Proceedings of The Physiological Society
King's College London (2011) Proc Physiol Soc 22, PC30
Assessing the therapeutic potential of novel lentiviral vector delivery of chondroitinase ABC in adult rats with a spinal contusion injury
K. Bartus1, N. James1, K. Bosch1, C. Kathe1, D. Rowlands1, J. H. Rogers2, E. M. Muir2, E. J. Bradbury1
1. King's College London, London, United Kingdom. 2. University of Cambridge, Cambridge, United Kingdom.
The bacterial enzyme chondroitinase ABC (ChABC) is a promising treatment option for spinal cord injury (SCI), degrading chondroitin sulphate proteoglycans (CSPGs) which are one of the key molecules inhibitory to repair. However, in vivo treatments to date have been suboptimal based on drawbacks such as enzyme stability and invasiveness of previous delivery strategies. Recently, a bacterial chondroitinase cDNA has been engineered that allows the expression and secretion of active chondroitinase enzyme by mammalian cells (Muir et al. 2009). Gene delivery of ChABC may have a number of advantages compared to previous treatment paradigms, including sustained CSPG degradation as well as reduced invasiveness and risk of infection. We have evaluated the effectiveness of lentiviral vector delivery of ChABC in an animal model of spinal contusion injury, which represents the most common form of SCI in humans and, therefore, provides a clinically relevant tool for assessing the efficacy of potential therapeutic interventions. Anaesthetised adult rats (using a mixture of ketamine (60 mg/kg) and medetomidine (0.25 mg/kg), administered i.p.) received a 150kD (Infinite Horizons) contusion injury and lentiviral vector incorporating the ChABC gene or a control GFP was immediately injected rostral and caudal to the injury site. Saline (3-5 ml) and baytril (5 mg/kg) were given subcutaneously twice daily for 3 and 7 days, respectively, post-injury. We have shown prolonged and widespread CSPG degradation with ChABC lentiviral vectors. Additionally, using a number of behavioural, electrophysiological and anatomical outcome measures, we have demonstrated improved function in animals treated with lentiviral ChABC and changes in lesion pathology. We demonstrate the potential advantages of lentiviral vector delivery of ChABC, such as sustained and widespread CSPG degradation that is associated with improved anatomical and functional outcomes.
Where applicable, experiments conform with Society ethical requirements