002P London, UK
8th European Workshop on Cannabinoid Research

 

 

Long-term effects of treatment with hypothermia and cannabidiol in developing rats with hypoxic-ischemic brain injury

F. J. Alvarez1, H. Lafuente1, A. A. Alvarez2, M. Revuelta2, O. Arteaga2, W. Hind3, E. Hilario2, J. Martinez-Orgado4. 1Biocruces Institute, Cruces University Hospital, Barakaldo, Spain, 2Cell Biology and Histology, University of the Basque Country, Leioa, Spain, 3GW Research, Histon, Cambridge, United Kingdom, 4Instituto del Niño y del Adolescente (INA), Hospital Clínico "San Carlos" - IdISSC, Madrid, Spain.

Introduction: Hypothermia is the standard treatment for hypoxic-ischemic (HI) newborns, but many treated infants present adverse long-term neurologic outcomes. Cannabidiol (CBD) could act through complementary mechanisms, thus improving the long-term outcomes in rats with experimental HI injury when used in combination with hypothermia1.

Method: 7-day old rats (P7) underwent HI injury2 and were randomized to receive normothermia (N) or hypothermia3 (H), as well as drug treatment with CBD (GW Research, Cambridge UK) 1 mg/kg (C) or its vehicle (V). Animals without brain injury or drug treatment were used as normothermic and hypothermic sham controls (NS, HS). Brain injury was assessed one month later4 (P37) by infarct volume percentage, neuropathological score, glutamate/N-acetyl-aspartate and N-acetyl-aspartate/choline ratios (excitotoxicity and motor outcome), electroencephalography and cognitive deficit (sensori-motor, learning & memory). Data are given as mean ± SEM (n). Analysis was performed using the non-parametric Kruskal-Wallis test with Dunn correction.

Results: Structural, functional and cognitive data from juvenile animals (P37) after treatments are summarized in table 1.

(a) p<0.05 vs. NV group; (b) p<0.05 vs. NC group; (c) p<0.05 vs HV group
Table 1 NS group NV group NC group HS group HV group HC group
Infarct volume percentage
(%)		 0.0±0.0a
(5)		 22.2±0.5
(5)		 14.3±0.3a
(5)		 0.0±0.0c
(5)		 17.2±0.4a,b
(5)		 10.7±0.2a,b,c
(5)
Neuropathological score:
hippocampus		 0.4±0.3a
(10)		 4.0±0.4
(10)		 2.5±0.3a
(10)		 0.2±0.2c
(10)		 3.2±0.2a
(10)		 1.4±0.3a,b,c
(10)
Electroencephalography
(μV)		 19±1a
(10)		 10±1
(10)		 17±2a
(10)		 19±1c
(10)		 14±1a
(10)		 17±1a,c
(10)
Glu/NAA ratio 1.2±0.1a
(5)		 1.8±0.1
(5)		 1.2±0.2a
(5)		 1.0±0.2
(5)		 1.0±0.1a
(5)		 1.0±0.1a
(5)
NAA/Cho ratio 8.5±0.1a
(5)		 3.0±0.2
(5)		 4.4±0.6a
(5)		 9.6±0.1c
(5)		 8.2±0.2a,b
(5)		 9.8±0.3a,b,c
(5)
Rotarod:
latency to fall (sec)		 259±12a
(10)		 95±13
(10)		 217±22a
(10)		 262±10c
(10)		 152±14a,b
(10)		 218±5a,c
(10)
T-maze:
correct response (%)		 64±8a
(10)		 30±5
(10)		 52±10a
(10)		 66±7c
(10)		 37±4
(10)		 56±5a,c
(10)

 

NV group developed a long-lasting functional impairment, as observed in infarct volume, neuropathology, electroencephalography and neurobehavioral tests. NC and HV groups showed improvements, optimized in HC group (combined therapies).

Conclusion: CBD administration to HI newborn rats led to a long-lasting neuroprotection in normothermia, but additional beneficial effects were observed when CBD was given in combination with hypothermia. The study suggests that CBD in combination with hypothermia may improve long-term neurologic outcomes.

References:

1. Lafuente H et al. (2016). Front Neurosci 12: 323.

2. Fernandez-Lopez D et al. (2007). Pediatr Res 62: 255-260.

3. Thoresen M et al. (1996). Arch Dis Child 74: F3-9.

4. Pazos MR et al. (2012).  Neuropharmacology 63: 776-783.