Figure 3From: Regulation of transplanted mesenchymal stem cells by the lung progenitor niche in rats with chronic obstructive pulmonary diseaseThe increase of MSC homing is associated with collagen fiber deposition. A) normal control group; B) COPD group; C) COPD + 60CO γ irradiation + MSCs transplantation group; D) COPD + rAAV-SPA-TK injection + 60CO γ irradiation + MSC transplantation group; E) COPD + AAV injection + 60CO γ irradiation + MSC transplantation group. (I) Morphological appearance of lung sections stained with Masson’s trichrome (×100) showed hardly any collagen deposition in the normal control group (A). Compared with COPD (B), COPD + 60CO γ irradiation + MSCs transplantation (C), and COPD + AAV injection + 60CO γ irradiation + MSC transplantation (E) groups, there was an obvious increase in collagen deposition around vessels and bronchia in the COPD + rAAV-SPA-TK injection + 60CO γ irradiation + MSC transplantation group (D). Furthermore, blue collagen fibers were found in lung interstitial spaces. (III) The result was expressed as Wac/Pbm (μm2/μm) (collagen area on the basal membrane of airway/the perimeter of the basement membrane of bronchioles.(II, IV) Detection of Y chromosome-specific signals by fluorescent in situ hybridization (FISH) (×200). The nuclei were stained yellow in cells with a Y chromosome (indicated by arrows). These cells were found in groups C, D and E, but more cells were present in group D. The percentage of Y- chromosome positive cells was calculated by the ratio of Y- chromosome positive cells to the total cell number in 5-10 fields at 400× magnification from each section. Increased numbers of MSCs after rAAV-SPA-TK injection suggested that stem cell niches increased the homing of MSCs to the lung. Scale bars = 100 μm. *P < 0.01 compared with the other four groups.Back to article page