Jornal de Citologia e Histologia

Histological Study on Possible Therapeutic Effect of BM-MSCs on Healing of Lung Fibrosis Induced by CCl₄ with Reference to Macrophage Plasticity

Abstract

Ghada Galal Hamam, Mona H Raafat and Hany KK Mostafa

Background: Lungs are susceptible to several types of toxins. Macrophages may play role in lung fibrosis. Mesenchymal stem cells (MSCs) have several valuable functions that make them a promising therapeutic option in the field of regenerative medicine.

Objectives: Investigate possible therapeutic effects of bone marrow (BM)-MSCs on lung injury induced by carbon tetrachloride (CCl₄) in adult rats with reference to role of macrophages plasticity.

Material and methods: Forty-five adult male albino Wistar rats were divided into four groups. Group I (control). Group II (CCl₄): rats received intraperitoneal injection of CCl₄ (0.1 ml/100 g body weight) twice weekly for two weeks. Group III (BM-MSCs treated) received single injection of BM-MSCs after last injection of CCl₄ and were left for further two weeks. Group IV (recovery): were left for two weeks after last injection of CCl₄. At the end of experiment, all rats were sacrificed. Lung specimens were processed and subjected to H&E, Mallory`s trichrome, CD68, toluidine blue, transmission electron microscope and histomorphometric and statistical studies.

Results: CCl₄ and recovery groups showed thickening of interalveolar septa with mononuclear cellular infiltration, dissolved lamellar bodies in pneumocytes type-II and appearance of foamy macrophages. Significant increase in mean area percentage of collagen fibers, and mean number of CD68 macrophages were also noticed. BM-MSCs improved these histological changes with a significant increase number in pneumocyte type-II.

Conclusions: CCl₄ caused lung injury that was associated with inflammation, increased number of macrophages, and collagen fiber deposition. Treatment with BM-MSCs alleviates these changes and could be used in regenerative medicine.