[Studies on in vivo biocompatibility and biodegradation of absorbable material of polylactic acid]

The biocompatibility and biodegradation of polylactic acid (PLA) made in China were investigated in vivo. A total of 20 implants of PLA in 5 rabbits were studied 2 to 16 months after operation to observe the surrounding tissue reaction, degradation and absorption of PLA. The present results demonstrated that the tissue reaction was mild, and there was a capsule around the implant. It was showed there was a degradation of large molecule of PLA firstly, followed by absorption of PLA. The average degradation rate of PLA molecule was 57.02 per cent and the average weight loss of PLA was 8.15 per cent at the end of eight weeks, but no gross change of contour occurred. The biodegradation was gradual and did not cause an accumulation of lactic acid in the body. The present results demonstrate PLA is a promising implant material in surgery.