Long-Term Animal Feeding Trial of the Refined Konjac Meal Ⅰ. Effects of the Refined Konjac Meal on the Calcium and Phosphorus Metabolism and the Bone in Rat

Effects of refined konjac meal (RKM) on the calcium and phosphorus metabolism and bone parameters were observed in rats of both sexes fed with food containing 1% of RKM for 18 months. A comparable group of rats fed on basic diet only was used as a control.Results obtained indicate that all the measured parameters (serum calcium and phosphorus level, femur weight and its calcium and phesphorus content, and the osteometry of the tibia) showed no significant difference between the experimental and the control groups.Thus there is no adverse effect either on the calcium and phosphorus metabolism or on the bone after a long-term intake at a moderate dosage.

Effect of dietary calcium or phosphorus deficiency on bone development and related calcium or phosphorus metabolic utilization parameters of broilers from 22 to 42 days of age

This experiment was conducted to investigate the effect of dietary calcium(Ca)or phosphorus(P)deficiency on bone development and related Ca or P metabolic utilization parameters of broilers from 22 to 42 days of age based on our previous study,which indicated that dietary Ca or P deficiency impaired the bone development by regulating related Ca or P metabolic utilization parameters of broilers from 1 to 21 days of age.A total of 504 one-day-old Arbor Acres male broilers were randomly assigned to 1 of 4 treatments with 7 replicates in a completely randomized design,and fed the normal control and Ca-or P-deficient diets from 1 to 21 days of age.At 22 days of age,the broilers were further fed the normal control diet(0.90%Ca+0.35%non-phytate P(NPP)),the P-deficient diet(0.90%Ca+0.18%NPP),the Ca-deficient diet(0.30%Ca+0.35%NPP)or the Ca and P-deficient diet(0.30%Ca+0.18%NPP),respectively.The results showed that dietary Ca or P deficiency decreased(P<0.05)tibia bone mineral density(BMD),bone breaking strength(BBS),ash content,tibia ash Ca content and serum P content on days 28 and 42,but increased(P<0.05)tibia alkaline phosphatase(ALP)activity of broilers on day 42 compared with the control group.Furthermore,the broilers fed the P-deficient diet had the lowest(P<0.05)tibia BMD,BBS,ash content,serum P content and the highest(P<0.05)serum Ca content on day 28 compared with those fed the Ca-deficient or Ca and P-deficient diets.The results from the present study indicated that the bone development and related Ca or P metabolic utilization parameters of broilers were the most sensitive to dietary P deficiency,followed by dietary Ca deficiency or Ca and P-deficiency;dietary Ca or P deficiency impaired the bone development possibly by regulating serum Ca and P contents as well as tibia Ca content and ALP activity of broilers from 22 to 42 days of age.

Is the Cut off Limit of Normal Uric Acid ＆ Calcium in Tropical Countries Different？

Introduction： Nephrolithiasis is quite common in this part of the world.In the metabolic workup Uric acid and Calcium assay are important. Calcium ＆ Uric acid lithiasis accounts for significant number of cases. But, the values given as reference do not seem to apply in tropical countries like India. We tried to analyse the values of Serum Calcium ＆ Uric acid in both normal healthy individuals and those with calculus disease in out patient department. Material and methods： The study was conducted in outpatient department wherein Serum Uric acid, Calcium ＆ Phosphorus levels were assessed in fasting state in all patients irrespective of age and sex in the period Jan. 2010- June 2015. A total of 9887 patients with stone disease were kept in Group A and 8967 patients with other diseases in group B who acted as control, were enrolled for the study. The demographic profile was recorded and associated metabolic disorders were also documented. Patients with associated features of bony pains and gout were also specified. Result： The Uric acid levels in the control group B were quite lower than the reference values in either sex. However, the values were more than 6 mg/dl in nephrolithiasis group A. The S.Calcium levels of control in group B were significantly lower than the reference value and patients with nephrolithiasis in group A also had hypocalcemia. Conclusion： Nephrolithiasis is a metabolic disorder with majority of patients having higher Uric acid levels with hypocalcemia in our population.The normal values in control group is on the lower side of reference value which could be due to variation on account of climatic, dietary and geographical factors. It needs broader studies to redefine reference values of Uric acid and Calcium in tropical countries like India.

