敲减OGT对肝细胞脂肪合成的作用研究

目的探讨敲减N-乙酰氨基葡萄糖转移酶(OGT)对肝细胞脂肪合成的影响。方法建立L02正常肝细胞脂肪变模型,蛋白免疫印迹法(Western blot)检测OGT及O-连接糖基化(O-GlcNAc)表达。建立L02细胞OGT敲减细胞系,油酸诱导后检测其脂质形成能力。实时荧光定量PCR(qRT-PCR)和Western blot检测脂肪合成相关酶的mRNA和蛋白表达。采用独立样本t检验。结果Western blot显示L02细胞脂肪变后OGT及O-GlcNAc表达均升高(P<0.05)。shOGT慢病毒感染L02细胞后,OGT mRNA相对表达水平明显下调(P<0.01)。油红O染色显示,L02 shOGT细胞内脂质减少,qRT-PCR显示系列脂肪合成酶:乙酰辅酶A羟化酶、脂肪酸合成酶和硬脂酰辅酶A去饱和酶mRNA相对表达水平均降低,差异具统计学意义(P值均<0.05),蛋白水平与mRNA相对表达量一致。结论敲减OGT后可通过降低O-GlcNAc水平抑制肝细胞脂肪合成。     

Mono-2-ethylhexyl phthalate induces the expression of genes involved in fatty acid synthesis in HepG2 cells

Mono-2-ethylhexyl phthalate (MEHP) is a major bioactive metabolite in the widely used industrial plasticizer diethylhexyl phthalate (DEHP) that has been found to be toxic to the liver. The aim of this study is to determine whether MEHP exposure can change the expression of fatty acid metabolism-related genes in HepG2 cells, which might be related to non-alcoholic fatty liver disease (NAFLD). The results revealed that exposure to MEHP promoted lipid accumulation in HepG2 cells. The levels of intracellular triglycerides in the hepatocytes increased after exposure to 0.8–100 μM MEHP for 24 h and 48 h. The genetic expressions of SREBP-1c, ChREBP, ACC1, FASN, and SCD significantly increased at 6 h after exposure to MEHP. At 24 h, the expression of the SREBP-1c and ChREBP genes remained increased, while the expression of the FASN and SCD genes decreased. At 48 h, the expression of SREBP-1c, ChREBP, ACC1, FASN, and SCD decreased. Furthermore, the levels of proteins including ACC1, FASN, SCD, and ChREBP (except SREBP-1c) increased at 24 h. These findings suggest that MEHP exposure can promote fatty acid synthesis in hepatocytes by regulating the expression of relevant genes and proteins, contributing to NAFLD.     

轴状脂肪移植的实验和初步临床研究

目的通过与Coleman方法比较,探讨轴状脂肪移植方法的可行性。方法采用Coleman方法及轴状脂肪移植方法,分别于11例拟行头面部脂肪移植患者的下腹部抽取脂肪。取3～4周龄免疫缺陷裸鼠48只,雌雄不限,体重8.6～12.2 g;随机分为两组,每组24只。以背部皮下间隙为移植受区,实验组移植0.5 mL轴状脂肪移植方法获得的人体脂肪组织,对照组移植0.5 mL Coleman方法获得的人体脂肪组织。术后大体观察实验动物背部外观,于1、2、4、8周两组随机处死6只裸鼠,取出背部皮下移植脂肪进行大体、组织学及免疫组织化学染色观察,并于取出脂肪前后对裸鼠称重,计算移植脂肪重量。脂肪抽取术后即刻取脂肪组织进行葡萄糖转移实验和脂肪细胞活性测定。2010年5月-2011年10月,临床应用面部轴状脂肪移植治疗11例局部凹陷性畸形。结果术后实验组裸鼠背部隆起样外观基本维持,对照组2周时已趋于平坦。两组植入脂肪重量相似(P>0.05);除术后2周外,其余各时间点实验组残余脂肪重量均显著高于对照组(P<0.05)。组织学观察示实验组细胞形态保持良好,血管分布均匀;对照组细胞破坏再吸收显著,血管集中分布于移植组织边缘。术后实验组完整脂肪细胞计数均明显多于对照组,除术后2周外其余各时间点组间比较差异均有统计学意义(P<0.05)。实验组毛细血管计数均少于对照组,术后1、2周比较差异有统计学意义(P<0.05),但4、8周时差异无统计学意义(P>0.05)。轴状脂肪移植方法抽取的脂肪组织葡萄糖转移量为(1.462±0.080)mmol/L,显著高于Coleman方法抽取的脂肪组织(1.153±0.199)mmol/L(t=3.317,Ρ=0.021);且轴状脂肪移植方法抽取的脂肪组织细胞活性更佳。临床应用患者均获随访,随访时间2～9个月;随访期间受区未见明显萎缩及塌陷。结论与Coleman方法比较,轴状脂肪移植方法获得的脂肪组织可保持原结构和良好活性,移植术后能更早与受区建立血液循环,术后组织再吸收率低,形态维持时间长。     

