Network analysis of the left anterior descending coronary arteries in swim-trained rats by an in situ video microscopic technique

Abstract

Background We aimed to identify sex differences in the network properties and to recognize the geometric alteration effects of long-term swim training in a rat model of exercise-induced left ventricular (LV) hypertrophy. Methods Thirty-eight Wistar rats were divided into four groups: male sedentary, female sedentary, male exercised and female exercised. After training sessions, LV morphology and function were checked by echocardiography. The geometry of the left coronary artery system was analysed on pressure-perfused, microsurgically prepared resistance artery networks using in situ video microscopy. All segments over > 80 μm in diameter were studied using divided 50-μm-long cylindrical ring units of the networks. Oxidative-nitrative (O-N) stress markers, adenosine A2A and estrogen receptor (ER) were investigated by immunohistochemistry. Results The LV mass index, ejection fraction and fractional shortening significantly increased in exercised animals. We found substantial sex differences in the coronary network in the control groups and in the swim-trained animals. Ring frequency spectra were significantly different between male and female animals in both the sedentary and trained groups. The thickness of the wall was higher in males as a result of training. There were elevations in the populations of 200- and 400-μm vessel units in males; the thinner ones developed farther and the thicker ones closer to the orifice. In females, a new population of 200- to 250-μm vessels appeared unusually close to the orifice. Conclusions Physical activity and LV hypertrophy were accompanied by a remodelling of coronary resistance artery network geometry that was different in both sexes.

Vitamin-D Deficiency and Supplementation Altered the Network of the Coronary Arteries in a Rodent Model—In Situ Video Microscopic Technique

“…For the technical implementation of our study, we chose the micropreparation and video-microscopic analysis of the LAD branch system [ 39 , 40 , 41 , 42 ]. The technique allows the whole network to be analyzed in its complexity, using physiological pressure conditions to which the blood vessels respond with their own myogenic tone.…”

“…Based on previous work by our research group, we have demonstrated that high blood pressure increases the incidence of these anomalies in the rat LAD network. [ 42 ] In earlier works, we have found that the Murray law of bifurcations was maintained in cases of hypertension, aging and physical exercise [ 39 , 41 ]. In our present study, there was no significant difference between the two groups in terms of the unfavorable coronary anomalies characterizing aged and hypertensive networks [ 42 ].…”

“…Vigantol oil (20,000 IU/mL cholecalciferol suspension) was provided by Merck/Merck Serono (Darmstadt, Germany). For ex vivo video-microscopic analysis, specimens were immersed in normal Krebs–Ringer solution (nKR), which consisted of the substances published in [ 41 ]. The substances used for the nKR were obtained from Reanal (Budapest, Hungary) and Sigma-Aldrich (Sigma-Aldrich, St. Louis, MO, USA–Budapest, Hungary).…”

“…The development of the micropreparation technique of intramural coronary-resistance-artery networks in the rodent model [ 39 , 40 ] and the increasingly widely used technique of video microscopy have made it possible to study the vascular-network system in its complexity and to observe the effect of different variables on the whole network. Our research team successfully demonstrated the effect of hypertension, aging, and training on the entire geometry of the coronary network [ 39 , 41 , 42 ] using this technique.…”

Biofunctionalization of hydrogel-based scaffolds for vascular tissue regeneration

“…One of the main obstacles that tissue engineering must overcome in large-scale clinical applications is the optimal formation of a vascular network that allows the newly created tissue to be easily accepted by the host, and to have network support that allows the perfusion of both oxygen and nutrients and waste elimination (Vu et al, 2022). In this regard, synthesize biomaterials for tissue culture have proven to be excellent for vascular remodeling but their thicknesses of more than 500 µm reduce their application (Ma et al, 2022), as the cells migrate not more than 300 µm from the surface and then they become quiescent due to the low diffusion of oxygen and nutrients (Török et al, 2021).…”