Expression pattern and intensity of protoporphyrin IX induced by liposomal 5-aminolevulinic acid in rat pilosebaceous unit throughout hair cycle

Abstract

We have developed liposomal formulation of 5-aminolevulinic acid (ALA) to enhance topical delivery and examined ALA-induced protoporpyrin (PpIX) expression in rat pilosebaceous unit throughout hair cycle. Two types of liposomes--glycerol dilaulate (GDL) and phosphatidylcholine (PC)--were formulated and both liposomal ALA increased PpIX expression in rat dorsal skin and pilosebaceous units when compared with free ALA. However, iontophoresis combined with liposomal ALA reduced the expression intensity of PpIX in hair bulbs although it achieved deeper and wider expression of PpIX through transfollicular pathway. After topical application in intact or depilated rat skin, liposomal ALA produced excellent PpIX expression in pilosebaceous units. The expression pattern and intensity of PpIX changed in hair cycle-dependent manner: specific expression only in sebaceous glands was observed at telogen; strong expression in whole pilosebaceous units was shown at anagen with intense expressions in hair bulbs and sebaceous glands; and a pattern similar to anagen but reduced intensity in the hair bulbs was seen at catagen. Throughout hair cycle, the expression pattern and intensity were dramatically changed in hair follicular epithelial cells depending on the cell density and proliferation activity of those cells, whereas those were consistent in sebaceous glands regardless of hair cycle. Little expression was shown in dermis. Photoactivation effect of 20% liposomal ALA-PDT using a red filtered-halogen lamp damaged sebaceous glands, hair follicles and epidermal layers. Formation of a thicker epidermal layer was observed, and hair induction after depilation was inhibited along with damage in sebaceous glands.

Noninvasive and persistent transfollicular drug delivery system using a combination of liposomes and iontophoresis

“…Previously, Han et al also reported that transfollicular delivery of drug molecules was enhanced by using a combination of liposomes and iontophoresis (Han et al, 2005;Han et al, 2004). In those reports, the intrafollicular delivery of small fluorescent drug molecules was investigated.…”

Expression Pattern of Cyclooxygenase-2 in Normal Rat Epidermis and Pilosebaceous Unit during Hair Cycle

“…It was reported that during the first hair cycle of the normal rat skin, the sebaceous glands continually developed in the anagen and attained its fully development at catagen [ 9 ]. This development pattern of sebaceous glands of rat skin was repeated in our study, with the sizes of the sebaceous glands obviously increasing in the transition from anagen to catagen and holding steady in catagen and telogen.…”

Nonpigmented hair removal using photodynamic therapy in animal model

“…A previous study reported that PDT using 5‐aminolevulinic acid (5‐ALA) induced hair follicle damage and inhibited the hair cycle in Sprague–Dawley rats. However, the detailed nature and results of hair damage were not well described . Grossman et al reported in their pilot study that PDT achieved more than 50% hair removal in 11 subjects and persisted for 6 months .…”