Objectives: DuraGen, a collagen-based dural graft matrix, is frequently used in clinical neurosurgery. In the present study we examined whether DuraGen influenced neuron survival of or process growth from cerebral cortex neurons in culture.
Methods: Dissociated E19 rat cerebral cortical neurons were cultured at low density on poly-L-lysine or on cryostat-sectioned DuraGen. Neuron survival was assessed using morphological criteria, fluorescein diacetate (FDA) and propidium iodide (PI), nuclear staining and TUNEL labeling. Process growth was analysed using specific antibodies against MAP2 and the 200 kDa neurofilament subunit (NF-H) to identify dendrites and axons, respectively.
Results: In immature cultures (3 days in vitro, DIV), nearly 70% of the neurons remained viable in control and DuraGen-exposed cells. In mature cultures (10 DIV), approximately 45% of the neurons were viable. Survival was similar in DuraGen cultures and controls. Cell viability also was similar when DuraGen conditioned the medium, but was not in contact with the neurons. When 10-day-old cultures were treated with glutamate (100 mumol/l for 24 hours) to elicit excitotoxic injury, a 40% decrease in neuron survival was observed. DuraGen's presence neither exacerbated nor attenuated glutamate-induced excitotoxic neuron death. The amount of necrotic or apoptotic cells also was similar in control and DuraGen cultures. Finally, DuraGen had an equal ability to support both axon and dendrite growth as poly-L-lysine.
Conclusion: Our findings demonstrate that DuraGen has no adverse effect on survival of or process growth from cerebral cortical neurons in vitro. These data support DuraGen's biosafety as a dural substitute in clinical neurosurgery.