Hui Qianru, Zhao Xiaoya, Lu Peng, Liu Shangxi, Nyachoti Martin, O Karmin, Yang Chengbo
Department of Animal Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
Department of Animal Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada; CCARM, St. Boniface Hospital Research Centre, Winnipeg, Manitoba R2H 2A6, Canada.
Poult Sci. 2021 May;100(5):101060. doi: 10.1016/j.psj.2021.101060. Epub 2021 Feb 18.
The extracellular calcium-sensing receptor (CaSR) and vitamin D receptor (VDR) play important roles in regulating calcium mobilization, calcium absorption, and calcium homeostasis, and they could be potential therapeutic targets to osteoporosis in laying hens. The present study investigated the molecular distribution of CaSR and VDR and the localization of CaSR in the kidney, proventriculus (true stomach), duodenum, jejunum, ileum, colon, cecum, shell gland, and tibia of laying hens at 3 different laying stages (19, 40, and 55 wk). The results showed that the relative mRNA abundance of CaSR in the kidney, ileum, proventriculus, duodenum, and colon was higher (P < 0.05) than the other tissues at 40 and 55 wk. The relative mRNA abundance of CaSR in the tibia was higher (P < 0.05) at 55 wk than at 40 wk. However, there were no significant differences in the relative protein abundance of CaSR among all tested tissues at peak production or in each tissue at the 3 different laying stages (P > 0.05). The relative mRNA abundance of VDR was higher (P < 0.05) in the small intestine (duodenum, jejunum, and ileum) when compared with other tissues at the 3 different laying stages. The relative protein abundance of VDR in the duodenum was higher (P < 0.05) than that in the proventriculus, colon, and cecum. There were no significant differences in the VDR expression among the tested tissues at the 3 different laying stages (P > 0.05). The immunohistochemical results showed that the positive staining was found widely in each tissue. Moreover, different laying stages did not affect the localization of CaSR except for the tibia tissue. In conclusion, similar to VDR, CaSR was widely expressed not only in the gut but also in the tibia and shell gland in laying hens. The expression level of CaSR and VDR in all tested tissues was unchanged at the different laying stages.
细胞外钙敏感受体（CaSR）和维生素D受体（VDR）在调节钙动员、钙吸收和钙稳态方面发挥着重要作用，它们可能是蛋鸡骨质疏松症的潜在治疗靶点。本研究调查了3个不同产蛋阶段（19、40和55周龄）蛋鸡的肾脏、腺胃（真胃）、十二指肠、空肠、回肠、结肠、盲肠、蛋壳腺和胫骨中CaSR和VDR的分子分布以及CaSR的定位。结果显示，在40和55周龄时，肾脏、回肠、腺胃、十二指肠和结肠中CaSR的相对mRNA丰度高于其他组织（P<0.05）。55周龄时胫骨中CaSR的相对mRNA丰度高于40周龄时（P<0.05）。然而，在产蛋高峰期所有测试组织中CaSR的相对蛋白丰度，或3个不同产蛋阶段各组织中的CaSR相对蛋白丰度均无显著差异（P>0.05）。在3个不同产蛋阶段，与其他组织相比，小肠（十二指肠、空肠和回肠）中VDR的相对mRNA丰度更高（P<0.05）。十二指肠中VDR的相对蛋白丰度高于腺胃、结肠和盲肠（P<0.05）。在3个不同产蛋阶段，测试组织中VDR的表达无显著差异（P>0.05）。免疫组化结果显示，各组织中均广泛发现阳性染色。此外，除胫骨组织外，不同产蛋阶段不影响CaSR的定位。总之，与VDR相似，CaSR不仅在蛋鸡的肠道中广泛表达，在胫骨和蛋壳腺中也广泛表达。不同产蛋阶段所有测试组织中CaSR和VDR的表达水平均未发生变化。