Metabolic bone disease in the preterm infant: Current state and future directions

Neonatal osteopenia is an important area of interest for neonatologists due to continuing increased survival of preterm infants. It can occur in high-risk infants such as preterm infants, infants on long-term diuretics or corticosteroids, and those with neuromuscular disorders. Complications such as rickets, pathological fractures, impaired respiratory function and poor growth in childhood can develop and may be the first clinical evidence of the condition. It is important for neonatologists managing such high-risk patients to regularly monitor biochemical markers for evidence of abnormal bone turnover and inadequate mineral intake in order to detect the early phases of impaired bone mineralization. Dual-energy X-ray absorptiometry has become an increasingly used research tool for assessing bone mineral density in children and neonates, but more studies are still needed before it can be used as a useful clinical tool. Prevention and early detection of osteopenia are key to the successful management of this condition and oral phosphate supplements should be started as soon as is feasible.

Mechanisms of Myocardial Stunning in Stress-Induced Cardiomyopathy

Stress-induced cardiomyopathy,in contrast to acute myocardial infarction,is a type of acute heart failure characterized by reversible left ventricular dysfunction.Cardiac imaging primarily reveals left ventricle myocardial stunning,81.7%of which is apical type.Emotional or psychological stress usually precedes the onset of stress-induced cardiomyopathy,which is increasingly being recognized as a unique neurogenic myocardial stunning disease.To distinguish between acute myocardial infarction and acute viral or auto-immune myocarditis,this review summarizes specific mechanisms of myocardial stunning in stress-induced cardiomyopathy,such as calcium disorders,metabolic alterations,anatomical and histological variations in different parts of the left ventricle,and microvascular dysfunction.

Research Progresses on Physiological Functions of Vitamin D

Vitamin D is a fat soluble vitamin that is foundin a variety of forms , amongwhich 1,25-（0H） 2D3 is themain active form. It not only exhibits a major physiological function to regulate the metabolism of calcium and phosphorus, but also relates to the prevention and treatment of a variety of diseases such as lung diseases, cancers, diabetes, tuberculosis, lupus erythematosus, autoimmune diseases and liver damage. In this paper, the latest research progresses of the physiological function of vitamin D were summarized and discussed, aiming at providing the solid basis for utilization and application of vitamin D.

六味地黄丸干预FGF23/Klotho轴对慢性肾衰竭钙磷代谢紊乱模型大鼠的影响

目的:观察六味地黄丸通过成纤维细胞生长因子23(FGF23)/Klotho轴对慢性肾衰竭钙磷代谢紊乱模型大鼠的影响及其干预机制。方法:50只SPF级SD大鼠随机分为假手术组(10只)、手术组(40只),手术组采用5/6肾切除及高磷饮食喂养构建慢性肾衰竭钙磷代谢紊乱大鼠模型,模型复制成功后将30只造模成功大鼠随机分为模型组、骨化三醇组、六味地黄丸组,每组10只。六味地黄丸组、骨化三醇组大鼠分别予六味地黄丸和骨化三醇灌胃,假手术组及模型组大鼠予等体积的蒸馏水灌胃,持续给药8周。HE染色观察肾组织变化,检测大鼠血清钙(Ca^(2+))、磷(P^(3+))、碱性磷酸酶(ALP)、甲状旁腺激素(PTH)、肌酐(Scr)、尿素氮(BUN),免疫组化及Western blotting法检测大鼠肾皮质Klotho、FGF23蛋白的表达。结果:HE染色显示,模型组大鼠肾小球结构紊乱、肾小管扩张,间质有大量炎症细胞浸润;与模型组比较,六味地黄丸组大鼠肾小球轻度增生,肾小管轻度扩张,间质炎症细胞浸润数目减少。模型组大鼠血清Scr、BUN、P^(3+)、PTH、ALP高于假手术组(P<0.01),体质量、血清Ca^(2+)低于假手术组(P<0.01);六味地黄丸组大鼠血清Scr、BUN、P^(3+)、PTH、ALP低于模型组,体质量、血清Ca^(2+)高于模型组(P<0.01)。模型组大鼠肾皮质Klotho蛋白相对表达量低于假手术组(P<0.05),FGF23蛋白相对表达量高于假手术组(P<0.01);六味地黄丸组大鼠肾皮质Klotho蛋白相对表达量高于模型组(P<0.01),FGF23蛋白相对表达量低于模型组(P<0.01)。六味地黄丸组大鼠血Scr、BUN及肾皮质FGF23、Klotho蛋白相对表达量与骨化三醇组比较,差异无统计学意义(P>0.05)。六味地黄丸组大鼠血P^(3+)、Ca^(2+)高于骨化三醇组(P<0.05)。结论:六味地黄丸可能通过调控FGF23/Klotho轴改善慢性肾衰竭钙磷代谢紊乱模型大鼠的肾功能和钙磷代谢。

