重组人血小板源性生长因子增加细胞外信号调节激酶磷酸化促进糖尿病大鼠全层皮肤缺损创面愈合

目的 在体观察重组人血小板源性生长因子（recombinant human platelet—derived growth factor，rhPDGF）促进糖尿病大鼠全层皮肤缺损创面修复可能涉及的细胞和分子机制，研究其可能涉及的信号通路。方法 26只糖尿病大鼠，每只动物背部制备4个全层皮肤缺损创面，选取其中52个创面，随机分成3组，即对照组，创面自然愈合；rhPDGF治疗组，创面rhPDGF用量为7．0μg／cm^2；赋形剂组，创面用等量赋形剂凝胶。观察治疗后3、7和14d创面肉芽形成、胶原沉积、再上皮化速率以及炎性细胞浸润情况，并采用免疫荧光和免疫组织化学技术观察创面周围和创面修复细胞内细胞外信号调节激酶1／2（extracellular signal—regulated kinase1／2，ERK1／2）磷酸化和增殖细胞核抗原（proliferative cell nuclear antigen，PCNA）的表达。结果 组织学观察，rhPDGF治疗组创面可见大量炎性细胞浸润，毛细血管胚芽及成纤维细胞明显多于另两组（P〈0．05）；胶原沉积明显，肉芽组织生长活跃，创面收缩显著，与对照组比较差异有统计学意义（P〈0．05）。免疫学研究显示，应用rhPDGF7～14d后，rhPDGF治疗组ERK1／2明显强于对照组和赋形剂组（P〈0．05）；且损伤后3～7d rhPDGF治疗组修复细胞PCNA的表达明显高于对照组和赋形剂组（P〈0．05）。结论 rhPDGF促糖尿病大鼠刨面愈合的作用部分是通过ERK1／2信号通路的磷酸化来完成的。

Recombinant Human Platelet-derived Growth Factor Enhances Repair of Cutaneous Full-thickness Excision by Increasing the Phosphorylation of Extracellular Signal-regulated Kinase in Diabetic Rat

OBJECTIVE: To investigate the possible signaling mechanisms by which recombinant human platelet-derived growth factor (rhPDGF) accelerated healing of cutaneous wound in diabetic rats. METHODS: Four full-thickness skin wounds were incised in the back of 26 male Wistar diabetic rats. The wounded rats were divided into 3 groups (7 or 8 rats each group). One group without treatment was used as a control, and the other 2 groups were treated with rhPDGF at a dose of 7.0 microg/cm2 wound or vehicle (DMSO/0.9% NaCl, vol/vol 1:1) from 1 to 14 days. The wound healing was evaluated by the measurements of the wound volume and area. Immunofluorescent and immunohistochemical staining were used to examine the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and the expression of proliferative cell nuclear antigen (PCNA), respectively. RESULTS: Granulation tissue appeared in the bed of wound after injury. The number of blood capillary buds and fibroblasts was greater in the rhPDGF-treated group than that in the other 2 groups. A lot of inflammatory cells infiltration and collagen deposition were observed in the wound. The wound-volume in the rhPDGF-treated group was smaller than that in control group (P < 0.05). The reepithelialization rate in rhPDGF-treated group was higher than that in the other 2 groups at 7 days after injury (P < 0.05). The expression of PCNA in reparative cells was higher in rhPDGF-treated group than in control group or vehicle-treated group at 3,7 days after injury (P < 0.05). The phosphorylation of ERK1/2 was stronger in rhPDGF-treated group than that in control group or vehicle group at 7 and 14 days after injury (P < 0.05). CONCLUSION: These results suggest that rhPDGF accelerates wound healing and improves healing quality by increasing the phosphorylation of ERK1/2.