BACKGROUND:The internal structures of the colagen-heparan sulfate scaffold and human nerve are very similar. OBJECTIVE: To explore thein vivo biocompatibility of colagen-heparin sulfate scaffold. METHODS:Forty pigs were randomly divided into two groups, 20 in each group: observation group and control group. Medulo-puncture needle was inserted 1.0 cm adjacent to the midline of anterior fontanele into the subarachnoid space, and then removed gradualy. Colagen-heparin sulfate scaffold was implanted into the observation group, and no treatment was given in the control group. Brain tissues were observed under transmission electron microscope, and cel apoptosis and Caspase-3 expression were detected at days 1, 3, 7, 14 and 30 after surgery. RESULTS AND CONCLUSION:Under the electron microscope, there were some damaged neurons in the observation group with the emergence of demyelination changes in the myelinated nerve fibers; positiveexpression of Caspase-3 protein was found at the junction between the brain tissue and scaffold as wel as within the scaffold, but no positive expression was found in the surrounding tissue. There was no cel apoptosis within 30 days after surgery except for individual apoptotic neurons both in the observation group and control group. The number of apoptotic cels in the observation group was higher than that in the control group at days 1, 3, 7, 14 days after surgery (P < 0.05), but there was no difference between the two groups at 30 days after surgery (P > 0.05). Caspase-3 protein expression was at a low state in the two groups, but the protein expression of Caspase-3 was higher in the observation group than the control group at days 3 and 7 after surgery (P < 0.05). These findings indicate that the colagen heparin sulfate scaffold has good biocompatibility in the porcine brain.