Objective To analyze the potential mechanism of preventive and therapeutic effects of 90Sr on hypertrophic scar,and to observe its clinical effect.Methods Fibroblasts isolated from human hypertrophic scar were cultured in vitro and radiated by 90Sr with the dose varying from 0 Gy ( control group)to 5 Gy ( LD group),10 Gy ( MD group),and 15 Gy ( HD group).The cell cycle and apoptosis rate were determined by flow cytometry at post radiation hour ( PRH ) 24,48,and 72,The concentration of type Ⅰ collagen in cell supernatant was detected by enzyme-linked immunosorbent assay ( ELISA ).Therapeutic effects of 90Sr radiation were evaluated among 348 patients with hypertrophic scars,40 patients with keloids,and 114 patients for scar prevention after surgical operation.The number of fibroblasts after HE staining was compared among normal skin tissue,hypertrophic scar,and hypertrophic scar treated with 90Sr radiation.Data were processed with one-way analysis of variance and q test,Results (1)Apoptotic rates in MD and HD groups at PRH 48 were higher than those at PRH 24,and the apoptotic rate was similar between MD group and HD group at PRH 72.Apoptotic rate in LD group at PRH 48 was significantly higher than that at PRH 24,but it decreased rapidly at PRH 72,which was significantly lower than those in MD and HD groups ( with F values all equal to 916.711,P values all below 0.01 ).( 2 ) At PRH 24,cell ratios of each phase in LD and HD groups were similar,and cell ratio of S phase in HD group [ (48.1 ± 1.0)％ ] was higher than those in the other three groups ( with F values all equal to 200.277,P values all below 0.01 ).At PRH 72,cell ratio of S phase in MD and HD) groups was respectively ( 85.7 ± 5.2 ) ％,( 73.0 ± 8.4 ) ％.implying that cells were blocked in S phase,and the values were all higher than those in control and LD groups ( with F values all equal to 111.105,P values all below 0.01 ).(3) At the same time point,the concentration of type Ⅰ collagen decreased along with the increase of radiation dose (with F values from 5044.449 to 8234.432,P values all below 0.01 ).With the same radiation dose,the concentration of type Ⅰ collagen increased along with prolongation of time (with F values from 333.395 to 2973.730,P values all below 0.01 ).(4) Clinical observation showed the (obvious) effective rate of radiation for pathological scars and that for scar prevention after surgical operation added up to 88.45％.The number of fibroblasts per 200 times visual field in patients after 90Sr radiation (86 ± 20) was less than that in patients without treatment [ ( 198 ± 65 ),F =208.405,P ＜ 0.05]. Conclusions The effect of 90 Sr radiation on fibroblasts and extracellular matrix can contribute to inhibition of scar formation,and the clinical effect is.significant.%目的 探讨90Sr防治瘢痕增生的作用机制并观察临床疗效. 方法 用90Sr敷贴器按照0、5、10,15 Gy剂量照射体外培养的人增生性瘢痕Fb.照射后24、48、72 h,流式细胞仪测定细胞周期及凋亡率变化,ELISA法检测细胞培养上清液中Ⅰ型腔原浓度.评价348例增生性瘢痕患者、40例瘢痕疙瘩患者及114例外科手术后瘢痕预防患者应用90Sr照射治疗的效果,并经HE染色对比正常皮肤组织、增生性瘢痕组织、经90SR照射治疗的增生性瘢痕组织中Fb数目.对数据进行单因素方差分析和q检验. 结果 (1)剂量为10、15 Gy的90Sr照射后24、48 h,细胞凋亡率呈逐渐上升趋势,至照射后72 h两者凋亡率相近.剂量为5 Gy的90Sr照射后48 h细胞凋亡率明显高于照射后24 h,但照射后72 h细胞凋亡率迅速下降,与剂量为10、15 Gy时比较差异均有统计学意义(F值均为916.711,P值均小于0.01).(2)照射后24h,90Sr照射剂量为5、10 Gy时,细胞各周期的百分比相近；90Sr照射剂量为15 Gy时,S期细胞明显增多[(48.1±1.0)％,F值均为200.277,P值均小于0.01].剂量为10 Gy及15 Gy的90Sr照射后72 h,细胞明显阻滞在S期,S期细胞百分比分别为(85.7±5.2)％、(73.0±8.4)％,与照射剂量为0 Gy和5 Gy时比较差异均有统计学意义(F值均为111.105,P值均小于0.01).(3)同一照射时相点下,照射剂量越大,Ⅰ型胶原浓度越低(F值为5044.449～8234.423,P值均小于0.01).同一照射剂量下,随着时间推移,Ⅰ型胶原浓度有不同程度的增加(F值为333.395～2973.730,P值均小于0.01).(4)临床病例观察显示,90Sr照射病理性瘢痕或术后瘢痕预防患者后,显效率及有效率累计88.45％.HE染色显示,90Sr照射治疗的人增生性瘢痕Fb数目[每200倍视野(86±20)个]少于未经照射治疗者[每200倍视野(198±65)个,F=208.405,P＜0.05]. 结论 90Sr抑制瘢痕的生长是其对瘢痕Fb和ECM共同作用的结果,且临床疗效显著.
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