Intratracheal Administration of Bleomycin via a Catheter in Unanesthetized Rats.

Abstract

Abstract:In order to ensure a widespread distribution in the lung and to avoid the effect of anesthesia, bleomycin at a total dose of 4.5 or 6.0 mg/kg was administered in four divided doses (0.5 ml/kg/time) at intervals of 2 h to male rats via a catheter (tracheotomy tube) without anesthesia. In comparison to vehicle (saline) controls, bleomycin-treated rats showed a significant suppression of body weight gain that was observed transiently at 4.5 mg/kg and continuously (throughout the 3-week observation period) at 6.0 mg/kg. Histopathologically, interstitial pneumonitis, thickening of alveolar walls, thickening of pulmonary arterial walls, foamy cells in alveoli, and hemorrhage were observed in both 4.5 and 6 mg/kg groups, and also emphysema in the 6 mg/kg group. Both groups exhibited a significant decrease in the partial pressure of arterial oxygen (PaO 2 ) and a significant increase in alveolar-arterial oxygen tension difference (AaDO 2 ), and a significant increase in erythrocyte count was observed in the 6 mg/kg group. Furthermore, both treated groups showed a significant increase in the ratio of the right ventricular weight versus left ventricle plus septum weights. The significant increase in erythrocyte count might have been caused by diffusion disturbance and ventilation-perfusion imbalance due to the pulmonary damage. These findings suggest that the present experimental method will be useful for clarification of the pulmonary damage induced by bleomycin in rats. Key words: bleomycin, catheter, diffusion disturbance, erythrocyte count, ventilationperfusion imbalance the precise mechanisms involved in the induction of this disease have not been clarified completely. In rodents, a single intratracheal administration under anesthesia is frequently used for preparing an animal model [7,10,23,26,32], but the extent and severity of pulmonary damage caused by bleomycin varies considerably depending on the attainability of the drug solution [16]. Furthermore, anesthesia itself causes respiratory and

In vivo MRI of altered proton signal intensity and T2 relaxation in a bleomycin model of pulmonary inflammation and fibrosis

“…In addition, we found that, for some of the HD rats, several “abnormal” pixels actually fell to the left of the ellipsoid, indicating that S 0 was lower than control in many pixels. This may be due to the onset of emphysematous alveolar dilation and wall thinning that has been previously observed in bleomycin treated animals (4, 11, 32) and is consistent with proton MRI of emphysema animal models (33, 34). Such emphysematous characteristics were also observed in our histological images (data not shown).…”