Protective effects of gelsolin in acute pulmonary thromboembolism and thrombosis in the carotid artery of mice

Abstract

The present study provides first evidence on the role of plasma gelsolin in protecting pulmonary thromboembolism and thrombosis in a mouse model. Gelsolin is the most abundant actin depolymerizing protein in plasma and its significantly depleted values have been reported in metabolic disorders including cardiovascular diseases and myocardial infarction. Though gelsolin replacement therapy (GRT) has been shown to be effective in some animal models, no such study has been reported for thrombotic diseases that are acutely in need of bio-therapeutics for immediate and lasting relief. Here, using mice model and recombinant human gelsolin (rhuGSN), we demonstrate the antithrombotic effect of gelsolin in ferric chloride induced thrombosis in carotid artery and thrombin induced acute pulmonary thromboembolism. In thrombosis model, arterial occlusion time was significantly enhanced upon subcutaneous (SC) treatment with 8 mg of gelsolin per mice viz. 15.83 minutes vs. 8 minutes in the placebo group. Pertinently, histopathological examination showed channel formation within the thrombi in the carotid artery following injection of gelsolin. Fluorescence molecular tomography imaging further confirmed that administration of gelsolin reduced thrombus formation following carotid artery injury. In thrombin-induced acute pulmonary thromboembolism, mice pretreated with aspirin or gelsolin showed 100 and 83.33% recovery, respectively. In contrast, complete mortality of mice was observed in vehicle treated group within 5 minutes of thrombin injection. Overall, our studies provide conclusive evidence on the thrombo-protective role of plasma gelsolin in mice model of pulmonary thromboembolism and thrombosis.

Fig 1. Effect of rhuGSN in ferric chloride induced thrombosis in mice on (A) Occlusion time and (B) Blood flow.

Administration of rhuGSN (8 mg/mouse) prolonged the occlusion time and increased blood flow after arterial injury. Data are presented as the median ± SD (n = 6). ***P <0.001, *P <0.05. NS: not significant.

Fig 2

Representative micrographs of H&E-stained carotid artery (A) Normal (sham) carotid artery (B-D) Carotid artery following ferric chloride injury. Section of (B) Vehicle treated group, (C) Heparin (20U/kg) treated group and (D) rhuGSN (8mg/mouse) treated group (Scale bar = 100μm). In rhuGSN treated mice, significantly reduced damage to endothelial and substantially reduced aggregation of platelets was observed.

Fig 3. Fluorescent tomographic imaging of mice (A) Bar diagram representing the quantification of fluorescence (Thrombosis) (B) Fluorescent tomographic imaging of carotid artery (n = 3) probed with AngioSense 750 EX showing a reduction in arterial injury upon pretreatment with rhuGSN.

Images in inset represent 90° view of corresponding 3D geometry of the carotid artery in mice of different groups. Data are presented as the median± SD (n = 3). **P <0.01.

Fig 4. rhuGSN pretreated mice were protected from thrombin-induced thromboembolic mortality.

Mice (n = 6) were pretreated with vehicle, 8 mg/mouse rhuGSN or 75 mg/kg aspirin 30 minutes prior to intravenous injection of 20 IU thrombin. GRT was effective in preventing thrombin-induced thromboembolic death. Data are presented as the median± SD. ***P <0.001.

Fig 5. Effect of rhuGSN on (A) Bleeding time and (B) Platelet count in thrombin-induced acute pulmonary thromboembolism.

Data are presented as the median± SD (n = 6). *P <0.05, **P <0.01, ***P <0.001.

Fig 6. rhuGSN- or aspirin-treated mice were protected from microvascular thrombosis.

Mice were pretreated with vehicle, 8 mg/mouse rhuGSN or 75 mg/kg aspirin 30 min prior to injury with intravenous injection of 20 IU thrombin. Representative H&E stained images of the histological section of (A) normal lung (sham group), (B-D) thrombin-treated. Sections of (B) vehicle treated group, (C) aspirin-treated and (D) rhuGSN treated group, (Scale Bar = 100μm).