Route of exposure influences the cardiovascular effects of Cannabis sativa in salt-induced hypertensive male Wistar rats


Hypertension, Cannabis sativa, blood pressure, aorta


Background: Exposre to Cannabis sativa (CS) has been suggested to exert ameliorative
effects in hypertensive conditions. Using various exposure routes, this study investigated the
likely cardiovascular protective effect of CS in high salt diet (HSD) induced hypertensive male
Wistar rats. Methods: Exposure routes investigated include dietary incorporation
(10%CS+90%HSD), ethanol extract of C. sativa intake (ECS, 3mg/kg p.o.), and inhalation of
C. sativa fumes (1g/day/animal). GC-MS analysis of CS was evaluated, and forty animals were
equally divided into 5 groups as follows; Group I (control) received normal diet, Groups II-V
received HSD alone, CS+HSD, ECS+HSD, and CS fumes+HSD for 28days, respectively.
Thereafter, systolic, diastolic, mean arterial blood pressure, and electrocardiographic readings
were assessed. Haematological analysis of retro-orbital sinus blood samples after light
anaesthesia was also evaluated for full blood cell counts, erythrocyte sedimentation rate,
fibrinogen concentration, and blood viscosity. Aortic samples were harvested for histology.
Resulte: The GC-MS showed Δ9-Tetrahydrocannabinol, Δ9-Tetrahydrocannabivarin,
Cannabidiol and Cannabinol, as prevalent in CS. The HSD only exhibited elevated (P<0.05)
RBC, PCV, haemoglobin, MCV, platelets, WBC, neutrophil, blood viscosity, systolic,
diastolic and mean arterial blood pressure compared to control. CS exposure groups (III-V)
exhibited reduced (P<0.05) RBC, PCV, haemoglobin, WBC, blood viscosity, systolic, diastolic
and mean arterial blood pressure compared to HSD only. However these values were elevated
compared to control. ECG tracings seen in group II suggests myocardial electrical signal
dysfunction while tracings in the CS exposure groups suggest partial amelioration of
myocardial signalling pathways. Histology showed hypertension-induced aortic structural
alterations that were not ameliorated by exposure to CS. Conclusion: Data obtained suggest
that controlled exposure to Cannabis sativa either in diet, as ethanol extract or inhalation may
mediate elevated blood pressure and impaired cardio-electrical signalling in salt (NaCl)-
induced hypertension. However, hypertension-induced cardiac structural and vascular
impairments are not ameliorated by exposure to Cannabis sativa