Transforming Growth Factorhyphen;bgr;1 and Splenocyte Apoptotic Cell Death After Burn Injuries

摘要

NA;Transforming growth factor lpar;TGFrpar;hyphen;bgr;1 is a multifunctional cytokine that mediates apoptotic cell death in human lymphocytes in vitro. To better understand the mechanism through which TGFhyphen;bgr;1 exerts its apoptotic effect, we investigated the role of TGFhyphen;bgr;1 in the relationship between burn injury and cell death of splenocytes in a mouse model of either 0percnt;, 25percnt;, or 40percnt; fullhyphen;thickness burns. Mice were killed and spleens were harvested at 15 and 30 minutes and at 1, 2, 4, 8, 12, and 24 hours after the burn. The spleens were divided and used for both histologic analyses with Hhyphen;E stain and TUNEL stain and for total messenger RNA isolation and reverse transcriptasehyphen;polymerase chain reaction amplification. Amplified polymerase chain reaction products were analyzed for signal strength by electrophoresis. TGFhyphen;bgr;1 RNA expression was highest at 2 hours after the burn injuries in the 40percnt; fullhyphen;thickness burns and at 4 hours after the burn injuries in the 25percnt; fullhyphen;thickness burns. The relative increase in TGFhyphen;bgr;1 RNA was 3 times greater with the larger burn than with the smaller burn. In histologic analysis, splenocyte apoptotic cell death was observed at 4 to 24 hours after the burn in the 40percnt; fullhyphen;thickness burns but at only 4 to 12 hours in the 25percnt; fullhyphen;thickness burns. TGFhyphen;bgr;1 RNA peak expression was observed at different times after the burn in 25percnt; and 40percnt; fullhyphen;thickness burns. Histologic analysis showed apoptotic cell death in proportion with respective messanger RNA expressions. This suggests that TGFhyphen;bgr;1 may be associated with apoptosis of splenocytes in vivo and that the effect of TGFhyphen;bgr;1 after a burn injury may be important in the immune system. lpar;J Burn Care Rehabil 2000semi;21colon;128hyphen;34rpar;