Jiang Nanhong, Xie Weiguo, Wang Hui, Jin Dongmei, Tan Hong, Zhao Chaoli
Institute of Burns, Wuhan City Hospital No.3 & Tongren Hospital of Wuhan University, Wuhan 430060, China.
Institute of Burns, Wuhan City Hospital No.3 & Tongren Hospital of Wuhan University, Wuhan 430060, China. Email:
Zhonghua Shao Shang Za Zhi. 2014 Apr;30(2):128-33.
To observe the effects of low molecular weight heparin (LMWH) on the inflammatory response and vascular injury in rat after electric burn.
A homemade regulator and transformer apparatus was used to reproduce the model of electric burn (0.5 cm×0.5 cm in size) with depth from full-thickness to full-thickness skin plus muscle and bone on the middle of the inside of right hind limb in 60 Wistar rats. The open wounds were covered with 20 g/L sulfadiazine silver paste immediately after injury. The wound condition was observed every day. The injured rats were divided into group LMWH and control group (C) according to the random number table, with 30 rats in each group. Rats in group LMWH were given subcutaneous injection of LMWH (1 U/g) in abdominal wall, 2 times a day. No other treatment was given in rats in group C. On post burn day (PBD) 3, 5, and 10, 10 rats respectively of two groups were sacrificed. The damaged tissue of wound and that around the wound (1.0 cm×0.5 cm in size) were excised, and heart blood was obtained. The pathological changes and thrombosis in damaged tissue were observed with HE, Masson, and aldehyde fuchsin staining, and the thrombosis rate was calculated. Serum contents of TNF-α and endothelin-1 were determined with ELISA. The mRNA expression of TNF-α in damaged tissue was detected with RT-PCR. Data were processed with Levene homogeneity test, analysis of variance of factorial design, LSD- t test, SNK- q test, and Friedman M nonparametric test.
(1) The injured limb of rats was obviously swollen after electric burn, which reached deeply to the muscle and bone. Compared with those of group C, the swelling of rats subsided slightly faster and the inflammatory response was lighter in group LMWH at each time point. (2) The necrosis of damaged tissue and profuse infiltration of inflammatory cells were observed. Dilatation of blood vessels, congestion and thrombosis, and swelling, necrosis, and desquamation of vascular endothelial cells were observed in the damaged tissue. Damaged blood vessel wall, ruptured elastic fiber, loss of internal elastic membrane, and other pathological changes were observed in the damaged tissue of rats in the two groups. Above lesions were improved gradually along with the passage of time, and the improvement was more obvious in rats of group LMWH compared with that of group C on PBD 5 and 10. (3) The thrombosis rates of rats in group LMWH were obviously lower than those of rats in group C (F = 4.921, P < 0.05). The thrombosis rates of rats in group LMWH on PBD 3 and 10 were respectively (0.07 ± 0.11)% and (0.03 ± 0.05)%, which were significantly lower than those of rats in group C [(0.16 ± 0.15)% and (0.13 ± 0.18)%, with t values respectively 2.17 and 2.07, P values below 0.05]. In group LMWH, the thrombosis rate of rats on PBD 10 was obviously lower than that on PBD 3 (t = 3.61, P < 0.05). (4) The serum contents of TNF-α and endothelin-1 of rats in group LMWH were significantly lower than those of rats in group C (F = 47.161, χ(2) = 81.46, P values below 0.01). In group LMWH, TNF-α contents were respectively (71 ± 24), (74 ± 14), (72 ± 20) pg/mL, and endothelin-1 contents were respectively (20.9 ± 3.2), (19.8 ± 5.2), (18.6 ± 1.1) ng/mL on PBD 3, 5, and 10, and they were significantly lower than those of rats in group C [(195 ± 148), (96 ± 20), (159 ± 46) pg/mL and (38.8 ± 15.4), (27.9 ± 3.6), (25.6 ± 7.6) ng/mL, with t values from 3.81 to 8.05, q values from 4.41 to 7.85, P < 0.05 or P < 0.01]. (5) The mRNA expression levels of TNF-α in damaged tissue of rats in group LMWH were significantly lower than those of rats in group C (F = 199.113, P < 0.01). The mRNA expression levels of TNF-α of rats in group LMWH were respectively 0.93 ± 0.10, 1.15 ± 0.12, 1.21 ± 0.11 on PBD 3, 5, and 10, and they were significantly lower than those of group C (1.68 ± 0.15, 1.43 ± 0.12, 1.50 ± 0.13, with t values from 3.75 to 6.12, P < 0.05 or P < 0.01). In group LMWH, the mRNA expression level of TNF-α of rats on PBD 10 was obviously higher than that on PBD 3 (t = 3.61, P < 0.05).
