Does tamoxifen citrate prevent pulmonary fibrosis due to silica inhalation?

As shown in several studies, besides being used in breast cancer, tamoxifen is also known for its antifibrotic effects via reducing the serum TGF-beta levels. We investigated the possible preventive effect of tamoxifen in rats exposed to silica particles depending on the antifibrotic effect.

A total of 102 adult female Wistar Albino rats were divided into five groups. First two groups (control and tmx) were free of silica and the last three groups (slc, tmx1 and tmx 10) were exposed to crystalline silica. The rats in tmx, tmx1 and tmx10 groups received 10 mg/kg, 1 mg/kg and 10 mg/kg of body weight tamoxifen, respectively. On day 84, all rats were sacrified and tissue samples were obtained together with blood samples. The differences in serum TGF-β levels, histological grades of fibrosis and inflammation in the lung and liver tissues together with addional biochemical markers were calculated between the groups.

Silicosis occurred in slc, tmx1 and tmx10 groups in 100%, 91.7% and 52.1%, respectively. Liver fibrosis did not occur. The highest mean lung fibrosis scores were obtained in slc group while the scores were lower in tmx1 group and the lowest in tmx10 within silica-exposed rats. Nevertheless, the inflammation scores were higher in tamoxifen-administered rats in a dose-dependent pattern.

Silica inhalation did not result in liver fibrosis. Tamoxifen is found to prevent lung fibrosis and reduce serum TGFβ-1 levels while increasing lung inflammation (Tab. 3, Fig. 3, Ref. 27).