Immunohistochemical analysis of apoptosis and cell proliferation in lungs of premature infants with chronic lung disease (bronchopulmonary dysplasia)

Abstract

ABSTRACT Introduction: The pathophisiology of chronic lung disease (CLD), clinically known as bronchopulmonary dysplasia is not clear. It is believed that protective mechanisms, such as the release of inflammatory mediators and the activation of apoptotic and/or proliferative processes are activated in the lung tissue of premature infants in an attempt to repair tissue injury caused by exposure to oxygen and mechanical ventilation. Objective: Assess the presence of apoptosis and cell proliferation in the lungs of premature infants with CLD, exposed to oxygen and/or mechanical ventilation, by analyzing the proteins expression: proliferating cell nuclear antigen (PCNA), phosphatase and tensin homolog (PTEN), B-cell lymphoma 2 (Bcl-2), tumor necrosis factor receptor family member (Fas), fas-associated protein with death domain (FADD), tumor necrosis factor receptor type 1-associated death domain protein (TRADD), Caspase 3 and Caspase 8. Material and methods: We analyzed 32 infants autopsies at gestational age of less than 34 weeks exposed to oxygen therapy. The study was divided into three groups: "classic" CLD, "new" CLD and "without" CLD. Immunohistochemical analysis was performed. Results and discussion: A higher proliferation rate was observed in infants with CLD suggesting that longer exposure to mechanical ventilation may stimulates cell proliferation. The PTEN and Caspase 8 expressions were higher in the "new" CLD group, compared to the "without" CLD group, indicating that the "new" CLD form is more susceptible to apoptosis. Conclusion: Apoptosis and cell proliferation are involved in the pathophisiology of CLD. The "new" CLD form is more susceptible to apoptosis, while cell proliferation is more evident in the groups with CLD.

Keywords

• apoptosis
• pharmacological biomarkers
• cell proliferation
• bronchopulmonary dysplasia
• neonatology