The objective of the study was to determine the role of vitamin D3(VD3) in regulating adaptation and mechanism of rats to low-phosphorus(P) diets. Rats were assigned to 4 diets containing 0.2%, 0.4%, 0.6%,or 0.8% P co...The objective of the study was to determine the role of vitamin D3(VD3) in regulating adaptation and mechanism of rats to low-phosphorus(P) diets. Rats were assigned to 4 diets containing 0.2%, 0.4%, 0.6%,or 0.8% P consisting of 5 replicate cages with 6 rats per replicate cage and fed for 7 days. Four rats from each replicate cage were treated with ethane-1-hydroxy-1,1-diphosphonicacid, tetrasodium salt(EHDP)and 2 rats remained untreated. Twelve hours prior to preparation on d 7, two of the EHDP-treated rats received an intraperitoneal injection of VD3 [1,25-(OH)_2 D_3] at 600 ng per kg body weight, while two rats did not receive the injection. Rats that did not receive VD_3 injection had decreased(P < 0.001) P absorption, but injection of VD3 resulted in increased(P < 0.001) absorption. The effect of VD3 injection was greater(P < 0.001) for rats fed 0.2% P diet than rats fed 0.8% P diet in ileum. Sodium dependent phosphate cotransporter type IIb(Na/Pi-IIb) and 25-hydroxyvitamin D 1-α hydroxylase(CYP27 B1) mRNA level showed the same trend with P absorption. Serum concentration of VD3 and la-hydroxylase activity in rats fed 0.2% P diet were lower than those fed 0.8% P diet. The injection of VD3 increased(P < 0.001)serum concentration of VD3 and la-hydroxylase activity. Thus, VD3 increased Na/Pi-Ⅱb and CYP27 B1 mRNA level and improved serum concentration of VD3 and la-hydroxylase activity in rats fed low-P diets.展开更多
AIM： To investigate the possible involvement of 25-hydroxyvitamin D3-1cx-hydroxylase [1α-25（OH）2D3] in butyrate-induced differentiation in human intestinal cell line Caco-2 cells. METHODS： Caco-2 cells were incub...AIM： To investigate the possible involvement of 25-hydroxyvitamin D3-1cx-hydroxylase [1α-25（OH）2D3] in butyrate-induced differentiation in human intestinal cell line Caco-2 cells. METHODS： Caco-2 cells were incubated either with 3 mmol/L butyrate and 1 umol/L 25（OH）2D3 or with 1 umol/L 1α-25（OH）2D3 for various time intervals ranging from 0 to 72 h. Additionally, cells were co-incubated with butyrate and either 25（OH）2D3 or 1α-25（OH）2D3. 1α-25（OH）2D3 mRNA was determined semi-quantitatively using the fluorescent dye PicoGreen. Immunoblotting was used for the detection of 1α-25（OH）2D3 protein. Finally, enzymatic activity was measured by ELISA. RESULTS： Both butyrate and 1α-25（OH）2D3 stimulated differentiation of Caco-2 cells after a 48 h incubation period, while 25（OH）2D3 had no impact on cell differentiation. Synergistic effects on differentiation were observed when cells were co-incubated with butyrate and vitamin D metabolite. Butyrate transiently upregulated 1α-25（OH）2D3 mRNA followed by a timely delayed protein upregulation. Coincidently, enzymatic activity was enhanced significantly. The induction of the enzyme allowed for comparable differentiating effects of both vitamin D metabolites. CONCLUSION： Our experimental data provide a further mechanism for the involvement of the vitamin D signaling pathway in colonic epithelial cell differentiation by butyrate. The enhancement of 1α-25（OH）2D3 followed by antiproliferative effects of the vitamin D prohormone in the Caco-2 cell line suggest that 25（OH）2D3 in combination with butyrate may offer a new therapeutic approach forthe treatment of colon cancer.展开更多
基金supported by grants from the Nature Science Foundation (31201810, to M H Cao 31572419, to R J Fang)+1 种基金Education Department of Hunan Province(138039, to M H Cao)Innovation Team Funds Of Hunan Province (to J H He)
文摘The objective of the study was to determine the role of vitamin D3(VD3) in regulating adaptation and mechanism of rats to low-phosphorus(P) diets. Rats were assigned to 4 diets containing 0.2%, 0.4%, 0.6%,or 0.8% P consisting of 5 replicate cages with 6 rats per replicate cage and fed for 7 days. Four rats from each replicate cage were treated with ethane-1-hydroxy-1,1-diphosphonicacid, tetrasodium salt(EHDP)and 2 rats remained untreated. Twelve hours prior to preparation on d 7, two of the EHDP-treated rats received an intraperitoneal injection of VD3 [1,25-(OH)_2 D_3] at 600 ng per kg body weight, while two rats did not receive the injection. Rats that did not receive VD_3 injection had decreased(P < 0.001) P absorption, but injection of VD3 resulted in increased(P < 0.001) absorption. The effect of VD3 injection was greater(P < 0.001) for rats fed 0.2% P diet than rats fed 0.8% P diet in ileum. Sodium dependent phosphate cotransporter type IIb(Na/Pi-IIb) and 25-hydroxyvitamin D 1-α hydroxylase(CYP27 B1) mRNA level showed the same trend with P absorption. Serum concentration of VD3 and la-hydroxylase activity in rats fed 0.2% P diet were lower than those fed 0.8% P diet. The injection of VD3 increased(P < 0.001)serum concentration of VD3 and la-hydroxylase activity. Thus, VD3 increased Na/Pi-Ⅱb and CYP27 B1 mRNA level and improved serum concentration of VD3 and la-hydroxylase activity in rats fed low-P diets.
基金Supported by the Else Kroner-Fresenius Foundation, Bad Homburg, Germany
文摘AIM： To investigate the possible involvement of 25-hydroxyvitamin D3-1cx-hydroxylase [1α-25（OH）2D3] in butyrate-induced differentiation in human intestinal cell line Caco-2 cells. METHODS： Caco-2 cells were incubated either with 3 mmol/L butyrate and 1 umol/L 25（OH）2D3 or with 1 umol/L 1α-25（OH）2D3 for various time intervals ranging from 0 to 72 h. Additionally, cells were co-incubated with butyrate and either 25（OH）2D3 or 1α-25（OH）2D3. 1α-25（OH）2D3 mRNA was determined semi-quantitatively using the fluorescent dye PicoGreen. Immunoblotting was used for the detection of 1α-25（OH）2D3 protein. Finally, enzymatic activity was measured by ELISA. RESULTS： Both butyrate and 1α-25（OH）2D3 stimulated differentiation of Caco-2 cells after a 48 h incubation period, while 25（OH）2D3 had no impact on cell differentiation. Synergistic effects on differentiation were observed when cells were co-incubated with butyrate and vitamin D metabolite. Butyrate transiently upregulated 1α-25（OH）2D3 mRNA followed by a timely delayed protein upregulation. Coincidently, enzymatic activity was enhanced significantly. The induction of the enzyme allowed for comparable differentiating effects of both vitamin D metabolites. CONCLUSION： Our experimental data provide a further mechanism for the involvement of the vitamin D signaling pathway in colonic epithelial cell differentiation by butyrate. The enhancement of 1α-25（OH）2D3 followed by antiproliferative effects of the vitamin D prohormone in the Caco-2 cell line suggest that 25（OH）2D3 in combination with butyrate may offer a new therapeutic approach forthe treatment of colon cancer.
