Evaluation of histological changes after tracheal occlusion at different gestational ages in a fetal rat model

• Published in: Clinics (São Paulo, Brazil) Vol. 68; no. 1; pp. 59 - 63
• Main Authors: Gallindo, Rodrigo Melo, Gonçalves, Frances Lilian Lanhellas, de Resende Barreto, Carolina Teixeira, Schmidt, Augusto Frederico Santos, Pereira, Luis Antonio Violin Dias, Sbragia, Lourenço
• Format: Journal Article
• Language: English; Portuguese
• Published: Brazil Elsevier España, S.L.U 2013; Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; Faculdade de Medicina / USP; Elsevier España
• Subjects: Age Factors; Animals; Basic Research; Body Weight; Diaphragmatic; Experimental Model; Fetus - anatomy & histology; Fetus - embryology; Fetus - surgery; Gestational Age; Hernia; Lung - anatomy & histology; Lung - embryology; MEDICINE, GENERAL & INTERNAL; Models, Animal; Organ Size; Rats; Reproducibility of Results; Therapeutic Occlusion; Therapeutic Occlusion - adverse effects; Therapeutic Occlusion - methods; Time Factors; Trachea; Trachea - anatomy & histology; Trachea - embryology; Trachea - surgery; Hernia; Therapeutic Occlusion; Rats; Diaphragmatic; Experimental Model; Trachea
• ISSN: 1807-5932; 1980-5322; 1980-5322
• DOI: 10.6061/clinics/2013(01)OA09

To evaluate the histological changes of tracheal cartilage and epithelium caused by tracheal occlusion at different gestational ages in a fetal rat model. Rat fetuses were divided into two groups: a) External control, composed of non-operated rats, and b) Interventional group, composed of rats operated upon on gestational day 18.5 (term = 22 days), divided into triads: 1) Tracheal occlusion, 2) Internal control and 3) Sham (manipulated but not operated). Morphological data for body weight, total lung weight and total lung weight/body weight ratio were collected and measured on gestational days 19.5, 20.5 and 21.5. Tracheal samples were histologically processed, and epithelial, chondral and total tracheal thicknesses were measured on each gestational day. The tracheal occlusion group exhibited an increase in total lung weight/body weight ratio (p<0.001). Histologically, this group had a thicker epithelial thickness (p<0.05) and thinner chondral (p<0.05) and total tracheal thicknesses (p<0.001). These differences were more prominent on gestational days 20.5 and 21.5. Tracheal occlusion changed tracheal morphology, increased epithelial thickness and considerably decreased total tracheal thickness. These changes in the tracheal wall could explain the development of tracheomegaly, recently reported in some human fetuses subjected to tracheal occlusion.