Figure 4: Alkaline phosphatase activity increases in CP chondrocytes culture in chitosan sponges. CP and CD chondrocytes were cultured in chitosan sponges for 5 and 10 days, ALP activity was measured spectrophotometricaly, and normalized to the total DNA content of each sample. ALP activity exponentially increased in CP chondrocytes, while in CD chondrocytes, no significant changes where observed. *Significant difference from CP chondrocytes at day 5. **Significant difference from CD chondrocytes day 10.