OBJECTIVETo investigate the effects of botulinum toxin type A (BTXA) on the expression of alpha smooth muscle actin(alpha-SMA) and myosin-II of fibroblasts in scars. Methods Fibroblasts were isolated from tissue specimens of scars contracture. Cells from passages 3-5 were randomly divided into 3 groups (control group, low BTXA group (1 U/10(6) Cells), and high BTXA group (2.5 U/ 10(6)Cells)). Growth condition of fibroblasts was observed at 1 , 4, 7 day after BTXA treated. Changes of alpha-SMA and myosin-II in fibroblasts were detected by Western blot.

RESULTSFibroblasts grew well in control group. The proliferation was decreased 4 days later in BTXA groups. Lots of apoptotic cells were seen in high BTXA group at 7th day. Proteins of alpha-SMA and myosin-II in fibroblasts were statistically different between BTXA group and control groups at 4th day (P < 0.05). The expression of alpha-SMA and myosin-II in low BTXA group was higher than that in high BTXA group at 7th day (P < 0.05).

CONCLUSIONSBTXA could induce the apoptosis of fibroblasts and decrease the expression of alpha-SMA and myosin-II in fibroblasts. The inhibitory effect was strengthened with BTXA concentration increase within a certain range.

Actins ; metabolism ; Botulinum Toxins, Type A ; pharmacology ; Cicatrix ; Fibroblasts ; drug effects ; metabolism ; Humans ; Muscle, Smooth ; metabolism ; Myosin Type II ; metabolism ; Random Allocation

Objective To evaluate the validity of botulinum toxin type A (BTXA) injections for the treatment of scar contracture.Methods 26 patients with scar contracture were randomly assigned into BTXA group and triamcinolone acetonide (TAC) group.Pinpoint tattooing was performed on each side of each scar in the plane of its longest axis.A template was used to ensure consistent length.These two tattoo points were measured to assess scar contraction at baseline,at every month for a total of 6 months.Histological analysis was conducted to study the physiological environment and immunohistochemistry to detect the expression of α-SMA and myosin-Ⅱ at different groups.Results Scar contraction was more relaxed in BTXA group than that in TAC group after 1 month (P＜0.05),especially in the 6th month (the D value in BTXA group and TAC group was (1.23±0.42) cm,and (0.56±0.33) cm respectively).For immunohistochemistry,the expression of α-SMA and myosin-Ⅱ also decreased in BTXA group (P＜0.05).Conclusions The treatment of scar contracture by suitable BTXA injections is safe and effective.

Objective:To understand the current situation and problems of pediatric drug clinical trials in China, and provide reference for the healthy development of pediatric drug clinical trials.Methods:Such keywords as " pediatrics" " children" " annual reports" " children′s drug research and development" " policies" were used, to search for information on China′s pediatric drug research and development policies and regulations, pediatric drug clinical trial institutions and pediatric drug clinical trial professional registration status, as well as pediatric drug clinical trial project registration status as of October 2023 on the drug clinical trial institution registration management information platforms and relevant government department websites. Then descriptive analysis was made on the collected information.Results:China has released 9 policies and regulations on pediatric drug research and development, supporting the development of new varieties, dosage forms, and specifications of pediatric drugs that meet the physiological characteristics of children, and giving priority review and approval to pediatric drugs. 477 drug technology guiding principles have been released, but only 14 of them were specifically designed for pediatric populations. As of March 20, 2023, there were a total of 272 registered pediatric drug clinical trial institutions, accounting for 20.72% of the total number of registered institutions. The top 5 provinces for their number of registered institutions were Guangdong province (34), Henan province (21), Zhejiang province (20), Beijing (20), and Jiangsu province (18); A total of 26 clinical trial specialties for pediatric drugs have been registered, with the largest number of registrations being pediatric respiratory (143), pediatric hematology (72), pediatrics other (71), pediatric endocrinology (68), and pediatric neurology (64). From 2020 to 2022, the proportion of pediatric drug clinical trial registration projects in newly registered drug clinical trials was 8.8% (129/1 473), 8.3% (168/2 033), and 8.3% (164/1 974), respectively, while clinical trials conducted only in the pediatric population accounted for 2.2% (33/1 473), 3.0% (61/2 033), and 3.2% (64/1 974), respectively.Conclusions:The policies and regulations on pediatric drug research and development in China still need further improvement. The number of registered pediatric drug clinical trial institutions and pediatric specialties is lower than that of adults and distributed unevenly. Clinical trial registration projects for pediatric drugs, especially those conducted in the pediatric population, account for a relatively small proportion. It is recommended to further improve the policy system for drug research and development in the pediatric population, optimize the layout of pediatric drug clinical trial institutions and specialties in the country.