ABSTRACT: Hypertension poses a significant global health burden and is closely associated with cardiovascular morbidity. Pistacia lentiscus var. chia, commonly known as mastic, has emerged as a potential nutraceutical, due to its diverse pharmacological properties, including antioxidant and vasodilatory effects. Yet, its impact on hypertension in translational in vivo models and on hypertension-associated abnormalities in circulation, vasculature and kidneys have not been investigated. Herein we sought to decipher the putative antihypertensive potential of mastic, focusing on vascular and renal endothelium in clinically relevant in vivo models of essential hypertension. Two translational in vivo models of hypertension induced by Angiotensin II and Deoxycorticosterone acetate (DOCA)-High Salt in male rats, were utilized. Mastic administration at a therapeutic dose (220mg/kg, per os) was administered daily for four weeks, after the establishment of hypertension. Non-invasive blood pressure measurements and whole blood RNA sequencing and metabolomics were performed. Real-time PCR and Western blot analysis were conducted in kidney and aorta, to decipher its underlying antihypertensive mechanism. Mastic administration significantly reduced systolic, diastolic, and mean blood pressure in both in vivo hypertensive models. RNA sequencing revealed distinct gene expression profiles, with modulation of immune-related pathways in the Angiotensin II model and metabolic pathways in the DOCA-HS model. Additionally, RNA sequencing analysis revealed that mastic downregulated Rhob, Jun, Txnip and Egr1 mRNA expression in the circulation, paving towards a putative antioxidant and endothelial-targeted mechanism. Metabolomic analysis identified lysophosphatidylinositol upregulation as a consistent effect of mastic in both in vivo models, being implicated with improved endothelial homeostasis. RT-PCR analysis in the kidneys and aorta, showed that mastic increased endothelial markers such as Vegfa and Egr-1 mRNA expression in both experimental models. Concerning the endothelial homeostasis, mastic additionally increased renal nitric oxide synthase phosphorylation in both in vivo models of hypertension. This study highlights the potential of mastic as a natural adjuvant therapy for hypertension. The findings shed new light on its molecular mechanisms of action, providing insights into its protective impact on renal endothelium.