复方氨基酸胶囊治疗维持性血液透析患者营养不良及钙磷代谢障碍的有效性和安全性

目的·探索复方氨基酸胶囊治疗维持性血液透析患者营养不良及钙磷代谢障碍的有效性和安全性。方法·采用前瞻性、随机、对照、单中心的研究设计,40例上海交通大学医学院附属仁济医院的维持性血液透析患者随机分入治疗组(n=21)和对照组(n=19),治疗组在维持性血液透析常规治疗的基础上予口服复方氨基酸胶囊,对照组无特殊营养干预,每3月检测1次2组患者的血清白蛋白、前白蛋白、血红蛋白、铁蛋白,血钙、血磷、1, 25-二羟维生素D3[1, 25-(OH)_(2)-D_(3)]和全段甲状旁腺激素水平,并记录死亡、心脑血管意外、血管通路失功等不良事件的发生情况,共随访9个月。结果·治疗组血清白蛋白和前白蛋白水平在第6月和第9月时较基线升高(白蛋白t=3.574、5.599,均P<0.05;前白蛋白t/Z=-2.485、2.921,均P<0.05),对照组白蛋白在第9月开始升高,但增幅显著小于治疗组(t=3.877,P=0.001),前白蛋白水平则无明显变化。治疗组血红蛋白和铁蛋白水平在第3月即出现升高(血红蛋白t=2.192,铁蛋白t=2.994,均P<0.05)。治疗组血磷在第3月和第9月时较基线明显降低(t/Z=-2.743、-2.103,均P<0.05),而对照组血磷在第3月和第6月时无明显变化,第9月时较基线升高(Z=-2.178,P=0.029)。治疗组血钙和1, 25-(OH)_(2)-D_(3)水平在第3月和第6月均较基线升高(血钙t=4.581、4.922,均P=0.000;1, 25-(OH)_(2)-D_(3)t/Z=4.504、-2.374,均P<0.05),对照组血钙增幅显著小于同时期治疗组,1, 25-(OH)_(2)-D_(3)水平则无明显变化。2组患者的血全段甲状旁腺素水平、不良事件发生率及其他实验室指标在随访期内无统计学差异。结论·复方氨基酸胶囊在改善维持性血液透析患者营养状况、调节钙磷代谢方面有一定的疗效,且安全性高。

Latest assessment methods for mitochondrial homeostasis in cognitive diseases

Mitochondria play an essential role in neural function,such as supporting normal energy metabolism,regulating reactive oxygen species,buffering physiological calcium loads,and maintaining the balance of morphology,subcellular distribution,and overall health through mitochondrial dynamics.Given the recent technological advances in the assessment of mitochondrial structure and functions,mitochondrial dysfunction has been regarded as the early and key pathophysiological mechanism of cognitive disorders such as Alzheimer’s disease,Parkinson’s disease,Huntington’s disease,mild cognitive impairment,and postoperative cognitive dysfunction.This review will focus on the recent advances in mitochondrial medicine and research methodology in the field of cognitive sciences,from the perspectives of energy metabolism,oxidative stress,calcium homeostasis,and mitochondrial dynamics(including fission-fusion,transport,and mitophagy).

