Cannabidiol administration after hypoxia–ischemia to newborn rats reduces long-term brain injury and restores neurobehavioral function
- M.R. Pazosa,
- V. Cinquinaf,
- A. Gómeza,
- R. Layuntaa,
- M. Santosa,
- J. Fernández-Ruizc, d, e,
- José Martínez-Orgadoa, b,
, 
- a Experimental Unit, Foundation for Biomedical Research, Madrid, Spain
- b Neonatology, Department of Pediatrics, University Hospital Puerta de Hierro Majadahonda, Joaquín Rodrigo 1, 28222 Majadahonda, Madrid, Spain
- c Department of Biochemistry and Molecular Biology, Faculty of Medicine, Complutense University, Madrid, Spain
- d Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- e Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- f Universitá degli Studi dell’Insubria, Varese, Italy
Abstract
Cannabidiol (CBD) demonstrated short-term neuroprotective effects in the immature brain following hypoxia–ischemia (HI). We examined whether CBD neuroprotection is sustained over a prolonged period. Newborn Wistar rats underwent HI injury (10% oxygen for 120 min after left carotid artery electrocoagulation) and then received vehicle (HV, n = 22) or 1 mg/kg CBD (HC, n = 23). Sham animals were similarly treated (SV, n = 16 and SC, n = 16). The extent of brain damage was determined by magnetic resonance imaging, histological evaluation (neuropathological score, 0–5), magnetic resonance spectroscopy and Western blotting. Several neurobehavioral tests (RotaRod, cylinder rear test[CRT],and novel object recognition[NOR]) were carried out 30 days after HI (P37). CBD modulated brain excitotoxicity, oxidative stress and inflammation seven days after HI. We observed that HI led to long-lasting functional impairment, as observed in all neurobehavioral tests at P37, whereas the results of HC animals were similar to those of sham animals (all p < 0.05 vs. HV). CBD reduced brain infarct volume by 17% (p < 0.05) and lessened the extent of histological damage. No differences were observed between the SV and SC groups in any of the experiments. In conclusion, CBD administration after HI injury to newborn rats led to long-lasting neuroprotection, with the overall effect of promoting greater functional rather than histological recovery. These effects of CBD were not associated with any side effects. These results emphasize the interest in CBD as a neuroprotective agent for neonatal HI.
Highlights
Keywords
- Cannabidiol;
- Neuroprotection;
- Follow-up;
- Newborn;
- Rats
Abbreviations
- CBD, cannabidiol;
- CRT, cylinder rearing test;
- Epo, erythropoietin;
- HI, hypoxia–ischemia;
- NOR, novel object recognition
Figures and tables from this article:
- Fig. 1. Neurobehavioral tests conducted at P37 in Wistar rats that received an injection of vehicle or 1 mg/kg cannabidiol s.c. after hypoxic-ischemic injury (HV and HC, respectively) or underwent a sham operation (SHM) on P7. Bars represent the mean ± SEM of results from 15 to 23 animals. Photographs on the right are of actual experiments. CRT: cylinder rear test. NOR: novel object recognition. See Methods (2.2. Functional studies) for more details. (*) p < 0.05 vs. SHM.
- Fig. 2. Top: Representative 3D reconstruction of magnetic resonance (MR) images obtained at P37 of Wistar rats that received an injection of vehicle or 1 mg/kg cannabidiol s.c. after a hypoxic–ischemic injury on P7 (HV and HC, respectively). Bottom: Results of the residual lesion volume as calculated from the MR images. See Methods (2.3. Measurement of the extent of brain injury) for more details. Bars represent the mean ± SEM of results from 15 to 23 animals. (*) p < 0.05 vs. sham.
- Fig. 3. Representative micrographs of Nissl staining of brain slices at P14 or P37 from Wistar rats that received an injection of vehicle or 1 mg/kg cannabidiol s.c. after a hypoxic–ischemic injury (HV and HC, respectively) or underwent a sham operation (SHM) on P7. Original magnification: ×200. Scale: 100 μm. Bars in the top graph represent the mean ± SEM of neuropathological score results. See Methods (2.4. Histological evaluation) for more details. (*) p < 0.05 vs. SHM. (§) p < 0.05 vs. HV. (#) p < 0.05 vs. P14.
- Fig. 4. Results from H+-MRS studies carried out on brain samples obtained at P14 or P37 from Wistar rats that received an injection of vehicle or 1 mg/kg cannabidiol s.c. after a hypoxic–ischemic injury (HV and HC, respectively) or underwent a sham operation (SHM) on P7. Bars in the graph represent the mean ± SEM of results from 10 to 15 samples. See Methods (2.5. Proton Magnetic resonance spectroscopy (H+-MRS)) for more details. IPSI: ipsilateral brain hemisphere. CONTR: contralateral brain hemisphere. (*) p < 0.05 vs. SHM. (§) p < 0.05 vs. HV.
- Fig. 5. Results from Western blotting studies carried out on brain samples obtained at P14 from Wistar rats that received an injection of vehicle or 1 mg/kg cannabidiol s.c. after a hypoxic–ischemic injury (HV and HC, respectively) or underwent a sham operation (SHM) on P7. Bars represent the mean ± SEM of results from 5 samples. See Methods (2.6. Western blotting) for more details. (*) p < 0.05 vs. SHM. (§) p < 0.05 vs. HV.
- Corresponding author. Neonatology, Department of Pediatrics, Hospital Universitario Puerta de Hierro Majadahonda, Joaquín Rodrigo 1, 28222 Majadahonda, Madrid, Spain. Tel.: +34 629356330; fax: +34 917913023.
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