不同剂量多巴胺对严重烫伤大鼠早期脏器功能的影响

Effects of different doses of dopamine on organ function of rats at early stage of severe scald

目的探讨不同剂量多巴胺对严重烫伤大鼠早期脏器功能的影响。方法将32只雄性Wistar大鼠(8~12周龄)按随机数字表法分成假伤组、单纯复苏组、小剂量组及中剂量组,每组8只。4组大鼠行心导管放置术后,将假伤组大鼠背部置于37℃温水中18s模拟致伤,其余3组大鼠背部置于97℃热水中18s造成30%体表总面积(TBSA)Ⅲ度烫伤。假伤组大鼠伤后不行其他处理,其余3组大鼠均按Parkland公式通过微量注射泵经预置的颈静脉导管补液24h。第1个24h给予4.0mL·kg^-1·%TBSA^-1生理盐水注射液,其中第1个8h给予总量的1/2,第2、3个8h共给予总量的1/2。单纯复苏组大鼠仅持续输注生理盐水,小剂量组及中剂量组大鼠在输注的生理盐水中分别加入1.25、6.00μg·kg^-1·min^-1剂量的多巴胺。分别于伤后1、3、6、12、24h,4组大鼠均经心导管采集静脉血0.5mL,分离血清。采用酶联免疫吸附测定法测定血清心肌肌钙蛋白I(cTnI)含量,采用紫外分光光度计测定血清二胺氧化酶(DAO)含量,采用胶乳增强免疫比浊法测定血清β2微球蛋白含量,采用酶比色法测定血清总胆汁酸含量,采用紫外分光光度计测定血清乳酸、丙二醛、髓过氧化物酶(MPO)含量。对数据行重复测量方差分析、单因素方差分析、LSD检验及Bonferroni校正。结果(1)伤后1、3、6、12、24h,单纯复苏组、小剂量组及中剂量组大鼠血清cTnI含量[(2.69±0.19)、(3.04±0.19)、(4.96±0.25)、(6.88±0.28)、(4.75±0.31)μg/L,(2.70±0.14)、(3.08±0.13)、(5.06±0.19)、(7.11±0.21)、(4.89±0.16)μg/L,(2.18±0.14)、(2.54±0.09)、(3.97±0.14)、(5.46±0.34)、(3.32±0.33)μg/L]均明显高于假伤组[(1.70±0.08)、(1.70±0.08)、(1.69±0.11)、(1.69±0.08)、(1.70±0.08)μg/L,P<0.05],小剂量组大鼠血清cTnI含量与单纯复苏组相近(P>0.05),中剂量组大鼠血清cTnI含量明显低于单纯复苏组及小剂量组(P<0.05)。(2)伤后1~24h,单纯复苏组、小剂量组及中剂量组大鼠血清DAO含量均明显高于假伤组(P<0.05),单纯复苏组大鼠血清DAO含量与中剂量组相近(P>0.05),小剂量组大鼠血清DAO含量明显低于单纯复苏组及中剂量组(P<0.05)。(3)伤后1~24h,单纯复苏组、小剂量组及中剂量组大鼠血清β2微球蛋白含量均明显高于假伤组(P<0.05),单纯复苏组大鼠血清β2微球蛋白含量与中剂量组相近(P>0.05),小剂量组大鼠血清β2微球蛋白含量明显低于单纯复苏组及中剂量组(P<0.05)。(4)伤后1~24h,单纯复苏组、小剂量组及中剂量组大鼠血清总胆汁酸含量相近(P>0.05)且均明显高于假伤组(P<0.05)。(5)伤后1~24h,单纯复苏组、小剂量组及中剂量组大鼠血清乳酸含量均明显高于假伤组(P<0.05),单纯复苏组大鼠血清乳酸含量与中剂量组相近(P>0.05),小剂量组大鼠血清乳酸含量明显低于单纯复苏组及中剂量组(P<0.05)。(6)伤后1~24h,单纯复苏组、小剂量组及中剂量组大鼠血清丙二醛、MPO含量均明显高于假伤组(P<0.05),单纯复苏组大鼠血清丙二醛、MPO含量与中剂量组相近(P>0.05),小剂量组大鼠血清丙二醛、MPO含量明显低于单纯复苏组及中剂量组(P<0.05)。结论在有效液体复苏下,中剂量多巴胺能改善严重烫伤大鼠早期心脏功能;而小剂量多巴胺则能缓解组织的缺血缺氧状态,减轻脏器的氧自由基损伤,改善肠道、肾脏功能。

