探讨LED红光照射对糖尿病大鼠创面愈合的作用及相关机制。

将30只4周龄雄性SD大鼠按随机数字表法分为正常创面组、糖尿病创面组、红光治疗糖尿病创面组，每组10只。红光治疗糖尿病创面组及糖尿病创面组大鼠高脂饮食4周，正常创面组大鼠正常饮食。饲养4周后对红光治疗糖尿病创面组及糖尿病创面组大鼠按50 mg/kg的量腹腔注射10 mg/mL的链脲佐菌素(STZ)制作糖尿病大鼠模型，2组大鼠均造模成功。造模成功后在3组大鼠的背部两侧各制造2个1.5 cm×1.5 cm的全层皮肤缺损创面，每2 d对大鼠创面进行酒精消毒1次，红光治疗糖尿病创面组大鼠每次消毒后对创面进行LED红光照射5 min，能量密度为20 J/cm²，另外2组大鼠不进行LED红光照射。在观察第7、10、14、21天，观察红光治疗糖尿病创面组大鼠创面有无出现皮疹、红肿、水疱、烫伤等光照不良反应；肉眼观察3组大鼠创面愈合情况；统计3组大鼠创面愈合率。观察第10天从各组随机取2只大鼠，处死后取背部创面组织，固定后，进行苏木精-伊红染色观察创面新生血管情况及肉芽组织生长情况；采用免疫荧光法检测各组大鼠创面组织中CD34、血管内皮细胞生长因子(VEGF)表达情况。数据比较采用单因素方差分析和LSD-t检验。

观察第7、10、14、21天，红光治疗糖尿病创面组大鼠经LED红光照射后皮肤未见皮疹、红肿、水疱、烫伤等光照不良反应。在各个观察时间点，肉眼观察正常创面组及红光治疗糖尿病创面组创面愈合情况均优于糖尿病创面组，且正常创面组创面愈合情况略优于红光治疗糖尿病创面组；观察第7、10、14、21天，正常创面组的创面愈合率分别为(34.62±2.116)%、(53.83±7.92)%、(70.20±5.41)%、(95.65±2.58)%，红光治疗糖尿病创面组创面愈合率分别为(31.76±2.44)%、(50.48±4.54)%、(66.26±11.35)%、(93.96±2.80)%，糖尿病创面组创面愈合率分别为(23.67±4.18)%、(42.71±3.40)%、(53.77±7.74)%、(84.07±4.43)%，3组比较差异均有统计学意义(F＝34.69、10.35、10.32、34.40，P<0.05)；观察第7、10、14、21天，正常创面组及红光治疗糖尿病创面组创面愈合率始终高于糖尿病创面组，差异均有统计学意义(P<0.05)；观察第7、10天，正常创面组创面愈合率高于红光治疗糖尿病创面组，差异均有统计学意义(t＝2.80、3.26，P<0.05)，观察第14、21天，正常创面组创面愈合率仍高于红光治疗糖尿病创面组，但差异均无统计学意义(t＝1.16、1.40，P>0.05)。观察第10天，创面组织苏木精-伊红染色显示，正常创面组内含大量新生毛细血管，肉芽组织内胶原及细胞排列紧密有序；红光治疗糖尿病创面组见较多新生毛细血管，肉芽组织内胶原及细胞较多，但少于正常创面组；而糖尿病创面组新生血管最少，肉芽组织内细胞及胶原稀疏。免疫荧光法检测创面组织中CD34、VEGF表达情况可见，正常创面组CD34、VEGF表达高于红光治疗糖尿病创面组，而红光治疗糖尿病创面组表达高于糖尿病创面组。

LED红光可促进糖尿病大鼠创面组织中CD34、VEGF表达，促进血管新生，进而促进创面愈合。

To investigate the effect and related mechanism of LED red light irradiation on wound healing in diabetic rats.

