Polypropylene mesh seeded with fibroblasts: A new approach for the repair of abdominal wall defects in rats.

PURPOSE: The purpose of study was to develop bioengineered scaffolds by seeding primary mouse embryo fibroblast cells (p-MEF) on polypropylene mesh and to test its efficacy for the repair of abdominal wall defects in rats. METHODS: The study was conducted on 18 clinically healthy adult Wistar rats of either sex. The animals were randomly divided into two equal groups having nine animals in each group. In both the groups a 20mm×20mm size full thickness muscle defect was created under xylazine and ketamine anesthesia in the mid-ventral abdominal wall. In group I the defect was repaired with polypropylene mesh alone and in group II it was repaired with p-MEF seeded polypropylene mesh. Matrices were implanted by synthetic absorbable suture material (polyglycolic acid) in continuous suture pattern. The efficacy of the bio-engineered matrices in the reconstruction of full thickness abdominal wall defects was evaluated on the basis of macro and histopathological observations. RESULTS: Macroscopic observations revealed that adhesions with skin and abdominal viscera were minimum in group II as compared to group I. Histopathological observations confirmed better fibroplasia and collagen fiber arrangement in group II. No recurrence of hernia was found in both the groups. CONCLUSION: Hernias are effectively repaired by implanting polypropylene mesh. However, this work demonstrates that in vitro seeding of mesh with fibroblasts resulted in earlier subsidization of pain, angiogenesis and deposition of collagen, increased thickness of matrices with lesser adhesions with underlying viscera. On the basis of the results p-MEF seeded mesh was better than non-seeded mesh for repair of abdominal wall defects in rats.

Bubaline Cholecyst Derived Extracellular Matrix for Reconstruction of Full Thickness Skin Wounds in Rats.

An acellular cholecyst derived extracellular matrix (b-CEM) of bubaline origin was prepared using anionic biological detergent. Healing potential of b-CEM was compared with commercially available collagen sheet (b-CS) and open wound (C) in full thickness skin wounds in rats. Thirty-six clinically healthy adult Sprague Dawley rats of either sex were randomly divided into three equal groups. Under general anesthesia, a full thickness skin wound (20 × 20 mm(2)) was created on the dorsum of each rat. The defect in group I was kept as open wound and was taken as control. In group II, the defect was repaired with commercially available collagen sheet (b-CS). In group III, the defect was repaired with cholecyst derived extracellular matrix of bovine origin (b-CEM). Planimetry, wound contracture, and immunological and histological observations were carried out to evaluate healing process. Significantly (P < 0.05) increased wound contraction was observed in b-CEM (III) as compared to control (I) and b-CS (II) on day 21. Histologically, improved epithelization, neovascularization, fibroplasia, and best arranged collagen fibers were observed in b-CEM (III) as early as on postimplantation day 21. These findings indicate that b-CEM have potential for biomedical applications for full thickness skin wound repair in rats.

Mesenchymal stem cells-seeded bio-ceramic construct for bone regeneration in large critical-size bone defect in rabbit.

Bone marrow derived mesenchymal stem cells (BMSC) represent an attractive cell population for tissue engineering purpose. The objective of this study was to determine whether the addition of recombinant human bone morphogenetic protein (rhBMP-2) and insulin-like growth factor (IGF-1) to a silica-coated calcium hydroxyapatite (HASi) - rabbit bone marrow derived mesenchymal stem cell (rBMSC) construct promoted bone healing in a large segmental bone defect beyond standard critical -size radial defects (15mm) in rabbits. An extensively large 30mm long radial ostectomy was performed unilaterally in thirty rabbits divided equally in five groups. Defects were filled with a HASi scaffold only (group B); HASi scaffold seeded with rBMSC (group C); HASi scaffold seeded with rBMSC along with rhBMP-2 and IGF-1 in groups D and E respectively. The same number of rBMSC (five million cells) and concentration of growth factors rhBMP-2 (50µg) and IGF-1 (50µg) was again injected at the site of bone defect after 15 days of surgery in their respective groups. An empty defect served as the control group (group A). Radiographically, bone healing was evaluated at 7, 15, 30, 45, 60 and 90 days post implantation. Histological qualitative analysis with microCT (µ-CT), haematoxylin and eosin (H & E) and Masson's trichrome staining were performed 90 days after implantation. All rhBMP-2-added constructs induced the formation of well-differentiated mineralized woven bone surrounding the HASi scaffolds and bridging bone/implant interfaces as early as eight weeks after surgery. Bone regeneration appeared to develop earlier with the rhBMP-2 constructs than with the IGF-1 added construct. Constructs without any rhBMP-2 or IGF-1 showed osteoconductive properties limited to the bone junctions without bone ingrowths within the implantation site. In conclusion, the addition of rhBMP-2 to a HASi scaffold could promote bone generation in a large critical-size-defect.