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目的探讨小肠黏膜上皮斯钙素-1(STC1)基因表达与质膜Ca2+-ATP酶活性的关系。方法基于耐受实验结果,将72只成体中华大蟾蜍随机分为高钙环境组(加0.1 mol/L CaCl2的自来水)、低钙环境组[加0.03mol/L乙二胺四乙酸(EDTA)的自来水]及正常对照组(自来水),分别于暴露前及暴露后12h、24h、48h、72h、96h、120h、144h取血浆和小肠黏膜,利用比色法和半定量RT-PCR法分别检测血浆钙水平、质膜Ca2+-ATP酶活性和STC1 mRNA表达水平。结果 0.1mol/L氯化钙暴露致中华大蟾蜍血浆钙水平在12h和24h时显著高于对照组水平(1.9mmol/L)(P<0.05),48h时回复至正常,72h后持续升高;而12～48h内小肠黏膜上皮质膜Ca2+-ATP酶活性增强和STC1 mRNA水平上调,72h后回复至正常水平。0.03mol/L EDTA暴露则使中华大蟾蜍血浆钙水平下降,但质膜Ca2+-ATP酶活性和STC1 mRNA水平与对照组相比未出现明显变化。结论血浆钙水平升高致小肠黏膜上皮质膜Ca2+-ATP酶活性升高,进而增强STC1表达,而STC1表达上调又以负反馈方式抑制质膜Ca2+-ATP酶的活性。
Objective To investigate the relationship between the expression of stasolin-1 (STC1) gene in small intestinal mucosa and plasma membrane Ca2 + -ATPase activity. Methods Based on the results of tolerance test, 72 adult Bufo gargarizans were randomly divided into high calcium group (0.1 mol / L CaCl2 tap water), low calcium group [plus 0.03 mol / L ethylenediaminetetraacetic acid (EDTA) (Tap water) and normal control group (tap water). The plasma and small intestine mucosa were taken before and 12h, 24h, 48h, 72h, 96h, 120h and 144h after exposure respectively and detected by colorimetric and semi-quantitative RT-PCR Plasma calcium level, plasma membrane Ca2 + -ATPase activity and STC1 mRNA expression level. Results Plasma calcium level in Bufo bufo gargarizans exposed to 0.1 mol / L calcium chloride was significantly higher than that in control group (1.9 mmol / L) at 12 h and 24 h (P <0.05), returned to normal at 48 h, and continued to increase at 72 h ; While the intestinal mucosa Ca2 + -ATPase activity and STC1 mRNA level increased in 12 ~ 48h, and returned to normal level after 72h. 0.03mol / L EDTA exposure decreased the plasma calcium level in Bufo bufo gargarizans, but there was no significant change in plasma Ca2 + -ATPase activity and STC1 mRNA level compared with the control group. Conclusions The increase of plasma calcium level leads to the increase of Ca2 + -ATPase activity in the intestinal mucosa of the small intestine, which in turn enhances the expression of STC1. However, STC1 upregulation inhibits the activity of Ca2 + -ATPase in the plasma membrane by negative feedback.