Sphingosine may have cytotoxic effects via apoptosis on the growth of keloid fibroblasts

Keloids are often resistant to treatment, causing much suffering to the patient. Our previous work found that ceramide (Cer) inhibits growth of fibroblasts via apoptosis. However, when compared to normal fibroblasts (NFs), which are quiescent, keloid fibroblasts (KFs) rapidly proliferate and are reported to be resistant to apoptosis via Cer. Sphingosine (Sph) is a metabolite product of ceramide that has some different biochemical properties. Thereofore, we investigated the cytotoxic effects of Sph on cultured fibroblasts from keloid lesions and normal skin in order to evaluate the possibility of using Sph in the treatment of keloid. We used the lactic dehydrogenase (LDH) method, MTT method, and propidium iodide (PI) method. Sph had cytotoxic effects via apoptosis on both the KFs and NFs. Our results indicate that Sph may be applicable to the future treatment of keloid.