Thirty 4-week-old male SD rats were divided into 3 groups, normal wound group, diabetic wound group, and diabetic wound treated with red light group according to the random number table method, with 10 rats in each group. The rats in diabetic wound treated with red light group and diabetic wound group had a high-fat diet for 4 weeks, and the rats in the normal wound group had a normal diet. After 4 weeks, the rats in the diabetic wound treated with red light group and the diabetic wound group were intraperitoneally injected with 10 mg/mL Streptozotocin (STZ) at a dose of 50 mg/kg to make diabetes models and both groups of rats were successfully modeled. After successful modeling, two full-thickness skin defect wounds of 1.5 cm×1.5 cm were made on both sides of the backs of the three groups of rats, and the wounds of the rats were disinfected with alcohol every two days, and the wounds of the rats in the diabetic wound treated with red light group were irradiated with LED red light at energy density of 20 J/cm² for 5 minutes after the disfection, the other two groups of rats were not irradiated with LED red light. On the 7th, 10th, 14th, and 21st days of observation, whether there were rashes, redness, blisters, scalds and other adverse light reactions on the wounds of the rats in the diabetic wound treated with red light group were observed, the wound healing condition of the three groups of rats was observed by naked eye, and the wound healing rate of the three groups of rats was counted. On the 10th day of observation, 2 rats were randomly selected from each group, and the back wound tissue was taken after being sacrificed. After fixation, hematoxylin-eosin staining was performed to observe the condition of new blood vessels and the growth of granulation tissue on the wound surface; the expressions of CD34 and vascular endothelial growth factor (VEGF) in wound tissue of rats in each group were detected by immunofluorescence method. Data were compared with one-way ANOVA and LSD-t test.

On the 7th, 10th, 14th, and 21st days, the rats in the diabetic wound treated with red light group were irradiated with LED red light, and there were no adverse light reactions such as rash, redness, blisters, and burns on the skin. At each observation time point, the wound healing of the normal wound group and the diabetic wound treated with red light group was better than that of the diabetic wound group by naked eye observation, and the wound healing of the normal wound group was slightly better than that of the diabetic wound treated with red light group. On the 7th, 10th, 14th, and 21st days of observation, the wound healing rates of the normal wound group were (34.62±2.116)%, (53.83±7.92)%, (70.20±5.41)%, and (95.65±2.58)%, the wound healing rates of the diabetic wound treated with red light group were (31.76±2.44)%, (50.48±4.54)%, (66.26±11.35)% and (93.96±2.80)%, and the wound healing rates of the diabetic wound group were (23.67±4.18)%, (42.71±3.40)%, (53.77±7.74)%, (84.07±4.43)%, respectively, the differences between the three groups were statistically significant (F=34.69, 10.35, 10.32, 34.40; P<0.05). On the 7th, 10th, 14th, and 21st days of observation, the wound healing rates of the normal wound group and the diabetic wound treated with red light group were always higher than those of the diabetic wound group, and the differences were statistically significant (P<0.05). On the 7th and 10th days of observation, the wound healing rates of the normal wound group were higher than those of the diabetic wound treated with red light group, and the differences were statistically significant (t=2.80, 3.26; P<0.05). On the 14th and 21st days of observation, the wound healing rates of the normal wound group were still higher than those of the diabetic wound treated with red light group, but the differences were no statistically significant (t=1.16, 1.40; P>0.05). On the 10th day of observation, hematoxylin-eosin staining of the wound tissue showed that the normal wound group contained a large number of new capillaries, and the collagen and cells in the granulation tissue were arranged in a tight and orderly manner; the diabetic wound treated with red light group saw some new capillaries, there were lots of collagen and cells in the granulation tissue, but less than that in the normal wound group; while the diabetic wound group had the least amount of new blood vessels, and the cells and collagen in the granulation tissue were sparse. The expressions of CD34 and VEGF were observed by immunofluorescence, the expressions of CD34 and VEGF in the normal wound group were higher than those of the diabetic wound treated with red light group, while the expressions of CD34 and VEGF in the diabetic wound treated with red light group were higher than those of the diabetic wound group.

LED red light can promote the expression of CD34 and VEGF in the wound tissue of diabetic rats, promote angiogenesis, and then promote wound healing.