Granulation Tissue Formation in Subcutaneously Implanted cellulose sponges in young and old Rats

Granulation tissue formation in subcutaneously implanted cellulose sponges has been studied in groups of rats of different age, 2-3 and 14-16 months respectively. The sponges were removed 4, 7 and 14 days after implantation. Assessment of the amount of granulation tissue formed during the implantation period (dry weight) revealed no differences between groups of young and old rats at day 4. At day 7 the old animals exhibited higher values than the young, while at day 14 the situation was reversed, the young animals having the higher values. Breaking strength of the granulation tissue bridging an incision in the sponge was at all post-surgical intervals significantly higher in young than in old animals. The results indicate that the decreased reparative capacity observed in old as compared with young animals is not due to a slower rate of granulation tissue formation, but is rather a consequence of a qualitative differences of the newly formed tissue in the two age groups.