Presented at the Neonatal Society 2006 Widdowson Meeting.

Aquilina K¹, Hobbs CE¹, Tucker AM¹, Thoresen M¹, Whitelaw A²

¹ Clinical Science at South Bristol, University of Bristol, Bristol, UK
² Clinical Science at North Bristol, University of Bristol, Bristol, UK

Objective: Hydrocephalus following intraventricular haemorrhage (IVH) is characterised by deposition of extracellular matrix proteins in the basal cisterns. TGF-β1, 2 and 3 upregulate production of these proteins, and their expression correlates with the degree of PHVD in rat pups (1). Their cerebrospinal fluid concentration in preterm neonates with IVH also correlates with later shunt dependence (2). We have used Pirfenidone, a TGF- β suppressor, in a rat pup IVH model to determine whether PHVD can be reduced.

Method: The study was undertaken in accordance with UK ethical guidelines. Seven-day old Wistar rat pups were fully anaesthetised. Blood with an elevated haematocrit was sequentially injected in both lateral ventricles (3). 45 pups were randomised; 23 received pirfenidone solution (in water) by gavage at 300mg/kg/day in two doses for 14 days; this was the maximal dose tolerated by neonatal animals from the same inbred strain in an in-house dose response study. 22 animals received similar volumes of water (water group) in the same manner. 28 control pups did not undergo IVH, but were given water by gavage as in the IVH animals. All animals underwent behavioural testing along three protocols (negative geotaxis, grip traction and spontaneous movement) on postnatal days 12, 14, 18 and 21. Cardiac perfusion under deep halothane anaesthesia was performed on day 21. 3mm-thick coronal brain blocks were obtained; each block was photographed and the ventricular area in each block determined using image analysis software (QWin, Leica Microsystems, Cambridge). Total ventricular area in the blocks was expressed as a composite value.

Results: There was no signif icant difference between the two IVH groups (p = 0.60, Mann Whitney U test). Median composite ventricular area was 6.7 mm² (interquartile range 4.06-9.34) in the animals receiving pirfenidone and 6.0 mm² (4.03-9.49) in the IVH group receiving water; values for the non- IVH controls were 1.79 (1.03-2.98). No significant difference in final body weight or in any of the behaviour testing protocols was evident between the two IVH groups; control animals performed better on the negative geotaxis test on PN 14. Comparison of the composite ventricular area between the IVH and the control groups showed that 90% of the IVH animals developed ventricular dilatation.

Conclusion: Although increased expression of TGF-β’s has been correlated with deposition of extracellular matrix proteins and PHVD, TGF-β suppression has not prevented PHVD in this model. This may suggest that additional factors are relevant to the development and maintenance of PHVD.

References
1. Cherian S, Thoresen M, Silver IA, Whitelaw A, Love S. Neuropathol App Neurobiol 2004;30:585-600.
2. Whitelaw A, Christie S, Pople I. Ped Res 1999; 46:576-580.
3. Cherian SS, Love S, Silver IA, Porter HJ, Whitelaw AGL, Thoresen M. J Neuropath Exp Neurol 2003; 62:292-303.