Reduced adhesion of blood cells to biodegradable polymers by introducing phosphorylcholine moieties.

Aliphatic polyesters are believed to be good biocompatible polymers for tissue engineering because of their biodegradability and nontoxicity of the degradated products. However, it is necessary to reduce the nonspecific protein adsorption for the application of biodegradable polymers to drug delivery systems or antiadhesive membranes. We hypothesized that novel biodegradable polymers could be synthesized by introducing phosphorylcholine moieties into aliphatic polyesters.

Ischemic injury and repair process after transection in hypothyroid rat muscles.

Hindlimb ischemia for 4 h, followed by reperfusion, resulted in necrosis of most soleus muscle in euthyroid rats, whereas only slight damage occurred in hypothyroid rats. Muscle repair after transection of the tibialis anterior muscle of hypothyroid rats showed delayed debris removal, initial retardation of myotube formation, and a higher incidence of aberrant sarcomeres in newly formed muscle fibers by electron microscopy. The protective mechanism against ischemia in hypothyroid muscles can probably be attributed to decreased degradation of high-energy phosphates, reduced formation of substrates for xanthine oxidase during ischemia, and attenuated generation of harmful oxygen free radicals during reperfusion.