严重烧伤对小鼠生长发育及生长激素水平的影响

Effect of severe burn on growth and development and the level of growth hormone in mice

目的分析小鼠严重烧伤后体格发育、学习记忆能力和运动能力的改变，以及体内生长激素（GH）水平的变化趋势、、方法取104只3～4周龄的健康清洁级BALB／c小鼠，采用随机数字表法分为正常对照组（不作任何处理）、7s烧伤组（背部造成20％TBSA深Ⅱ度烧伤）、10s烧伤组（背部造成20％TBSAIII度烧伤）、阴性对照组（模拟烧伤组处理过程但不致伤），每组26只。伤前测量各组8只小鼠体质量、体长、尾长、伤后l、3、7d2个烧伤组分别选取6只小鼠采血并处死，采用ELISA试剂盒测定m清巾GH水平。将2个烧伤组剩余的8只小鼠饲养至成年，伤后62d再次测量小鼠的体质量、体k、尾长．计算其增长百分比；伤后66、67、68d检测小鼠逃避潜伏期，伤后69d检测小鼠跨越原平行位置次数、目标象限停留时间百分比，以测试小鼠学习记忆能力；伤后70d检测小鼠负蕊游泳时间和爬杆时间，测试小鼠运动能力。2个对照组小鼠于相同时相点进行上述检测。，对数据行单因素方差分析，两两比较行独立样本t检验；方差不齐则行Welch检验。结果（1）7s烧伤组小鼠伤后1d血清中GH水平为（3021±506）pg／mL，明显低于正常对照组[（3728±412）pg／mL，t=2．656，P〈0．05]；伤后3、7d血清中GH水平分别为（3098±503）、（3199±275）pg／mL，与正常对照组[（3872±785）、（3301±600）pg／mL]接近（t值分别为2．033、0．379，P值均大于0．05）。10s烧伤组小鼠伤后1、3、7d血清中GH水平分别为（28594-447）、（2707±151）、（2666±222）pg／mL，均明显低于正常对照组（￡值分别为3．504、3．57l、2．429，P〈0．05或P〈0．01）．、（2）7s烧伤组和10s烧伤组小鼠的体质量增长百分比分别为（112±57）％、（106±36）％，体长增长百分比分别为（32±12）％、（30±8）％，尾长增长百分比分别为（40±15）％、（32±7）％；正常对照组小鼠的体质量、体长、尾长增长百分比分别为（155±22）％、（46±6）％、（63±10）％。除7s烧伤组体质量增长百分比与正常对照组接近外（t=1．997，P〉0．05）．2个烧伤组小鼠各项指标增长百分比均明显低于于正常对照组（￡值为3．092～6．910，P值均小于0．01）。（3）10s烧伤组小鼠伤后67、68d逃避潜伏期分别为（33±12）、（33±11）s，明混长于正常对照组[（20±8）、（20±7）s，t值分别为2．421、2．692，P值均小于0．05]；伤后69d跨越原平台位置次数[（1．6±1．8）次]与正常对照组[（3．2±1．5）次]接近（t=1．989，P〉0．05）；伤后69d目标象限停留时间百分比[（28±7）％]明湿低于正常对照组[（48±16）％，t=3．076，P〈0．01]。7s烧伤组小鼠伤后67d逃避潜伏期为（30±7）s，较正常对照组明硅延长（t=2．659，P〈0．05）；伤后69d跨越原平台位置次数[（2．0±1．1）次]和目标象限停留时间百分比[（36±11）％]与正常对照组接近（t值分别为1．930、1．670，P值均大于0．05）。（4）伤后70d，10S烧伤组小鼠的爬杆时间、负重游泳时间分别为（30±11）s、（38±39）rain，较正常对照组[（47±11）s、（122±74）rain]明最缩短（t值分别为3．108、2．868，P〈0．05或P〈0．01）。7S烧伤组小鼠爬杆时间为（33±14）s，接近正常对照组水平（t=2．044，P〉0．05）；负重游泳时间为（47±12）min，明显短于正常常对照组（t=2．855，P〈0．05）。结论严重烧伤可导致小鼠体格发育不良、学习记忆能力和运动能力下降，同时使体内GH水平明显降低。

