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

Abstract

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

Keywords: Hypertension, Cannabis sativa, blood pressure, aorta