Time course of membrane microarchitecture-driven neovascularization.
The host response to a microporous material that induces neovascularization at the material-tissue interface was studied in terms of the number and types of cells invading the membrane, the degree of vascularization at the material-tissue interface, and the characteristics of the surrounding connective tissue as a function of time following implantation. Millipore-MF mixed esters of cellulose membranes with a nominal pore diameter of 8.0 microns were implanted subcutaneously into male Sprague-Dawley rats and explanted at 3, 5, 7, 10, 21 and 329 days post-implantation. Two samples from each of two devices at each implantation time were embedded in paraffin, sectioned to a thickness of 5 microns, and stained with haematoxylin and eosin for light microscopic observation. The density of cells in the membrane increased up to 7 days following implantation, then remained roughly constant through 21 days and decreased at the 329 day time point. The vascularity of the material-tissue interface increased up to 10 days and remained at this level even at 329 days post-implantation. The connective tissue was disorganized, loose and avascular at 3 days, resembled granulation tissue at 5 days, and underwent fibrous capsule formation and maturation starting at 7 days following implantation.
Padera
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RF
Division of Health Sciences and Technology, Massachusetts Institute of Technology, Harvard University, Cambridge 02139, USA.
Colton
C K
CK
D000818:Animals; D001672:Biocompatible Materials; D001808:Blood Vessels / Q000166:cytology / Q000254:growth & development; D002482:Cellulose; D015726:Giant Cells / Q000166:cytology / Q000502:physiology; D007249:Inflammation; D008264:Macrophages / Q000166:cytology / Q000502:physiology; D008297:Male; D008567:Membranes, Artificial; D018919:Neovascularization, Physiologic; D019736:Prostheses and Implants; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D001672:Biocompatible Materials; D008567:Membranes, Artificial; D002482:Cellulose