Application of cryoirradiation-modified xenopericardium for building bladder wall defect

The project goal was to study special aspects of biointegration and the functional efficiency of the modified xenopericardium on the experimental model in vivo. Xenopericardium devitalization was performed using low temperatures and ionizing radiation (β--radiation) in an original manner.

In rabbits, a urinary bladder (UB) wall defect was repaired through tissue replacement. Observation period: up to 1 year. After implantation, tissue reaction and biomaterial structure changes were studied using light and electron microscopy. Dynamic ultrasound diagnostics were performed.

After surgery all animals displayed normal physiological activity. No cases of material rejection or postoperative period complications were detected. At all stages the xenopericardium preserved structural integrity and served as a skeleton for forming an adequate UB wall. Small peripheral areas were exposed to lysis. After 3 months the collagen structure of the graft was rearranged and mucous membrane epithelization appeared. Folding was already formed and invasion of narrow SMC panniculi was registered within deeper layers. After 6 months the inner surface of the UB wall consisted of normal mucosa, lined by fully formed epithelium. By the 7th month an almost solid muscular sheet was formed in the lower layers.

Modified pericardium tissue with the given physical and mechanical properties was sustainable and able to endure the work load in an aggressive environment. It causes minimal inflammatory response, has a potential for cellular repopulation in vivo, stimulates formation of fibrous tissue, and embedded and restored cellular integrity and UB storage function.