PhD Scientific Days 2021

TT_I_P: Theoretical and Translational Medicine I. Posters

Gender specific alterations of carotid artery vascular reactivity in Vitamin D – a rat model

Text of the abstract

The higher cardiovascular risk associated with vitamin D hypovitaminosis is well known, however the effects of vitamin D on the cardiovascular system are less understood.
Our aim was to investigate the early effects of insufficient vitamin D levels on vascular reactivity and assess the sex-related differences in rat carotid arteries.
3-4 weeks old male and female Wistar rats, were divided into four groups according to vitamin D intake. For 8 weeks, half of the male (M) and female (F) animals were provided with optimal vitamin D levels (MD+ N=13; FD+ N=13), while their counterparts were fed with vitamin D deficient chow (MD- N=11; FD- N=11). Phenylephrine (Phe)-induced contraction and acetylcholine-dependent relaxation of carotid rings were studied under normal conditions and under nitric oxide synthase (NOS) and cyclooxygenase (COX) inhibition (L-NAME, INDO) using wire myography. Density of elastic and smooth muscle elements in the vascular walls was assessed resorcin-fuchsin (RF) staining, and immunohistochemical staining for the smooth muscle α-actin (SMA) and endothelial nitrogen-oxide synthase (eNOS).
Gender specific difference in Phe-dependent contraction was observed at 10-6 M Phe concentration, male animals showed significantly stronger contraction. Vitamin D deficiency significantly increased contraction independently from gender. (FD+:113±3,4, FD-:124±3,6, MD+:129±8,3, MD-:154±6)
Inhibition of NOS significantly increased contraction in all groups, INDO pretreatment caused no further change. INDO alone reduced contraction only in the FD+ group.
Ach-dependent relaxation showed a vitamin D independent sex difference: relaxation was significantly lower in male groups compared to females. Vitamin D deficiency failed to induce significant change in this function in both genders. (FD+:74±4,2, FD-:73±5,6, MD+:59±5,7, MD-:51±5)
Based on SMA and RF staining, vitamin D deficiency reduced the density of elastic elements in females and smooth muscle elements in males. Vitamin D deficient male rates showed reduced eNOS immunoreactivity of the carotid artery.
Vitamin D deficiency leads to increased contractile reactivity of the carotid artery in both sexes. Our results suggest that vitamin D deficiency leads to gender specific changes in eNOS expression and elastic and smooth muscle elements density of these vessels.

University and Doctoral School

Semmelweis University, Doctoral School of Theoretical and Translational Medicine