Young and middle-age associated differences in cytokeratin expression after bone fracture, tissue trauma, and hemorrhage

Background This study examined whether there is any difference in the lung cytokine and cytokeratin 19 levels between young and middle-aged mice after bone fracture and soft-tissue trauma hemorrhage (Fx-TH). Methods Young (6–8 weeks) and middle-aged (12 months) C3H/HeN male mice were subjected to right lower leg fracture, trauma hemorrhage (mean arterial blood pressure to 35 ± 5 mm Hg for 90 minutes), and resuscitation. Results The tumor necrosis factor α level in the lung increased significantly at 2 hours after Fx-TH in both young and middle-aged mice, whereas at 24 hours the levels remained significantly higher in middle-aged mice. Interleukin-6 levels increased significantly 24 hours after Fx-TH in both groups, whereas interleukin-10 levels increased only in middle-aged mice at 24 hours under those conditions. Monocyte chemoattractant protein-1 levels increased significantly 2 hours after Fx-TH. The protein and messenger RNA levels of cytokeratin 19 were significantly higher in middle-aged mice compared with young mice after Fx-TH. Conclusion These results suggest that age influences the lung inflammatory response after Fx-TH.