[Morphological tissue changes after the implantation of elastic lamellar foreign bodies in the experiment]

The reaction of rat tissues was studied using the methods of light microscopy 4, 12, 18 days, 1, 2, 6 and 12 months after hypodermic implantation of polymeric films made of polyhydroxyalkanoates (PHA). It was found that polymer, like any foreign matter in an organism, become immediately covered by fibrin. By day 4, there the deformation and destruction of polymeric films were observed due to fibrin contraction. Further, the foreign body was covered by a connective tissue capsule. Under the action of myofibroblasts, the capsule around PHA contracted, thus further deforming and breaking the polymer. Small particles of polymer were covered by macrophages, after some time the cytoplasm of macrophages fused forming the giant cells of foreign body type. After the prolonged period, small fragments of polymeric films were almost completely degraded by macrophages. Large polymeric fragments that were not deformed or crushed, became encapsulated by fibrous tissue and remained unchanged for long time periods.