Human sebocyte-based assay system for the screening of compounds to lower the lipid synthesis in sebaceous gland

SZ95 cell is an immortalized human sebaceous gland cell line that shows the morphologic, phenotypic and functional characteristics of normal human sebocytes. Sebocytes may play crucial parts in the pathophysiologic processes and disorders of the pilosebaceous unit. The secretory activity of the sebaceous gland is remarkably species-specific and acne is an exclusively human disease. Thus, this SZ95 cells offer possibilities for investigations on the physiology of the sebaceous gland and its role in sebum-associated skin disease such as acne. In this study, we investigated the effects of 13-cis-retinoic acid (13-cis-RA) and spironolactone, frequently used as therapeutic agents of acne, on the lipid synthesis and proliferation of human sebocytes. Cell proliferation was determined by MTT assay and cytoplasmic lipid droplets was shown by Oil-red a staining. Total lipid levels were biochemically estimated by the sulfo-phospho-vanilline reagent. 13-cis-RA and spironolactone significantly inhibited proliferation and lipid levels in a dose-dependent manner. Combined treatment with testosterone and 13-cis-RA or spironolactone resulted in a lower total lipid levels than that with androgen alone. These observations indicate that 13-cis-RA and spironolactone are potent inhibitors of both cell proliferation and lipid synthesis in human sebocytes. We will provide experimental evidence that this human sebocyte cell line serves as an adequate tool for evaluating the anti-lipogenic activity of various compounds potentially useful for the bioactive cosmeceutical ingredients on acne skin, and studying the intracellular biochemical markers depending on the types of compounds from various sources.