Data_Sheet_1_Expression of vitamin D receptor, CYP24A1, and CYP27B1 in normal and inflamed canine pancreases.DOCX

Vitamin D plays a role in anti-inflammatory processes, and the alteration of its metabolism is associated with the inflammatory processes of pancreatitis. This study was performed to evaluate the expression of the vitamin D receptor (VDR) and the two major enzymes that regulate vitamin D metabolism, 1α-hydroxylase (CYP27B1) and 24-hydroxylase (CYP24A1), in the canine pancreas and to compare their degrees of immunoreactivity between normal and inflamed pancreases. Five normal and inflamed pancreatic tissues each were obtained from six dogs. The expression of VDR, CYP24A1, and CYP27B1 were determined immunohistochemically, and the degree of immunostaining was assessed semiquantitatively. The VDR was expressed in the ducts, acini, and islets of Langerhans of normal pancreases and in the ducts and acini of inflamed ones. There was a significant difference in the immunoreactivity score for VDR in the islets of Langerhans between normal (median, 3 [interquartile range, 2–7.5] score) and inflamed pancreatic tissues (0 [0–0.5] score, p = 0.03). CYP24A1 was expressed in the ducts and islets of Langerhans in both normal and inflamed pancreases, whereas CYP27B1 was expressed in the ducts and acini in only some normal and inflamed pancreatic tissues. This study showed that VDR expression decreased in inflamed pancreases and demonstrated CYP24A1 and CYP27B1 expression in the canine pancreas for the first time. These findings indicate that the pancreas could regulate the metabolism and biological activity of vitamin D and suggest that a decrease in these might be related to the pathophysiology of pancreatitis.

维生素D（Vitamin D）参与抗炎进程，其代谢异常与胰腺炎的炎症进程密切相关。本研究旨在评估维生素D受体（vitamin D receptor, VDR）以及两种调控维生素D代谢的关键酶——1α-羟化酶（1α-hydroxylase, CYP27B1）和24-羟化酶（24-hydroxylase, CYP24A1）在犬胰腺中的表达情况，并比较正常胰腺与炎性胰腺的免疫反应性程度。本研究从6只实验犬体内分别采集5份正常胰腺组织与5份炎性胰腺组织，采用免疫组织化学法检测VDR、CYP24A1及CYP27B1的表达水平，并通过半定量法对免疫染色强度进行评分。结果显示，正常胰腺的导管、腺泡及胰岛中均有VDR表达，而炎性胰腺组织仅在导管与腺泡中检测到VDR表达。正常胰腺胰岛的VDR免疫反应评分（中位数为3，四分位距2~7.5）与炎性胰腺组织（中位数为0，四分位距0~0.5，p=0.03）之间存在显著统计学差异。CYP24A1在正常与炎性胰腺的导管及胰岛中均有表达，而CYP27B1仅在部分正常及炎性胰腺组织的导管与腺泡中存在表达。本研究首次在犬胰腺中证实了CYP24A1与CYP27B1的表达，并发现炎性胰腺组织中VDR的表达水平显著降低。上述研究结果表明，胰腺可调控维生素D的代谢与生物学活性，提示此类蛋白表达水平的降低可能与胰腺炎的病理生理机制相关。