The Effects of Vaccinium myrtillus Extract on Hamster Pial Microcirculation during Hypoperfusion-Reperfusion Injury

Abstract

IntroductionThe present study was aimed to assess the in vivo hamster pial microvessel alterations due to 30 min transient bilateral common carotid artery occlusion (BCCAO) and reperfusion (60 min); moreover, the neuroprotective effects of Vaccinium myrtillus extract, containing 34.7% of anthocyanins, were investigated.Materials and MethodsTwo groups of male hamsters were used: the first fed with control diet and the other with Vaccinium myrtillus supplemented diet. Hamster pial microcirculation was visualized by fluorescence microscopy through an open cranial window. Pial arterioles were classified according to Strahler’s method.ResultsIn age-matched control diet-fed hamsters, BCCAO caused a decrease in diameter of all arterioles. At the end of reperfusion, the reduction of diameter in order 3 arterioles was by 8.4 ± 3.1%, 10.8 ± 2.3% and 12.1 ± 1.1% of baseline in the 2, 4 and 6 month control diet-fed hamsters, respectively. Microvascular permeability and leukocyte adhesion were markedly enhanced, while perfused capillary length (PCL) decreased. The response to acetylcholine and papaverine topical application was impaired; 2’-7’-dichlorofluoresceine-diacetate assay demonstrated a significant ROS production. At the end of BCCAO, in age-matched Vaccinium myrtillussupplemented diet-fed hamsters, the arteriolar diameter did not significantly change compared to baseline. After 60 min reperfusion, order 3 arterioles dilated by 9.3 ± 2.4%, 10.6 ± 3.1% and 11.8 ± 2.7% of baseline in the 2, 4 and 6 month Vaccinium myrtillus supplemented diet-fed hamsters, respectively. Microvascular leakage and leukocyte adhesion were significantly reduced in all groups according to the time-dependent treatment, when compared with the age-matched control diet-fed hamsters. Similarly, the reduction in PCL was progressively prevented. Finally, the response to acetylcholine and papaverine topical application was preserved and there was no significant increase in ROS production in all groups.ConclusionsIn conclusion, Vaccinium myrtillusextract protected pial microcirculation during hypoperfusion-reperfusion, preventing vasoconstriction, microvascular permeability, leukocyte adhesion, reduction in PCL and preserving the endothelium function.

Rat Pial Microvascular Changes During Cerebral Blood Flow Decrease and Recovery: Effects of Cyanidin Administration

“…We characterized the pial microcirculation by fluorescence microscopy to study microvascular responses after acute injury. The alterations caused by the reduction in cerebral blood flow and subsequent reperfusion were characterized by arteriolar constriction, venular permeability increase, leukocyte adhesion to venular walls and capillary rarefaction, as previously reported (Lapi et al, 2016 ; Mastantuono et al, 2016 ). Moreover, we observed a dramatic increase in ROS production, as detected by DCFH-DA assay.…”

“…Moreover, we previously demonstrated the protective effects of Vaccinium myrtillus extract supplementation to the diet (containing 34.7% of anthocyanins) on hamster pial microcirculation during brain hypoperfusion-reperfusion. In particular, after 2, 4, and 6 months of oral supplementation, anthocyanins were able to counteract microvascular changes such as arteriolar vasoconstriction, increase of microvascular permeability and leukocyte adhesion (Mastantuono et al, 2016 ).…”

Laser Speckle Imaging of Rat Pial Microvasculature during Hypoperfusion-Reperfusion Damage

“…BCCAO model was introduced by Eklöf and Siesjö ( 1972 , 1973 ) to cause cerebral transient hypoperfusion in experimental models. BCCAO and reperfusion, indeed, are able to determine significant microvascular alterations, such as arteriolar constriction with altered vasomotor tone, inflammatory processes and extracellular matrix degradation with consequent blood brain barrier disruption and cerebral edema, as previously reported (Lapi et al, 2012 , 2015 , 2016 ; Mastantuono et al, 2015 , 2016b ). Furthermore, these microvascular impairments are accompanied by infarct formation limited to the cortex and striatum, as detected by TTC staining.…”

Dietary Anthocyanins and Stroke: A Review of Pharmacokinetic and Pharmacodynamic Studies

“…A remarkable study was carried out by administering for 2, 4 and 6 months an extract of Vaccinum myrtillus , (Table 4) in golden hamsters with BCCAO (for 30 min) followed by reperfusion (60 min). The ROS, damage area, microvascular leakage, leukocyte adhesion and capillary perfusion were reduced in fed-hamsters with extract by comparison to controls [191].…”