[The changes in the pulmonary surface tension and the tissue content of surfactant substance protein B during early post-injury stage in rabbits inflicted with smoke inhalation injury].

OBJECTIVE: To investigate the changes in the pulmonary surface tension and the tissue content of surfactant substance protein B (SP-B) in rabbits during early post-injury stage after smoke inhalation injury. METHODS: Thirty-two healthy rabbits inflicted with smoke inhalation injury were employed in the study as injury group, and they were sacrificed at 0.5, 2.0, 6.0, 12.0 post injury hours (PIH), with 8 rabbits at each time point. Another 8 rabbits were assigned to normal control group. The pulmonary tissue samples of the rabbits in each group were harvested for the collection of bronchial-alveolar lavage fluid (BALF). The changes in maximal tension (Tmax), minimal tension (Tmin) and hysteresis square (HS) of BALF were measured after the addition of 0.5, 1.0 and 3.0 ml of SP-B antibody into the BALF of the rabbits in each group. The changes in SP-B and SP-B mRNA contents in rabbit pulmonary tissue of each group were assessed with immunohistochemistry and in situ hybridization techniques, respectively. RESULTS: There was no obvious difference in Tmax in BALF of each group or at each time point before and after the action of different concentrations of SP-B antibody in BALF (P > 0.05). But the Tmin in injury group at 2, 6 and 12 PIH was much higher than that before the addition of the antibody (P < 0.05). And the change in HS was similar to that in Tmin. The SP-B content in alveolar type II epithelial cells (AT-II) was decreased significantly at 2, 6 and 12 PIH, whereas the expression in SP-B mRNA exhibited no change. CONCLUSION: There was no obvious change in SP-B synthesis by AT-II in the lung tissue of the rabbits inflicted with smoke inhalation injury during early post injury stage. The increase of SP-B secretion from AT-II cells might be beneficial to the early protection of pulmonary tissue of the rabbits with smoke inhalation injury.