反复静脉钙刺激对慢性肾衰竭大鼠血管钙化的影响

目的探讨反复静脉钙刺激对腺嘌呤饮食诱导的慢性肾脏病(chronic kidney disease,CKD)大鼠主动脉钙化的影响。方法选择SD大鼠32只,采用数字表法随机分为对照组和模型组,基线时检测血清肌酐、尿素氮、钙、磷水平,分别给予正常饮食或0.75%腺嘌呤饮食喂养,6周后全部更换为普通饲料。对照组和模型组大鼠再分别随机分为两组,共四组:对照+氯化钙组(Cont+CaCl_(2))、对照+0.9%(质量分数)氯化钠注射液(以下简称生理盐水)组(Cont+NaCl)、模型+氯化钙组(CKD+CaCl_(2))、模型+生理盐水组(CKD+NaCl),每组8只。分别采用隔日尾静脉注射氯化钙溶液(100 mg/kg)或等量生理盐水共8周,随后将大鼠处死,取血清检测肌酐、尿素氮、钙、磷水平;留取主动脉测定血管钙含量并进行Von Kossa染色观察有无钙化发生,采用免疫组织化学染色法观察成骨转分化指标成骨细胞特异性和转录因子(runt-related transcription factor 2,Runx2)的分布和表达情况,采用Western blotting法检测成骨转分化指标骨形态蛋白2(bone morphogenetic protein 2,BMP-2)的蛋白表达。结果基线时各组大鼠体质量及生化指标差异无统计学意义(P>0.05);第14周结束时与对照组相比,模型组大鼠血清肌酐、尿素氮水平升高,血钙降低、血磷升高,差异有统计学意义(P<0.05);与CKD+NaCl组比较,CKD+CaCl_(2)组血清钙、磷水平及主动脉钙含量差异无统计学意义(P>0.05),两组大鼠主动脉Von Kossa染色均为阴性;与对照组相比,模型组主动脉Runx2和BMP-2表达增加;与CKD+NaCl组比较,CKD+CaCl_(2)组主动脉Runx2和BMP-2表达差异无统计学意义。结论在本实验条件下,反复静脉钙刺激对腺嘌呤饮食诱导的CKD大鼠无诱发主动脉钙化作用,对主动脉成骨转分化情况无明显影响。

围产期母畜低血钙症的钙代谢机制及对相关代谢疾病的影响

围产期母畜由于体内蛋白质、矿物质和能量代谢的急剧变化,容易导致钙的流失和平衡失调,进而引发母畜围产期低血钙症。临床和亚临床低血钙症不仅能够影响母畜的生产性能,还会影响围产期机体的营养代谢,进一步诱发母畜在围产期出现其他生理变化和疾病,如酮病、皱胃移位、难产、乳腺炎及子宫疾病等。因此,全面深入地研究围产期母畜低血钙症的钙代谢机制及其对相关代谢疾病的影响,对于保障围产期母畜的健康和提高生产性能具有重要意义。文章详述了围产期母畜低血钙症的病因和现状、钙代谢机制、综合防治措施以及与其他疾病之间的关联,为降低围产期母畜低血钙症发病率以及改善饲养管理提供参考。

气体信号分子硫化氢防治骨质疏松的作用与机制

作为一种气体信号分子,近年来硫化氢(H_(2)S)防治骨质疏松的作用得到证实,其病理生理机制也陆续被阐明。H_(2)S能通过拮抗氧化应激和炎症反应、促进血管生成、调节肠道菌群和钙磷代谢,促进骨形成、抑制骨吸收,进而防治多种类型的骨质疏松,如绝经后骨质疏松、糖皮质激素或高同型半胱氨酸引发的骨质疏松。本文对现有研究进行总结,为进一步探索骨质疏松症的发病机制和治疗方案提供新思路。

Transcriptome reveals overview of Ca^(2+) dose-dependent metabolism disorders in zebrafish larvae after Cd^(2+) exposure

Cadmium (Cd),a ubiquitous environmental hazardous heavy metal,poses a significant threat to the health of aquatic organisms,including teleosts.Although the toxic profile of Cd is well recognized,little is known regarding the overall view of toxic responses to varying aquatic environmental parameters (e.g.,water hardness) at an individual level.Herein,differences in water hardness were partially mimicked by adjusting Ca^(2+)levels in E3 medium.As an in vivo model,zebrafish embryos were exposed to variable Ca^(2+)levels (NV,normal Ca^(2+);LV,low Ca^(2+);HV,high Ca^(2+)) alone or combined with 30.7μg/L Cd^(2+)(NC,LC,and HC,respectively) until 144 hr post-fertilization.The genome-wide transcriptome revealed differentially expressed genes between groups.Functional enrichment analysis found that biological processes related to metabolism,particularly lipid metabolism,were significantly disrupted in NC and LC treatments,while a remission was observed in the HC group.Biochemical assays confirmed that the decrease in Ca^(2+)enhanced synthesis,inhibited mobilization and increased the storage of lipids in Cd^(2+)treatments.This study suggests that the toxic effect of Cd on biological pathways will be influenced by Ca^(2+),which will improve the toxicological understanding and facilitate accurate assessment of Cd.

