Programmed cell death in human acute cutaneous wounds

Resolution of the inflammatory response in acute cutaneous wounds is critic al to healing and delays in this process may lead to impaired wound maturat ion and closure. Apoptotic cells were identified by histological examinatio n of tissue sections and by in situ TdT-mediated dUTP end-labelling of DNA fragments. Apoptotic cells were detected in the dermal inflammatory infiltr ate at the wound margins and in the granulation tissue of 7-day healing wou nds. In 42-day healing wounds a large proportion of the apoptotic cells wer e localised to the mature granulation tissue and to the dermal inflammatory infiltrate under the newly closed epidermis. Apoptotic cells were not dete cted in the epidermis of 7-day and 42-day healing wounds. The percentage of apoptotic cells to the total number of cells in the dermal inflammatory in filtrate of 7-day wounds was 30.5% (26-35%) and 60.7% (range 56-67%) in 42- day healing wounds. The existence of an overall relationship between the nu mbers of apoptotic cells in the 7-day and 42-day healing wounds was determi ned using the Spearman's rank correlation coefficient. Taking all the sampl es into consideration, apoptosis in 7-day wounds was not found to be relate d (r=0.123, p=0.050) to apoptosis in the 42-day healing wounds. This study demonstrates that programmed cell death or apoptosis is responsible for the elimination of the dermal inflammatory infiltrate from healing human cutan eous acute wounds.