The Direct Skin Rejuvenation Effects Of Type A Botulinum Toxin:an In Vivo Study

BackgroudBotulinum Toxin Type A(BTX-A)is one of seven neurotoxins produced by Clostridium botulinum.BTX-A can results in muscle fiber atrophy and subsequent clinical flaccid paralysis.Consequently,its cosmetic use by subdermal injections in treating wrinkles induced by muscle hyperactivity is widespread.Some physicians have observed a face-lifting effect after intradermal injection of BTX-A to the mid and lower face,however the underlying mechanisms still remain unclear.In 2012,Sang-Ha Oh et al studied the in vitro effects of BTX-A on normal fibroblasts,and found that BTX-A has a significant effect in increasing the level of collagen production and down-regulating its degradation.In 2014,our research group further confirmed the direct anti-photoaging potential of BTX-A in UVB-induced premature senescence of human dermal fibroblasts in vitro through decreasing senescence-related proteins.Whether BTX-A shows its direct skin effects have not been studied in vivo as yet.Part ?The efficacy and safety of fractional CO2 laser combined with topical type A botulinum toxin for facial rejuvenation:A randomized controlled split-face studyMethodsTwenty female subjects were included for this split-face comparative study.One side of each subject's cheek was treated with fractional CO2 plus saline solution,and the other side was treated with fractional CO2 laser plus topically application of BTX-A.Patients received one session of treatment and evaluations were done at baseline,one,four and TEWLve weeks after treatment.The outcome assessments included subjective satisfaction scale;blinded clinical assessment;and the biophysical parameters of roughness,elasticity,skin hydration,transepidermal water loss(TEWL)and the erythema and melanin index.ResultsBTX-A combined with fractional CO2 laser sides showed higher physician's global assessment score,subject satisfaction score,roughness,skin hydration,skin elasticity compared to that of fractional CO2 plus saline solution side at 12 weeks post-treatment.TEWL,erythema,melanin index showed no significantly differences between two sides at baseline,one,four and TEWLve weeks after treatment.ConclusionTopically application of BTX-A could enhance the rejuvenation effect of fractional CO2 laser.Part ?The efficacy of fractional CO2 laser combined with topical type A botulinum toxin for the skin rejuvenation of BALB/c nude miceMethods:Female BALB/c nude mice were divided into following four groups.Ten mice in the first group did not receive any treatment and served as a control.Ten mice in the second group were treated with fractional CO2 plus saline solution.Ten mice in the third group received a topical treatment of BTX-A(1u/cm2)after fractional CO2.Ten mice in the fourth group received a topical application of BTX-A(5u/cm2)followed by fractional CO2.Studies were performed at 4 weeks and 8 weeks after the fractional CO2 After treatment with polyester wax,the skin samples were sliced into 6-mm thicknesses..The sliced sections were treated with haematoxylin and eosin(H&E)and Masson stain.To investigate the levels of senescence-related proteins(COL-1,MMP-1),Immunohistochemical analysis was performed.To investigate the levels of senescence-related mRNA(COL-1,MMP-1),Real-time RT-PCR analysis was performed.ResultsBTX-A promoted fractional CO2-induced dermal thickening,dermal collagen and type I collagen fiber increasing in mouse skin.BTX-A prevented fractional CO2-induced increasing of MMP-1 in dorsal mice skin.ConclusionIn summary,We observed that BTX-A significantly antagonizes senecense in vivo,indicating the potential of BTX-A application for anti-aging treatment.Part ? The efficacy of intradermal injection of type A botulinum toxin forfacial rejuvenation MethodsForty female subjects randomly divided into two groups:BTX-A and controlgroups.In BTX-A group,each subject's facial skin was treated with intradermal injection of BTX-A,and the control group subjects were treated with intradermal saline solution injection.Subjects received one session of treatment and evaluations were done at baseline,four and TEWLve weeks after treatment.The outcome assessments included subjective satisfaction scale;blinded clinical assessment;and the biophysical parameters of roughness,elasticity,skin hydration,transepidermal water loss(TEWL)and the erythema and melanin index.ResultsBTX-A group showed higher physician's global assessment score,subject satisfaction score,roughness,skin hydration,skin elasticity and lower TEWL compared to that of control group at 12 weeks post-treatment.Erythema and melanin index showed no significantly differences between two sides at baseline,four and TEWLve weeks after treatment.ConclusionIn conclusion,intradermal BTX-A injection can be considered as an effective method for facial rejuvenation.