The effect of enoxaparin on bleomycin-induced lung injury in mice.

We have evaluated the effect of enoxaparin, a potent antithrombotic drug, on bleomycin (Bleo)-induced pulmonary inflammation in mice. Pulmonary injury was induced by a single intratracheal (i.t.) instillation of Bleo. Four groups of female C57BL/6 mice, each received one of four treatments: (1) i.t. Bleo and daily intraperitoneal (i.p.) injections of enoxaparin (EN) starting one day before i.t. instillation of Bleo (Bleo-EN); (2) i.t. Bleo and i.p. injections of saline (Bleo-Sal); (3) i.t. saline and i.p. enoxaparin (Sal-EN); (4) i.t. saline and i.p. saline (Sal-Sal). Animals were sacrificed 14 days after i.t. treatment. Lung injury was evaluated by analysis of bronchoalveolar lavage fluid and histologically by an overall semiquantitative index of lung injury and a quantitative image analysis assessing alveolar wall area fraction and fibrosis fraction. Treatment of mice with enoxaparin did not ameliorate Bleo-induced lung injury. Our study does not establish a critical role of procoagulant activity in the evolution of Bleo-induced lung injury and does not support the use of antithrombotic therapy for the prevention of pulmonary fibrosis.