Surfactant proteins B and C are both necessary for alveolar stability at end expiration in premature rabbits with respiratory distress syndrome

Abstract

Modified natural surfactant preparations, used for treatment of respiratory distress syndrome in premature infants, contain phospholipids and the hydrophobic surfactant protein (SP)-B and SP-C. Herein, the individual and combined effects of SP-B and SP-C were evaluated in premature rabbit fetuses treated with airway instillation of surfactant and ventilated without positive end-expiratory pressure. Artificial surfactant preparations composed of synthetic phospholipids mixed with either 2% (wt/wt) of porcine SP-B, SP-C, or a synthetic poly-Leu analog of SP-C (SP-C33) did not stabilize the alveoli at the end of expiration, as measured by low lung gas volumes of approximately 5 ml/kg after 30 min of ventilation. However, treatment with phospholipids containing both SP-B and SP-C/SP-C33 approximately doubled lung gas volumes. Doubling the SP-C33 content did not affect lung gas volumes. The tidal volumes were similar in all groups receiving surfactant. This shows that SP-B and SP-C exert different physiological effects, since both proteins are needed to establish alveolar stability at end expiration in this animal model of respiratory distress syndrome, and that an optimal synthetic surfactant probably requires the presence of mimics of both SP-B and SP-C.

The Influence of Natural Pulmonary Surfactant on The Efficacy of siRNA-Loaded Dextran Nanogels

“…SP-A and SP-D are high molecular weight hydrophilic proteins, that play a role in the innate immune response [12]. In contrast, SP-B and SP-C are small hydrophobic proteins that facilitate formation and stabilization of the surfactant film [13].…”

Properties of modified natural surfactant after exposure to fibrinogen in vitro and in an animal model of respiratory distress syndrome

“…Evaluation of surface activity by CBS. Surface activity of surfactant samples was measured by CBS; developed and built by Schürch and Bachofen (19) as previously described (20,21). The test chamber was initially filled with 10% sucrose in saline.…”

“…The V tissue was calculated by converting the wet weight of the lung into a volume by dividing the wet weight by the specific density of lung tissue. Lung weight and V lung were determined in separate series of experiments and the method is described elsewhere (20,26).…”

Apoptosis and surfactant protein-C expression inhibition induced by lipopolysaccharide in AEC II cell may associate with NF-κB pathway

“…SP-C is lipid membrane-associated and thus probably performs its surface activity in a concerted manner. And it improves surfactant activity in particular interfacial adsorption, film stability and its respreading abilities (Cruz et al, 2000;Serrano and PerezGil, 2006;Wang et al, 1996), and it has been shown that these roles are particularly relevant at extensive lung expansion and relaxation during periods of high ventilatory demands (Almlén et al, 2008). Therefore, this study was designed to evaluate the effects of LPS on its induced apoptosis and SP-C expression inhibiting activity and its possible mechanisms using the primary cultured rat AEC II cells as the experimental model.…”