Objective To explore the effects of different doses of dopamine on organ function of rats at early stage of severe scald. Methods Thirty-two male Wistar rats aged 8 to 12 weeks were divided into sham injury (SI) group, simple resuscitation (SR) group, small dose (SD) group, and moderate dose (MD) group according to the random number table, with 8 rats in each group. After rats in the 4 groups were performed cardiac catheterization, rats in group SI were sham injured on the back by immersing in 37 ℃ warm water for 18 s, and rats in the other 3 groups were inflicted with 30% total body surface area (TBSA) full-thickness scald on the back by immersing in 97 ℃ hot water for 18 s. Rats in group SI were not treated after the injury, while rats in the other 3 groups were performed fluid resuscitation for 24 h through jugular vein catheter with micro syringe pump according to the Parkland formula. They were given 4.0 mL·kg^-1·% TBSA^-1 normal saline during the first 24 h, of which they were given half of the total amount for the first 8 h, and they were given half of the total amount for the second and third 8 h. Rats in group SR were infused normal saline only, while rats in group SD and group MD were infused normal saline+ 1.25 μg·kg^-1·min^-1dopamine and normal saline+ 6.00 μg·kg^-1·min^-1 dopamine respectively. Volume of 0.5 mL venous blood of all rats were taken through the cardiac catheter with serum separated at post injury hour (PIH) 1, 3, 6, 12, and 24. Serum content of cardiac troponin I (cTnI) was determined by enzyme-linked immunosorbent assay;serum content of diamine oxidase (DAO) was detected by ultraviolet spectrophotometer;serum content of β2-microglobulin (β2-MG) was determined by latex-enhanced immunoturbidimetric assay;serum content of total bile acid (TBA) was determined by enzyme colorimetry;serum content of lactic acid, malondialdehyde, and myeloperoxidase (MPO) was determined by ultraviolet spectrophotometer. Data were processed with analysis of variance for repeated measurement, one-way analysis of variance, least significant difference test, and Bonferroni correction. Results (1) At PIH 1, 3, 6, 12, and 24, serum content of cTnI of rats in group SR, group SD, and group MD [(2.69±0.19),(3.04±0.19),(4.96±0.25),(6.88±0.28),(4.75±0.31)μg/L,(2.70±0.14),(3.08±0.13),(5.06±0.19),(7.11±0.21),(4.89±0.16)μg/L,(2.18±0.14),(2.54±0.09),(3.97±0.14),(5.46±0.34),(3.32±0.33)μg/L] were higher than that in group SI [(1.70±0.08),(1.70±0.08),(1.69±0.11),(1.69±0.08),(1.70±0.08)μg/L, P<0.05], serum content of cTnI of rats in group SR and group SD was similar (P>0.05), and serum content of cTnI of rats in group MD was lower than that in group SR and group SD (P<0.05).(2) At PIH 1 to 24, serum content of DAO of rats in group SR, group SD, and group MD was higher than that in group SI (P<0.05), serum content of DAO of rats in group SR and group MD was similar (P>0.05), and serum content of DAO of rats in group SD was lower than that in group SR and group MD (P<0.05).(3) At PIH 1 to 24, serum content of β2-MG of rats in group SR, group SD, and group MD was higher than that in group SI (P<0.05), serum content of β2-MG of rats in group SR and group MD was similar (P>0.05), and serum content of β2-MG of rats in group SD was lower than that in group SR and group MD (P<0.05).(4) At PIH 1 to 24, serum content of TBA of rats in group SR, group SD, and group MD was similar (P>0.05) and higher than that in group SI (P<0.05).(5) At PIH 1 to 24, serum content of lactic acid of rats in group SR, group SD, and group MD was higher than that in group SI (P<0.05), serum content of lactic acid of rats in group SR and group MD was similar (P>0.05), and serum content of lactic acid of rats in group SD was lower than that in group SR and group MD (P<0.05).(6) At PIH 1 to 24, serum content of malondialdehyde and MPO of rats in group SR, group SD, and group MD was higher than that in group SI (P<0.05), serum content of malondialdehyde and MPO of rats in group SR and group MD was similar (P>0.05), and serum content of malondialdehyde and MPO of rats in group SD was significantly lower than that in group SR and group MD (P<0.05). Conclusions With effective liquid recovery, dopamine of MD can improve early cardiac function of rats with severe scald, while dopamine of SD can alleviate tissue ischemia and hypoxia, reduce oxygen free radical damage in internal organs, and improve functions of intestine and kidney.