Bruised Tissue. I. Biochemical Changes Resulting from Blunt Injury.

In experimentally inflicted bruises of cattle, the greatest swelling and fluid volume occurred within 2 days. The maximum biochemical changes in bruised tissue were found on or about the fourth or fifth day: These included a drop in N.P.N. to one-fourth of the control level and a 2-fold increase in the “easily split iron” concentration. Moreover, the 10-fold elevation in red pigment was due to extra-stromal hemoglobin. Bilirubin formation in bruised tissue has been demonstrated conclusively and the probable metabolic derivation of this pigment is discussed. Although healing was evident grossly in 7 days, the biochemical values did not return completely to the control levels until the ninth day.