血清PTH、ALP指标与维持性血液透析患者钙磷代谢紊乱的关系

目的:探讨维持性血液透析(MHD)患者钙磷代谢紊乱的发生情况,并分析其发生与血清甲状旁腺激素(PTH)、碱性磷酸酶(ALP)的关系。方法:选择上饶市中医院2022年7月—2023年9月收治的80例MHD患者,统计患者入院时一般资料,检测血清PTH、ALP水平,并依据MHD 3个月时钙磷代谢紊乱发生情况分为钙磷代谢紊乱组和钙磷代谢正常组,分析血清PTH、ALP水平与MHD患者钙磷代谢紊乱的关系。结果:80例MHD患者透析3个月时出现钙磷代谢紊乱33例,发生率为41.25%;两组年龄、性别、原发疾病、病程、体重指数、收缩压、舒张压、吸烟史、饮酒史及血磷、血钙、尿酸、血红蛋白、总胆固醇、甘油三酯、空腹血糖水平比较,差异均无统计学意义(P>0.05);钙磷代谢紊乱组肌酐、血清PTH、ALP、超敏C反应蛋白水平均高于钙磷代谢正常组,差异均有统计学意义(P<0.05);经logistic回归分析结果显示,肌酐、PTH、ALP、超敏C反应蛋白是MHD患者钙磷代谢紊乱发生的危险因素(OR>1,P<0.05);绘制受试者操作特征(ROC)曲线,结果显示,血清PTH、ALP水平单独及联合预测MHD患者钙磷代谢紊乱的AUC分别为0.853、0.837、0.925,具有一定预测价值。结论:血清PTH、ALP水平与MHD患者发生钙磷代谢紊乱密切相关,且对预测钙磷代谢紊乱的发生具有一定预测价值。

天然产物抗心肌缺血/再灌注损伤分子机制的研究进展

心肌缺血/再灌注损伤(myocardial ischemia/reperfusion injury,MIRI)机制主要涉及氧化应激、炎症反应、钙超载、细胞凋亡、自噬和能量代谢障碍等。天然产物因具有低毒性、多靶点等优势,已被广泛应用于心脑血管疾病的防治,为了深入研究它们对MIRI的治疗机制,本文综合评述了天然产物在抗MIRI相关信号通路方面的研究进展,并利用网络药理学分析技术预测天然产物治疗MIRI的机制。由于天然产物机制复杂,完全阐明其抗MIRI分子机制仍任重道远。

血液透析联合血液灌流在维持性血液透析患者钙磷代谢紊乱治疗中的应用

目的:探讨血液透析联合血液灌流在维持性血液透析患者钙磷代谢紊乱治疗中的应用效果。方法:选择本院2013年6月至2013年12月接受维持性透析治疗的尿毒症患者80例,按照随机数字法分为两组,各40例。治疗组为血液灌流联合血液透析组,对两组患者治疗前、后临床指标的变化,以及患者临床症状改善情况。结果:治疗后治疗组的血磷、钙磷乘积、i PTH、BUN、Scr和β2-MG均显著下降,血钙含量显著升高,且治疗后4个月及6个月在血磷、血钙、钙磷乘积、i PTH和β2-MG含量方面与对照组存在统计学差异(P<0.05)。治疗6个月后治疗组P1NP、β-CTX和BGP含量均显著下降,且均与对照组存在统计学差异(P<0.05)。结论:血液透析与血液灌流联合使用具有可有效降低MHD患者体内血清全段甲状旁腺素含量,纠正钙磷代谢紊乱。

维持性血液透析患者血清钙、磷及甲状旁腺激素水平的横断面调查

目的调查我院维持性血液透析(血透)患者中钙磷代谢紊乱及继发性甲状旁腺功能亢进症的发生情况。方法以182例血透患者作为调查对象,所有患者透析龄>3个月。采用放射免疫法检测患者透前全段甲状旁腺激素(iPTH)水平。对iPTH与血钙、血磷、血清白蛋白浓度、透析龄及透析频率等指标的相关性进行多元逐步回归分析。结果 182例调查对象血清钙浓度达标91例(50.0%),血磷浓度达标49例(26.9%),钙磷乘积达标70例(38.5%),iPTH浓度达标41例(22.5%),仅有29例(15.9%)的患者所有指标均达到控制目标值。多元逐步回归分析显示,iPTH与残余尿量和透析龄相关。结论维持性血透患者钙磷代谢紊乱及继发性甲状旁腺功能亢进治疗达标率仍较低。

