar lavage fluid (BALF), and lung tissue of silica treated rats.
Methods Male Wistar rats (n=49) were assigned randomly into control and exposure groups (7, 14, 21, 28, 60, and 90 d after exposure) with seven rats in each group. The exposure groups were instilled with silicon dioxide by non-trachea exposure method (100 mg/mL), and the control group was instilled with sterilized physiological saline. Lung tissues were dissected and serum and BALF were collected. The expression levels of CTGF and KL-6 in the lung tissue samples were determined by immunohistochemistry. The mass concentrations of CTGF and KL-6 in serum and BALF were measured by ELISA.
Results According to the results of immunohistochemistry staining, the exposure groups showed positive CTGF and KL-6 expressions in lung tissues and higher average optical density values than the control group (P < 0.05). In the exposure groups, along with the time after dust exposure increasing, the expression of CTGF showed a pattern of increasing at first and then decreasing with a peak on 28 d (P < 0.05), while KL-6 showed a continuous increase (P < 0.05). The changes of mass concentrations of CTGF and KL-6 in serum and BALF were consistent with those in lung tissues, with the mass concentration of CTGF reaching its peak on 21 d after exposure.
Conclusion CTGF and KL-6 may have a close relationship with pulmonary fibrosis and play a role in the development of silicosis.
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