Gene expression of surfactant protein B and C in endotoxin treated rats

Kim, Yeon Soo; Sohn, Jang Won; Yang, Seok Chul; Yoon, Ho Joo; Shin, Dong Ho; Park, Sung Soo

Abstract

BACKGROUND: The surfactant specific proteins, SP-B and SP-C are thought to be important in regulators of surfactant function and homeostasis. Since systemic sepsis is one common cause of acute respiratory distress syndrome (ARDS) and since abnormalities in surfactant function have been described in ARDS, the authors investigated the effects of endotoxemia on the accumulation of mRNA encoding SP-B and SP-C.
METHODS
Adult rats were given various doses of intraperitoneal endotoxin from Salmonella enteritidis and sacrificed at different time points. Surfactant B and C mRNAs were measured by filter hybridization.
RESULTS
1. SP-B mRNA in 24 hours after 2 mg/kg endotoxin treated group was significantly increased 32.8% comparing to the control group (p<.01). 2. SP-C mRNA in 24 hours after 5 mg/kg and 7.5 mg/kg endotoxin treated group was decreased significantly 38.3% and 36.4% respectively comparing to the control group (p<.001, p<.001). 3. SP-B mRNA in 96 hours after 5 mg/kg endotoxin treated group was significantly decreased 17.3% comparing to the control group (p<.025). 4. In the absence of alterations in the lung wet to dry weight ratios, SP-C mRNA in 6 and 24 hours after endotoxin treated group decreased significantly 29.0% and 26.8% respectively comparing to the control group. SP-C mRNA was 33.3% of control in 144 hours (p<.001) while SP-B was not changed from control.
CONCLUSION
This results indicate that the differential regulation of surfactant proteins in vivo is evident and suggests that surfactant proteins might be differentially regulated during lung inflammation. The functional significance of these alterations remains to be determined.