维持性血液透析患者钙磷代谢紊乱的异常因素分析

目的探讨维持性血液透析患者钙磷代谢紊乱的异常因素。方法对130例维持性血液透析患者的钙、磷浓度、钙磷浓度乘积及甲状旁腺激素(i PTH)进行测定,并与K/DOQI2003指南及KDIGO2009指南指标进行比较。结果 130例患者的血钙、血磷、钙磷乘积和i PTH以K/DOQI2003指南为标准,达标率分别为48.12%,48.23%,78.75%,20.28%;以KDIGO2009指南为标准,达标率分别为47.71%,28.74%,38.30%。血流量≥300 m L/min患者血磷水平较血流量<300 m L/min患者明显降低(t=2.892,P<0.05)。透析时间≥3年患者血钙、钙磷乘积和i PTH水平较透析时间<3年患者明显增高(t=2.479、5.681、3.012,P<0.05)。年龄≥50岁患者血磷、钙磷乘积水平较年龄<50岁患者明显降低(t=2.212、3.367,P<0.05)。结论维持性血液透析患者存在钙磷代谢异常,控制水平仍然达不到指南要求。随着时间延长,钙磷代谢紊乱问题有所加重。

维生素E联合血液灌流在维持性血液透析患者中的临床应用价值

目的探讨维生素E联合血液灌流对维持性血液透析（MHD）患者氧化应激、微炎症和钙磷代谢紊乱状态的影响。方法本院2014年1~6月接受维持性透析治疗的患者60例,按照随机数字法分为两组,各30例。对照组采用血液透析治疗,试验组在此基础上采用维生素E联合血液灌流进行治疗。观察两组治疗前、治疗6个月时白细胞介素6（IL-6）、白细胞介素8（IL-8）、C-反应蛋白（CRP）、肿瘤坏死因子α（TNF-α）、丙二醛（MDA）、超氧化物歧化酶（SOD）、终末氧化蛋白产物（AOPP）、谷胱甘肽过氧化物酶（GSH-PX）以及血钙、血磷、1,25-（OH）2D3水平。结果治疗前两组相关指标比较差异均无统计学意义（P〉0.05）,治疗后6个月试验组血清IL-6、IL-8、CRP、TNF-α、MDA、AOPP和血磷水平低于治疗前,差异均有统计学意义（P〈0.01）,SOD、GSH-PX、血钙和1,25（OH）2D3高于治疗前,差异均有统计学意义（P〈0.01）,治疗后两组上述指标差异均有统计学意义（P〈0.05）。两组治疗期间均未发生过敏反应,出血,感染等严重的不良反应。结论维生素E联合血液灌流可以有效地改善维持性血液透析患者的微炎症状态和氧化应激状态,维持其钙磷代谢平衡,值得临床推广应用。

热应激大鼠心肌线粒体功能的变化

目的：观察不同强度热应激大鼠心肌线粒体氧化磷酸化功能和钙储存功能的变化。方法：用Ｋｌａｒｋ氧电极极谱方法测定线粒体氧化代谢功能，用生物发光法测定心室肌ＡＴＰ含量及线粒体Ｃａ２＋－ＡＴＰ酶活性，用电感藕合等离子体－原子放射光谱仪测定心肌线粒体内钙含量。结果：热应激大鼠心肌线粒体呼吸控制率（ｒｅｓｐｉｒａｔｏｒｙｃｏｎｔｒｏｌｒａｔｉｏ，ＲＣＲ）及氧化磷酸化效率（Ｐ／Ｏ）均随动物直肠温度的升高逐步显著降低，当大鼠直肠温度超过４２℃时，ＲＣＲ与Ｐ／Ｏ分别较对照下降３１４％，１１０５％。直肠温度４２℃以上，大鼠的心室肌ＡＴＰ含量仅为对照的３７５％。热应激大鼠心肌线粒体Ｃａ２＋－ＡＴＰ酶活性和钙含量亦明显降低，直肠温度４２℃以上大鼠的该两项指标可较对照值降低达３２６％和３１３％，显示了线粒体钙代谢的异常变化。结论：热应激机体心肌线粒体的氧化代谢和钙功能受损是热应激时心功能紊乱的重要原因。