LMWH intervention can ameliorate vascular injury and inflammatory response of electrically burned wounds in rats, and it decreases thrombosis rate in the vessels of injured limb.
观察低分子肝素（LMWH）对大鼠电烧伤后炎症反应及血管损伤的影响。
采用自制的调节器和变压器装置，在60只Wistar大鼠右后肢内侧中部制作电烧伤模型（大小为0.5 cm×0.5 cm），深度从全层皮肤至全层皮肤加肌肉和骨骼。伤后立即用20 g/L磺胺嘧啶银糊剂覆盖开放伤口。每天观察伤口情况。根据随机数字表将受伤大鼠分为LMWH组和对照组（C组），每组30只。LMWH组大鼠于腹壁皮下注射LMWH（1 U/g），每日2次。C组大鼠不给予其他处理。在烧伤后第3、5和10天，分别处死两组中的10只大鼠。切除伤口及伤口周围（大小为1.0 cm×0.5 cm）的损伤组织，并采集心脏血液。采用HE、Masson和醛复红染色观察损伤组织的病理变化及血栓形成情况，并计算血栓形成率。采用ELISA法测定血清肿瘤坏死因子-α（TNF-α）和内皮素-1含量。采用RT-PCR法检测损伤组织中TNF-α的mRNA表达。数据采用Levene方差齐性检验、析因设计方差分析、LSD-t检验、SNK-q检验和Friedman M非参数检验进行处理。
（1）大鼠电烧伤后伤肢明显肿胀，深达肌肉和骨骼。与C组相比，LMWH组大鼠在各时间点肿胀消退稍快，炎症反应较轻。（2）观察到损伤组织坏死及大量炎症细胞浸润。损伤组织中可见血管扩张、充血和血栓形成，以及血管内皮细胞肿胀、坏死和脱落。两组大鼠损伤组织均观察到血管壁损伤、弹性纤维断裂、内弹力膜丧失等病理变化。上述病变随时间推移逐渐改善，与C组相比，LMWH组大鼠在烧伤后第5天和第10天改善更明显。（3）LMWH组大鼠的血栓形成率明显低于C组（F = 4.921，P < 0.05）。LMWH组大鼠在烧伤后第3天和第10天的血栓形成率分别为（0.07±0.11）%和（0.03±0.05）%，明显低于C组[（0.16±0.15）%和（0.13±0.18）%，t值分别为2.17和2.07，P值均< 0.05]。在LMWH组中，大鼠在烧伤后第10天的血栓形成率明显低于第3天（t = 3.61，P < 0.05）。（4）LMWH组大鼠血清TNF-α和内皮素-1含量明显低于C组（F = 47.161，χ(2) = 81.46，P值均< 0.01）。在LMWH组中，烧伤后第3、5和10天TNF-α含量分别为（71±24）、（74±14）、（72±20）pg/mL，内皮素-1含量分别为（20.9±3.2）、（19.8±5.2）、（18.6±1.1）ng/mL，均明显低于C组[（195±148）、（96±20）、（159±46）pg/mL和（38.8±15.4）、（27.9±3.6）、（25.6±7.6）ng/mL，t值为3.81至8.05，q值为4.41至7.85，P < 0.05或P <
