Immunohistochemical Demonstration of Vitamin D Receptor Distribution in Goat Intestines

Abstract

Vitamin D (VD) plays an important role in calcium homeostasis. 1,25-Dihydroxycholecalciferol or calcitriol modulates gene transcription via nuclear VD receptors (VDR). In the intestines, VD promotes calcium resorption via VDR. VDR has not been systematically assessed within the intestine in any species. We therefore present a semiquantitative immunohistochemical study of the distribution patterns of VDR in goat intestines. Intestinal tissue probes were collected from 5 lambs and 5 non-lactating non-pregnant dams, fixed in formalin, embedded in paraffin and assessed for VDR. Nuclear VDR immunoreaction was scored semiquantitatively. VDR exhibited a segment-specific distribution pattern. Goblet cells were always devoid of VDR. Enterocytes within the surface epithelium and the superficial crypts generally demonstrated only a weak immunoreaction along the length of the intestine, while basally and/or intermediately located crypt epithelial cells exhibited strong VDR immunoreactions in the duodenum, jejunum and colon descendens. The difference in VDR staining between deep and superficial locations was most prominent in the duodenum and less evident in the jejunum, ileum and colon descendens. Results demonstrate that VDR distribution exhibits cell type-, segment- and location-specific patterns in the goat. Data may serve as a basis for future experiments on the role of VDR in Ca metabolism.

Influence of different calcium supplies and a single vitamin D injection on vitamin D receptor and calbindin D9k immunoreactivities in the gastrointestinal tract of goat kids

“…The results of the present immunohistochemical study in growing goats demonstrated that VDR are present in all intestinal segments, as was also shown in earlier studies (Boos et al, 2007;Liesegang et al, 2008;Riner et al, 2008). The observed VDR-immunoreactivities were prominent in duodenal mucosa, lower in jejunum and colon, further declined in ileum and were lowest in caecum.…”

“…In every tissue specimen, . The semiquantitative evaluation of histochemical reactions for VDR was performed as described previously, i.e., an immunoreactive score (IRS) was calculated for the colored intensity (CI) using this formula (Boos et al, 2007;Liesegang et al, 2008): VDR-IRS = 0 x n(CI 0 ) + 0.25 x n(CI 0,5 ) + 1 x n(CI 1 ) + 4 x n(CI 2 ) + 9 x n(CI 3 ).…”

Vitamin D and the digestive system

“…Semiquantitative immunocytochemical studies with antibodies to vitamin D receptor noted differences in vitamin D receptor staining in goat intestine in segment-and location-specific patterns (49). Changes of enterocyte expression of receptor and function are likely to occur during their migration from crypts to the tip of villi and to hormonal effects during sexual maturation as observed in connection to altered calcium transport in chickens (50).…”

Vitamin D Receptor Expression in Dogs

“…There was only weak VDR expression in the colon in healthy dogs, a finding which is different to people and other species. 39,51 In human ulcerative colitis and in mouse models of colitis, VDR expression is negatively correlated with colonic inflammation.…”