Effects of 4-hydroxyphenyl retinamide in different vehicles on the proliferation and apoptosis of human keloid fibroblasts

Abstract

Objective To evaluate effects of 4-hydroxyphenyl retinamide (4-HPR) in different vehicles on the proliferation and apoptosis of human keloid fibroblasts (HKFs) . Methods A film-ultrasonic dispersion method was used to prepare 4-HPR liposome solution and 4-HPR microbubbles. Primary HKFs were in vitro treated with the 4-HPR liposome solution at different concentrations of 0-80 mg/L for 6-48 hours, and the proliferative activity of HKFs was evaluated by methyl thiazolyl tetrazolium (MTT) assay. Some other HKFs were divided into 3 experimental groups to be treated with 15 mg/L 4-HPR solution (4-HPR solution group) , 15 mg/L 4-HPR liposome solution (4-HPR liposome solution group) and 15 mg/L 4-HPR microbubbles (4-HPR microbubble group) , respectively, and each group was divided into ultrasonic-treated and -untreated subgroups. HKFs without treatment served as control group. After 24-hour treatment, MTT assay was conducted to evaluate the proliferative activity of HKFs in the above groups, flow cytometry to detect apoptosis of HKFs in all groups except the 4-HPR solution group. Results The 4-HPR liposome solution and 4-HPR microbubbles were successfully prepared. MTT assay showed inhibitory effects of 4-HPR liposome solution at concentrations of 1-80 mg/L on the proliferation of HKFs, and the proliferation inhibition rate was positively associated with the drug concentrations (r= 0.633, P < 0.01) . After the ultrasonic treatment, inhibitory effects on the proliferation of HKFs significantly differed among the 4-HPR microbubble group, 4-HPR solution group and 4-HPR liposome solution group (P < 0.01) . The 4-HPR liposome solution group and the 4-HPR microbubble group both showed significantly increased apoptosis rates (21.81% ± 3.73%, 39.79% ± 1.61%, respectively) compared with the control group (6.18% ± 0.61%, both P < 0.01) . Conclusion The 4-HPR microbubbles are successfully prepared, and 4-HPR in different vehicles all can promote HKF apoptosis and suppress HKF proliferation, among which, 4-HPR microbubbles in combination with ultrasonic treatment have stronger inhibitory effects than the 4-HPR liposome solution. Key words: Tretinoin; Keloid; Fibroblasts; Cell proliferation; 4-Hydroxyphenyl-retinamide