糖基化终末产物对糖尿病大鼠烧伤创面愈合的影响

目的 了解糖基化终末产物(AGE)蓄积对糖尿病大鼠烧伤创面愈合的影响. 方法 将75只SD大鼠按完全随机化方法 分为对照组、糖尿病组及氨基胍干预组,每组25只.将大鼠造成深Ⅱ度烫伤(以下称烧伤)后,后2组制作成糖尿病模型,氨基胍干预组给予管饲氨基胍100 mg·kg~(-1)·d~(-1).于伤后0(伤后当天)、3、7、14、21 d处死大鼠.描取创面形状,并取全层皮肤组织待测.同时取大鼠背部表皮行KC培养及鉴定.观察各组创面愈合率及皮肤组织糖含量,创面组织形态学变化,皮肤组织中AGE分布.观察不同浓度AGE对KC增殖,凋亡的影响,以仅加表皮细胞培养液的KC为对照组. 结果 伤后7、14、21 d糖尿病组创面愈合率显著低于对照组(P<0.01),而氨基胍干预组却明显高于前2组(P<0.01).糖尿病组皮肤组织含糖量为(2.62±0.19)mmol/g,氨基胍干预组为(2.58±0.07)mmol/g,均高于对照组(1.04±0.09)mmol/g(P<0.01).对照组大鼠创面炎性细胞浸润强烈而局限,坏死组织形成、脱落及时,创面愈合无明显延迟;糖尿病组大鼠炎性细胞浸润缓慢、弥散而持久,坏死组织形成、脱落较迟,创面愈合明显延迟;氨基胍干预组大鼠炎性细胞浸润及时、强烈,坏死组织形成、脱落以及创面愈合时间较糖尿病组早.对照组中有少量散在的AGE沉积,糖尿病组AGE蓄积显著增加,而氨基胍干预组AGE含量显著降低.AGE作用48 h后,KC的增殖显著降低,呈现浓度依赖性,各剂量AGE干预组的吸光度值均低于对照组(P<0.01).100μg/mLAGE干预组KC早期凋亡连接素V阳性细胞比例为(15.1±2.3)%,明显高于对照组(11.2±1.2)%,P<0.05];终未期凋亡双阳性细胞比例为(14.3±3.5)%,与对照组(15.2±2.4)%比较,差异无统计学意义(P>0.05). 结论 高血糖可能是通过AGE蓄积,抑制KC等修复细胞增殖导致创面难愈;减少AGE蓄积,可改善糖尿病创面愈合延迟现象.

Influence of advanced glycosylation end products on wound healing of burn rats with diabetes

Objective To understand the influence of accumulation of advanced glycosylation end Droducts (AGE) on wound healing of burn rats complicated with diabetes. Methods Seventy-five SD rats were divided into control, diabetes. and aminoguanidine-interfered groups in completely randomized method.with 25 rats in each group.All rats were subjected to deep partial-thickness scald.Diabetes was re-produeed in rats of diabetes and aminoguanidine-interfered groups.were fed with 100 mg·kg~(-1)·d~(-1) aminoguanidine.Rats in aminoguanidine-interfered group 14,and 21,and potraits of the wounds were taken. Full-thickness skin tissue specimens were obtained for determination.Specimens of epidermis from back of SD rats were obtained for KC cultivation and verifica-tion.Wound healing rate,glucose content in skin tissue,morphologic change in wound tissue,AGE distri-bution in skin tissue.influence of AGE on proliferation and apoptosis of KC were observed. Results Wound healing rate of rats was respectively lower in diabetes group than that in control group on PSD 7,14,and 21(P<0.01),but it was obviously higher in aminoguanidine-interfered group than that in the former 2 groups(P<0.01).Glucose content of rat skin in diabetes group was(2.62±0.19)mmol/g,and it was (2.58±0.07)mmol/g in aminoguanidine-interfered group,both higher than that in control group (1.04±0.09)mmol/g,P<0.01].In control group,limited intensive infiltration of inflammatory cells was found in the wound with necrotic tissue formation which fell off in time,and with no obvious delav of wound healing.In diabetes group,infiltration of inflammatory ceils in wounds of rats appeared slowly,but diffusely and persistently:necrotic tissue formed and fell off late in time.with obvious delay of wound heal-ing. In aminoguanidine-interfered group, intensive infiltration of inflammatory cells was observed in time,and the time of necrotic tissue formation and sloughing,and wound healing were respectively earlier than that in diabetes group.Sporadical disposition of small amount of AGE was found in rats in control group.AGE accumulation increased significantly in rats in diabetes group.AGE content decreased significantly in rats in aminoguanidine-interfered group after administration of aminoguanidine.KC proliferation decreased signifi-cantly in concentration dependent manner 48 hours after AGE stimulation.Absorbance value of AGE de-creased in each AGE-interfered group(P<0.01).Early Annexin-V positive apoptotie KC rate was obvi-ously higher in 100 ug/mL AGE-interfered group(15.1±2.3)% than that in control group(11.2±1.2)%,P<0.05].There was no statistical significance between 100 ug/mL AGE-interfered group (14.3±3.5)%and control group(1 5.2±2.4)%in respect of the rate of double.positive cells apoptosis at final stage(P>0.05). Conclusions Hyperglycemia may inhibit proliferation of repairing cells such as KC through AGE accumulation,thus impedes wound healing.Reduction of AGE accumulation could a-meliorate wound healing delay due to diabetes.