Cryopreserved human amniotic membrane for soft tissue repair in rats

Fresh amniotic membrane has been used in medicine since 1910. The reconstruction of immunologic privileged ocular surfaces with cryopreserved amniotic membrane was introduced in the 1990s. The aim of this study was to analyze the use of cryopreserved human amniotic membrane (HAM) as a surgical patch in immunologic unprivileged anatomic sites. In part I of the investigation, the abdominal wall muscle of 36 rats was covered with mono- and multilayered HAM. After 3, 14, and 28 days, respectively, these grafts were evaluated macro- and microscopically. Multilayer samples displayed slower degradation and less inflammation compared with monolayer coverage. In part II of the study, abdominal wall closure with multilayer HAM and with polypropylene mesh was conducted in 20 rats. All rats showed sufficient closure after 21 days, but significantly lower intraabdominal adhesion formation was observed in the HAM rats. The results of this study might pave the way for the use of cryopreserved HAM as graft material in reconstructive surgery.