Effect of High-Dose Topical Minoxidil on Erythrocyte Quality in SKH1 Hairless Mice

Toxicological assessment of minoxidil: A drug with therapeutic potential besides alopecia

Minoxidil is regularly prescribed for alopecia, and its therapeutic potential has expanded in recent times. However, few studies have been conducted to evaluate its toxicity, and controversial findings regarding its mutagenic activities remain unsolved. This study aimed to access cytotoxic, genotoxic, and mutagenic properties of minoxidil using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay, comet assay, and micronucleus test in mouse fibroblast (L929) cells and its point mutation induction potential in the Salmonella/microsome assay. Furthermore, an in vivo toxicity assessment was conducted in Caenorhabditis elegans. Minoxidil showed cytotoxicity at 2.0 mg/mL in MTT assay. Genotoxicity was observed after 3 h treatment in L929 cells using comet assay. No mutagenic effect was observed in both the micronucleus test and the Salmonella/microsome assay. The lethal dose 50 in C. elegans was determined to be 1.75 mg/mL, and a delay in body development was detected at all concentrations. In conclusion, minoxidil induces DNA damage only in early treatment, implying that this DNA damage may be repairable. This observation corroborates the absence of mutagenic activities observed in L929 cells and Salmonella typhimurium strains. However, the toxicity of minoxidil was evident in both C. elegans and L929 cells, underscoring the need for caution in its use.

Evaluation of the efficacy and toxicity of oral and topical pumpkin oil on the hair growth of mice

This study aimed to evaluate the efficacy and safety of a topical and oral administration of pumpkin seed oil (PSO) on the hair growth of BALB/c male mice. The animals had their dorsal area shaved (2 ×2 cm) and they were divided into 6 experimental groups. They received orally saline (OS), finasteride (F), or PSO (OP) for 14 days; or topically saline (TS), minoxidil (M), or PSO (TP) for 7 days. The euthanasia of all of the mice occurred on the 22nd day, and the histological slides from the skin area were analyzed. Lipoperoxidation in the liver was assessed through the TBARS method and was also evaluated by the antioxidant enzymes (SOD and CAT). The comet assay and the micronucleus tests were performed for genotoxic/mutagenic safety analyses. A significant increase in the number of hair follicles in the TP group was seen (8.8 ± 0.8) but it was disorganized, with loose dermal collagen. Finasteride presented a significant increase in the levels of the TBARS, SOD, and CAT in the liver, and M increased the DNA damage in the blood and the liver tissues. PSO did not induce any significant changes. In addition, PSO did not induce genotoxic or mutagenic effects. In conclusion, the oral PSO for 14 days acted in the proliferation of the hair follicles, without toxicity signals in the liver. DATA AVAILABILITY: The authors confirm that all of the relevant data is included in the article and/or in the supplementary information file.