细胞周期正负调控因子在伤口愈合中的表达规律及意义

目的：伤口愈合是细胞增生受到严密调控的过程。细胞生长取决于细胞周期正负调控因子间的相互作用及平衡。本研究通过测定伤口愈合过程中细胞周期正向调控因子CyclinD1、CyclinE、CDK2、CDK4及负向调控因子p21^cipl、p27^kipl、p16^ink4a、p15^ink4b的表达变化，旨在探讨愈合过程中生长调控机制及意义。方法：采用大鼠全皮层开放伤模型，收集伤后3-30日伤口组织，以免疫组织化学法测定Ki67的表达，Western blot法检测CyclinD1、CyclinE、CDK2、CDK4及p21^cipl、p27^kipl、p16^ink4a、p15^ink4b。结果：细胞生长主要发生在伤后一周之内，生长高峰出现在伤后5日。CyclinD1、CDK2、CDK4的表达均保持较为恒定的水平，整个愈合过程无明显的起伏变化；伤后3-11日，CyclinE呈高表达，14日开始明显下降，伤后21-30日几乎回落到伤前水平。Western blot法未检测到p16^ink4a、p15^ink4b的表达；p21^cipl在伤后7-14日呈一过性表达，其峰值水平出现在伤后9日；p27^kipl呈结构性表达，伤后3-5日表达强度相对低下，随后大幅度上调。P21^cipl、p27^kipl表达确与Ki67的表达呈反向趋势。结论：伤口愈合过程中，p21^cipl、p27%kipl在防止过度增生趋势中发挥着监控作用，其中p27^kipl的作用更为重要。

Expression of positive and negative regulators of cell cycle during wound healing

Objective To detect the expression of cell cycle positive regulators cyclin D1, cyclin E, CDK2, CDK4 and negative regulators p21cip1, p27kip1, p16ink4a and p15ink4b during wound healing in rats. Methods Open wounds of full-thickness skin, diameter 1.8?cm, on rat backs were used as the wound model. Wound tissues were harvested on postwounding days 3, 5, 7, 9, 11, 14, 21 and 30. Ki67 expression in granulation tissue was detected by immunohistochemical assay. The patterns of the expression of cyclin D1, cyclin E, CDK2, CDK4 and p21cip1, p27kip1, p16ink4a, p15ink4b were detected by Western blot. Results Cell proliferation in granulation tissue took place predominantly within the first week after injury, with the proliferation peak occurring at postwounding day 5. There were no dramatic variations in the expression of cyclin D1, CDK2 and CDK4 during wound healing. Up-regulated cyclin E was maintained from day 3 to 11 after injury, and then was down-regulated. No expression of p16ink4a and p15ink4b was found. p21cip1 was expressed only from day 7 to 14, with peak expression observed on day 9. Constitutive p27kip1 was expressed throughout wound healing with low levels in the proliferating period of day 3 to 5 and with increased levels in the post-mitotic and remodeling stage. The expression of p21cip1 and p27kip1 showed an inverse gradient to that of Ki67.Conclusion p21cip1 and p27kip1 play a supervising role in preventing the hyperproliferative tendency in tissue repair.