脂肪乳剂建立大鼠高脂血症模型的研究

目的 用两种不同浓度脂肪乳剂按灌胃法建立大鼠高脂血症模型,并对其血脂水平进行评价,为建立合适的高脂血症动物模型提供依据.方法 将30只150～180 g健康雄性SD大鼠随机分为正常对照组、低浓度脂肪乳剂组及高浓度脂肪乳剂组,每组10只.分别饲以基础饲料、低浓度配方脂肪乳剂(20％猪油、6％胆固醇、0.2％丙基硫氧嘧啶、2％胆酸钠及10％吐温-80)及高浓度配方脂肪乳剂(30％猪油、10％胆固醇、1％丙基硫氧嘧啶、5％胆酸钠及20％吐温-80).2周后处死大鼠,测定血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)及低密度脂蛋白胆固醇(LDL-C)水平.结果 高浓度脂肪乳剂组血清TC、TG、HDL-C及LDL-C水平与正常对照组及低浓度脂肪乳剂组比较均升高(P＜0.05),低浓度脂肪乳剂组血清TC、TG及HDL-C水平与正常对照组比较差异无统计学意义(P＞0.05).结论 高浓度脂肪乳剂可以成功建立SD大鼠高脂血症模型,低浓度脂肪乳剂不适合用于建立SD大鼠高脂血症模型.     

一期矫正上睑下垂合并上睑凹陷畸形

目的 探讨一期矫正上睑下垂合并上睑凹陷的手术方式及疗效.方法 术中根据上睑提肌肌力及上睑提肌腱膜的形态情况,选择上睑提肌腱膜修补术、腱膜折叠、缩短术或联合术式,以调整上睑提肌的肌力及其腱膜与睑板连接状况;同时将眶脂肪移位到凹陷区,或者采集适量自体颗粒脂肪注入至凹陷区的眶脂肪包膜内,复位眶隔膜;最后以常规切开重睑成形术法缝合切口.结果 本组15例(30只眼),11例获6～ 40个月随访,平均9.5个月,上睑下垂矫正满意,未见睑下垂复发,上睑凹陷消失,无并发症,眼部外观及功能恢复正常.结论 对上睑下垂合并上睑凹陷的患者,施行自体颗粒脂肪眶脂肪包膜内移植和眶脂肪移位法矫治上睑凹陷,并同期行上睑下垂矫正一期整形,在恢复上睑的解剖结构、正常眼位、运动功能、美化眼外形、趋于年轻化等方面均取得良好的手术效果.     

早期防治严重创伤行骨科手术并发脂肪栓塞综合征40例临床观察

目的探讨早期防治严重创伤行骨科手术并发脂肪栓塞综合征的临床特点和治疗方法。方法选取2008年7月—2012年3月因严重创伤行骨科手术并发脂肪栓塞患者40例,随机分为A组17例、B组23例。两组在综合治疗治疗基础上,分别给予0.1、0.2 g甲泼尼龙静脉注射,比较两组治疗前后血氧浓度、PaO2、血红蛋白、血小板和心率。结果血氧浓度、PaO2、血红蛋白、血小板和心率治疗后A组分别为(91.57±3.37)mm Hg(1 mm Hg=0.133 kPa)、(90.17±2.01)%、(116.82±3.96)g/L、(107.62±5.13)×109/L、(88.94±8.48)次/min,B组分别为(99.31±3.72)mm Hg、(94.24±1.59)%、(124.09±3.14)g/L、(112.37±3.96)×109/L、(95.26±8.26)次/min,比治疗前均有明显好转,差异均有统计学意义(均P<0.05),但是两组患者之间比较差异均无统计学意义(均P>0.05)。结论严重创伤行骨科手术并发脂肪栓塞综合征临床表现复杂,应进行积极预防和治疗,减少不良后果发生。     

Long chain versus medium chain lipids in patients with ARDS: effects on pulmonary haemodynamics and gas exchange

Objective: To compare pulmonary haemodynamic and gas exchange alterations in septic patients with ARDS receiving long-chain triglycerides (LCT) versus medium-chain triglycerides (MCT). Design: Prospective, randomised, clinical study. Setting: Surgical ICU patients in a University Hospital. Patients: Twenty-one septic patients with ARDS were randomly assigned to receive 50 % of their non-protein caloric requirements as either 20 % LCT (group 1, n = 10) or 20 % 1 : 1 mixture of LCT/MCT (group 2, n = 11). Intervention: Intravenous infusion of LCT and LCT/MCT combinations at a rate of 12 g · h^{− 1}. Measurements and results: The LCT infusion was associated with an increase of pulmonary venous admixture (Qva/Qt) from 24 % ± 5 % to 37 % ± 6 %, an increase of mean pulmonary artery pressure (MPAP) from 25 ± 5 to 33 ± 4 mmHg and decrease of PaO₂/FIO₂ from 240 ± 30 to 180 ± 35. LCT/MCT administration was only associated with an elevation of oxygen consumption (VO₂) from 329 ± 14 to 396 ± 12 ml/min. During lipid infusion group 1 patients presented higher Qva/Qt (37 % ± 6 % vs 25 % ± 4 %), MPAP (33 ± 4 vs 27 ± 3 mmHg) and VO₂ (359 ± 11 vs 396 ± 12 ml/min) and lower PaO₂/FIO₂ (180 ± 35 vs 235 ± 30) values compared to group 2. Conclusion: In conclusion, we have shown that, in septic patients with respiratory failure, LCT administration was associated with more significant changes of Qva/Qt, MPAP and PaO₂/FIO₂ compared to infusion of an LCT/MCT 1 : 1 emulsion. Clinically, these transient alterations might cause serious problems in patients with marginal arterial oxygenation and cardio-respiratory impairment. Received: 23 July 1997 Accepted: 15 May 1998