title: Role of bone marrow and mesenchymal stem cells in healing after traumatic injury.
abstract: BACKGROUND
  The role of bone marrow-derived cells (BMDCs) and mesenchymal stem cells (MSC) in healing of traumatic-induced injury remains poorly understood. Mesenteric lymph duct ligation (LDL) results in decreased BMDC mobilization and impaired healing. We hypothesized that LDL-mediated impaired healing would be abrogated by reinjection of BMDC or MSC.
  
  
  METHODS
  Sprague-Dawley rats were subjected to LDL + lung contusion (LC+LDL) with or without injection of BMDCs or MSCs. Unmanipulated control (UC) and lung contusion alone (LC) served as controls. BMDC and MSC homing was assessed by hematopoietic progenitor cell (HPC [granulocyte-, erythrocyte-, monocyte-, and megakaryocyte colony-forming units; erythroid burst-forming units; and erythroid colony-forming units]) colony growth and immunofluorescent microscopic tracking of tagged MSC, respectively. Histologic lung injury score (LIS) was used to grade injury. Data are mean ± SD. *P < .05/Student t test.
  
  
  RESULTS
  Lung HPC growth was decreased in LC+LDL versus LC alone (HPC colonies: 2 ± 2, 4 ± 3, 4 ± 2 vs. 11 ± 2, 20 ± 6, 22 ± 9. *P < .05). LC+LDL had greater degree of lung injury on days 5 and 7 LC alone (LIS: 5 ± 1, 4 ± 1 vs. 3 ± 1, 1 ± 0.4. *P < .05). BMDC injection into rats with LC + LDL increased lung HPC growth to LC level (HPC colonies: 12 ± 2, 19 ± 5, 17 ± 4 vs 11 ± 2, 20 ± 6, 22 ± 9. P > .05). Injected MSCs into LC+LDL rats homed preferentially to contused versus noncontused lung (MSC/high-powered field: 6 ± 4 vs. 2 ± 2 *P < .05). Either BMDC or MSC injection into LC+LDL rats returned lung injury to LC level on day 7 (LIS: 1 ± 0.4 and 1 ± 1 vs. 1 ± 0.4. P > .05).
  
  
  CONCLUSIONS
  LDL-mediated impaired tissue healing is abrogated by either whole BMDC or MSC injection. This highlights the critical role of BMDC and MSC on healing of trauma-induced injury.
authors.affiliation: University of Medicine and Dentistry of New Jersey-New Jersey Medical School, 150 Bergen Street, Newark, NJ 07103, USA.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Hannoush
authors.forename: Ihab
authors.initials: I
authors.lastname: Elhassan
authors.forename: Ziad C
authors.initials: ZC
authors.lastname: Sifri
authors.forename: Alicia A
authors.initials: AA
authors.lastname: Mohr
authors.forename: Walter D
authors.initials: WD
authors.lastname: Alzate
authors.forename: David H
authors.initials: DH
authors.lastname: Livingston
mesh_terms: D055371:Acute Lung Injury / Q000601:surgery; D000818:Animals; D001854:Bone Marrow Cells / Q000502:physiology*; D016026:Bone Marrow Transplantation; D003288:Contusions / Q000601:surgery; D006412:Hematopoietic Stem Cells / Q000502:physiology; D008026:Ligation; D042601:Lymphatic Vessels / Q000601:surgery; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D008643:Mesentery; D051381:Rats; D017207:Rats, Sprague-Dawley; D014945:Wound Healing / Q000502:physiology*