Distribution of Endotracheally Instilled Surfactant Protein SP-C in Lung-Lavaged Rabbits

Abstract

ABSTRACT. In lung-lavaged surfactant-deficient rabbits (n = 6) requiring artificial ventilation, porcine surfactant was instilled endotracheally. This resulted in improvement of lung function so that the animals could be weaned off artificial ventilation. The animals were killed 4% h after surfactant administration and the porcine surfactant protein was localized in the lung with a MAb. We found surfactant protein in all lobes of the lung but the distribution was not homogeneous. Surfactant protein C was found in less than 15% of the alveolar spaces and in less than 1% of the bronchi. The endotracheal instillation of surfactant improves lung function in premature newborn babies with surfactant deficiency. However, the immediate beneficial effects of surfactant therapy are sometimes followed by a relapse several hours later. Factors respc ~sible for the relapse include patency of the ductus arteriosu: : 1) and inhibition of surfactant activity by proteins leaking into the alveolar space (2). Another factor that may be important is the distribution in the lung of the administered surfactant. The distribution of instilled surfactant has been subsequently measured by analysis of different components of instilled surfactant in alveolar wash and in lung tissue (3-7). However, the localization and distribution of the instilled surfactant at the microscopic level in lung tissue has not been reported. In our study, an immunohistochemical technique was used to localize the surfactant-associated protein, SP-C, with the aid of a MAb, after a clinical response. MATERIALS AND METHODSAnimals, the experiments were performed under approved institutional animal care protocols with concern for animal welfare.Healthy 3-mo-old rabbits (n = 12) with a body weight of 2.73 Received February 12, 1990; accepted October 9, 1990. Correspondence: S. Bambang Oetomo, M.D., Department of Pediatrics, Division of Neonatology, University Hospital, Oostersingel 59, 9713 EZ Groningen, The Netherlands.Supported by a grant from the Swedish Heart-Lung Foundation and General Maternity Hospital Foundation (T.C.). 1 + 0.11 kg (mean + SD) were treated as we described before (8).In short: after anesthesia (sodium pentobarbital 30 mg/kg body weight i.v.), the animals were put into the supine position on a heated mattress. the left carotid artery and right jugular vein were cannulated. Subsequently, the animals were intubated by means of a tracheostomy. The rabbits were then paralyzed (pancuronium bromide 0.1 mg/kg body weight) and artificially ventilated (fraction of inspired oxygen 1.0) using an Amsterdam infant ventilator MK I11 (Hoek Loos Co., Schiedam, The Netherlands) set in the volume-controlled mode. Tidal volume was set to 8 mL/kg body weight at a rate of 60 breathslmin. Severe respiratory failure was induced by lung lavage as follows: NaCl 0.9% (35 mL/kg body weight, at a temperature of 38°C) was injected slowly endotracheally and gently withdrawn and this lavage was repeated four times with an interval of 5 min. The total lavage procedure took 25 ...

Decrease in Lung Volume Depends on End-Expiratory Pressure in a Rabbit Model of Airway Lavage

“…Some of the authors aimed at a decrease in C rs by 50% of values before lavage [14, 15, 16, 17], others at a specific level of PaO 2 [12, 18, 19]. A defined number of lavages (between 3 and 10 lavages) has been employed by many groups of investigators [1, 11, 17, 20, 21, 22, 23, 24, 25]. It is difficult to tell from the data of the literature which approach leads to the smallest variance in the decrease in lung volume, change in lung mechanics and impairment in gas exchange.…”