Objective To analyze the changes in body growth, learning and memory capabilities, exercise capacity, and the level of growth hormone （GH） in mice suffering from severe burn. Methods One hundred and four healthy BALB/c mice aged from 3 to 4 weeks were divided into normal control group （NC, without treatment）, 7 s burn group （inflicted with 20% TBSA deep partial-thickness burn on the back） , 10 s burn group （inflicted with 20% TBSA full-thickness burn on the back） , and negative control group （ simulating the treatment of two burn groups without injury） according to the random number table, with 26 mice in each group. The body weight, body length, and tail length of 8 mice in each group were measured before burn. Respectively 6 mice of two burn groups were sacrificed on post burn day （PBD） 1 , 3, and 7 for determination of serum level of GH with enzyme-linked immunosorbent assay kit. The remaining 8 mice in each of the two burn groups were raised to adulthood. The body weight, body length, and tail length were measured on PBD 62, and the increased percentages of body weight, body length, and tail length were calculated. Morris water maze tests, including escape latency on PBD 66, 67, and 68, frequen- cy of stepping over the platform location and proportion of staying time in the target quadrant on PBD 69, were used to examine the learning and memory capabilities. The time of loaded swimming and the time of pole-climbing on PBD 70 were used to assess the exercise capacity. Above-mentioned indexes were also de- termined in the two control groups at the same time points. Data were processed with one-way analysis of va- riance; Welch test was applied when equal variance was not assumed; independent samples t test was applied for paired comparison. Results （1） The level of GH of mice in 7 s burn group on PBD 1 [ （3 021 -＋ 506） pg/mL] was lower than that of group NC [（3 728 ＋412） pg/mL, t =2.656, P 〈0.05], while on PBD 3 and 7 [ （3 098 -＋503）, （3 199-＋275） pg/mL] they were close to those of group NC [ （3 872 -＋ 785）, （3 301 -＋600） pg/mL, with t values respectively 2. 033 and 0. 379, P values all above O. 05 ]. The levels of GH of mice in 10 s burn group on PBD 1, 3, and7 were respectively （2 859-＋447）, （2 707-＋ 151）, and （2 666 -＋ 222） pg/mL, which were lower than those of group NC （with t values respectively 3. 504, 3.571, 2. 429, P 〈 O. 05 or P 〈 0.01 ）. （2） The increased percentage of body weight, body length, and tail length of mice in group NC, 7 s burn group, and 10 s burn group were respectively （155 -＋ 22）%, （46_＋6）%, （63-＋10）%; （112-＋57）%, （32 ＋12）%, （40-＋15）%; （106-＋36）%, （30-＋ 8） % , （32 -＋ 7） %. The increased percentage of body weight of mice in 7 s burn group was close to that in group NC （ t = 1. 997, P 〉 0.05 ） , while the increased percentages of other indexes of mice in the two burn groups were lower than those in group NC （ with t values from 3. 092 to 6. 910, P values all below 0.01 ）. （3） The escape latency values of mice in 10 s burn group on PBD 67 and 68 were respectively （33 -＋ 12） , （33 -＋ 11 ） s, which were longer than those of group NC [ （20 -＋ 8 ）, （20 -＋ 7 ） s, with t values respectively 2. 421 and 2. 692, P values all below 0.05 ]. The frequency of stepping over the platform location of mice in 10 s burn group [（1.6-＋1.8） times] was close to that of group NC [（3.2-＋1.5） times, t =1.989, P 〉 0.05 ]. The proportion of retention time in the target quadrant of mice in 10 s burn group [ （ 28 -＋ 7 ） % ] was shorter than that of group NC[ （48 -＋ 16）%, t =3.076, P 〈0.01]. The escape latency of mice in 7 s burn group on PBD 67 [ （30 ＋ 7 ） s ] was longer than that of group NC （ t = 2. 659, P 〈 0.05 ）. The frequency of stepping over the platform location and the proportion of retention time in the target quadrant of mice in 7 s burn group [ （2.0 -＋ 1.1 ） times, （36 ＋ 11 ） % , respectively] were close to those of group NC （with t values respectively 1. 930, 1. 670, P values all above O. 05）. （4） The time of pole-climbing [ （30 -＋ 11 ） s] and the time of loaded swimming [ （38 -＋39） mini of mice in 10 s burn group were shorter than those of group NC [（47-＋11） s, （122-＋74） min, with t values respectively 3.108 , 2. 868,P 〈0.05 orP 〈0.01]. The time of loaded swimming of mice in 7 s burn group [ （47 -＋ 12 ） rain ] was shorter than that of group NC （ t = 2. 855, P 〈0.05）, while the time of pole-climbing [ （33 -＋ 14） s] was close to that of group NC （ t = 2. 044, P 〉 0.05）. Conclusions For mice, severe burn can delay body growth, decrease the learning and memory capabilities, decrease exercise capacities, and reduce the serum level of GH.