Effectiveness of 1α-25-dihydroxyvitamin D3 active substance on anastomosis safety in the rat femoral artery end-to-end anastomosis experimental model: Macroscopic and histological analyses.

Under inflammatory conditions, macrophage dominance affects the degree of inflammation. We assessed the effects of the active vitamin D (calcitriol) administration on inflammatory processes and macrophage dominance and aimed to determine the potential positive macroscopic and histological effects in supermicrosurgical arterial anastomosis model of rats. Forty rats were divided into five groups: control surgery (Group 1), surgery with preoperative (Group 2), post-operative (Group 3), perioperative (Group 4) systemic calcitriol and surgery with local calcitriol (Group 5). Eighty femoral artery anastomoses were planned in both legs of rats. Systemic calcitriol was administered intraperitoneally daily to the animals in the relevant groups. Preoperative vessel diameter measurements were taken before anastomosis. Three weeks post-surgery, post-operative vessel diameter measurements were taken, anastomosis patency was assessed and vascular segments were collected for histological examination, which included assessment of M1 and M2 macrophage depolarisation, leucocyte infiltration, intima-media ratio and luminal gap scoring. Systemic calcitriol administration (pre-, post- or perioperative) significantly improved the vessel diameter (p < 0.001); there was no significant difference among Groups 2-4. Histological findings revealed that Groups 3 and 4 had lower intima-media ratios (p < 0.05 and p < 0.01), higher M2-M1 macrophage ratios (p < 0.01 and p < 0.001) and lower leucocyte infiltration (p < 0.05, p < 0.01 and p < 0.001). Local calcitriol administration had no vasodilatory effects or resulted in positive histological outcomes. Although the administration of calcitriol pre- and post-operatively increased the vessel diameter, the latter appeared to have a more favourable impact on the histological analyses.

Varenicline increases random flap survival in rats submitted to nicotine.

Smoking is a leading cause of flap failure. Varenicline-assisted smoking cessation has shown beneficial effects on vascular endothelial function. The aim of this study was to determine whether varenicline conveys beneficial effects for skin flap survival. Twenty-four rats were randomly divided into four groups of six. The rats in the control group received normal saline subcutaneous injections, and those in the nicotine group received subcutaneous nicotine injections. The rats in the varenicline group received varenicline intraperitoneally, and those in the nicotine-varenicline group received both nicotine and varenicline. At the end of week 3, the dorsal skin flaps were raised in all rats. On postoperative day 7, the flaps were evaluated by direct observation, microangiography, and light microscopy. The mean necrotic area of the flaps was significantly greater in the nicotine group than in the control group (49.2 ± 4.71 vs. 22.03 ± 0.93%, respectively, p < .01) and significantly higher in the nicotine-varenicline group than in the varenicline group (22.4 ± 1.23 vs. 9.2 ± 0.59%, respectively, p < .01). However, no significant difference was observed between the control and nicotine-varenicline groups (p = .934). Microangiographically, vascularity was lowest in the nicotine group and highest in the varenicline group. Histologically, larger areas of necrosis, more severe inflammation and less vessel formation were observed in the nicotine group. Healing, exhibited by a greater number of vessels, was evident in the varenicline-applied groups. Varenicline appears to increase the microcirculation of random flaps, as shown by decreased flap necrosis and increased vascularity.