A型肉毒毒素在大鼠硅胶假体包膜形成中的作用与机制探讨

Effect and mechanism of botulinum toxin type A on cat capsular formation of silicone prosthesis

目的 探讨A型肉毒毒素(botulinum toxin type A,BTX-A)注射对大鼠体内置入聚二甲基硅氧烷(polydimethylsiloxane,PDMS)后包膜形成的影响作用与机制。方法 2021年2月至2022年4月,陆军军医大学第二附属医院整形外科,将40只大鼠随机分为1.0 U组、2.5 U组、5.0 U及对照组,大鼠背部正中线两侧各取2个点,每点置入1 cm×1 cm PDMS,术后即刻在置入部位注射1.0、2.5、5.0 U的BTX-A和0.1 ml生理盐水(对照组),3个月后超高分辨率超声影像系统(HR-US)检测置入部位假体周围纤维组织厚度,随后对包膜组织行HE染色、Masson染色、免疫组化染色,并通过H-score半定量分析各组α平滑肌激动蛋白(α-smooth muscle actin, α-SMA)、Ⅰ型胶原(typeⅠcollagen protein, COL-Ⅰ)、Ⅲ型胶原(type Ⅲ collagen protein, COL-Ⅲ)和增殖细胞核抗原(proliferating cell nuclear antigen, PCNA)的差异。细胞实验中向人成纤维细胞分别加入完全培养基和含BTX-A浓度为2.0、5.0、10.0 U/ml的完全培养基,培养72 h后CCK-8法检测细胞增殖活性,Western blot检测PCNA和α-SMA的表达量。结果 与对照组相比,HR-US结果显示,5.0 U BTX-A显著减小包膜厚度(P<0.05),HE染色结果显示1.0 U组、2.5 U组、5.0 U组包膜厚度均减少(P<0.05)。HR-US和HE染色测量结果间具有相关性(P<0.05);免疫组化分析结果显示,各组间COL-Ⅰ、COL-Ⅲ和PCNA无明显差异,2.5 U和5.0 U BTX-A组α-SMA表达量明显下降(P<0.05)。实验中细胞增殖活性略有下降,PCNA和α-SMA表达量有减少的趋势,但差异无统计学意义。结论 5.0 U BTX-A通过减少α-SMA抑制成纤维细胞向肌成纤维细胞转化,从而减小包膜厚度。同时,将超声检测作为临床上诊断包膜挛缩的补充检查,有一定的临床应用前景。

Objective To investigate the effect and mechanism of botulinum toxin type A(BTX-A) injection on capsular formation of polydimethylsiloxane(PDMS) in rats. Methods From February 2021 to April 2022, all rats were divided into 1.0 U group, 2.5 U group, 5.0 U group and control group. Two points were taken on both sides of midline at the back of rat, and PDMS of 1 cm × 1 cm was implanted in each point. Immediately after surgery, 1.0 U, 2.5 U, 5.0 U BTX-A and equal volume of normal saline were injected into the implantation site. Three months later, high-resolution small animals ultrasound imaging system(HR-US) was used to detect the thickness of fibrous tissue around the implantation site. HE staining, Masson’s trichrome staining and immunohistochemical staining of capsular tissue and H-score semi-quantitative analysis of differences of α-SMA, COL-Ⅰ, COL-Ⅲ and PCNA were performed. Adding complete culture medium and complete culture medium containing 2.0 U, 5.0 U and 10.0 U/m L BTX-A to human fibroblasts. After 72 h of culture,the proliferation was detected by CCK-8 and the expression of PCNA and α-SMA was detected by Western blot. Results Compared with the control group, the results of HR-US showed that 5.0 U BTX-A significantly reduced the capsule thickness(P<0.05). The HE staining results showed that the capsule thickness in the 1.0 U, 2.5 U and 5.0 U group decreased(P<0.05). There was a correlation between HR-US and HE staining results(P<0.05). The immunohistochemical analysis showed that there was no significant difference in COL-Ⅰ,COL-Ⅲ and PCNA among three groups. The α-SMA expression in the 2.5 U and 5.0 U BTX-A group was significantly decreased(P<0.05). The proliferation of cells decreased slightly, and the expression of PCNA and α-SMA tended to decrease, but the differences were not statistically significant. Conclusion The BTX-A of 5.0 U may reduce capsule thickness by decreasing α-SMA and inhibiting the transformation of fibroblasts into myofibroblasts. At the same time, as a supplementary examination for clinical diagnosis of capsular contracture, ultrasound detection has a certain clinical application prospect.