The effects of ginko biloba on hair growth in mice

Hair loss is a cosmetic problem that almost everyone faces during a period of their life. Although the causes of hair loss are varied, it basically results in hair cycle changes. With this change, the transition from the telogen phase to the anagen phase becomes difficult, the anagen phase becomes shorter and the telogen hair follicle/anagen hair follicle ratio increases. The aim of the hair loss treatment is to reverse this change. Ginkgo biloba (GB) is a living fossil tree with no similar species surviving today. It is widely used in Asian traditional medicine. Clinical use is available for the supportive treatment of Alzheimer's disease, senile dementia, cerebral insufficiency, intermittent claudication and multi-infarct dementia. Mechanisms of action include increased cerebral blood flow, antioxidant effects and anti- inflammatory effects. Factors causing the transition of hair follicle (HF) from anagen phase to telogen phase have been accused of disruption of vasodilatation mechanisms, increased oxidant stress and triggering of inflammatory processes. Based on these findings, we aimed to investigate the effects of GB on HF by topical and systemic application in vivo. In this way, it is aimed to determine whether the substance is safe, positive or negative effects on HF, and other possible effects and side effects. MATERIALS and METHODS A total of 28 Swiss Albino 7-week-old male mice were included in the study. Depilation was applied under anesthesia to 2x4 cm area on the dorsum of all rats. Mice were randomly divided into 4 groups as negative control group where no drugs are administered, positive control group where 2% topical minoxidil is administered, third group where topical GB is administered and last group where oral GB is administered.The mice were started medication given/applied 1 day after depilation and went on for 28 days. HF growth was observed macroscopically throughout the process in topical and systemic product groups compared with other groups. On the 0, 7, 10, 14, 21, 28 days after depilation, the back of the mouse was photographed with a digital camera. After transferring the images to the computer, "Percentage of hair growth = (Hairy area:Depilation area) x100 " formula was evaluated quantitatively by 3 blinded- physicians. On day 28, two 6 mm punch biopsy materials were obtained from each mouse skin under anesthesia. One of the materials was transverse sectioned, the other was longitudinally sectioned, and stained with hematoxylin and eosin. Longitudinal-sectioned samples were used to observe follicle morphology, to classify different stages of HF morphogenesis, and to determine the number of follicles in subcutaneous tissue. Transverse-sectioned samples were used to determine the number of HFs and mean diameter. The mean diameter of HF, anagen hair/telogen hair ratio, subcutaneous follicle count and HF mean length were evaluated by light microscopy. RESULTS After depilation at macroscopic morphological observation positive control group showed more and faster hair growth than the other groups. Also both topical and systemic groups showed more and faster hair growth than the negative group. The percentage of hair growth was much lower in the negative control group than in all other groups. Histopathological analysis on day 28 post-depilation revealed that most of the hairs in the negative control group were in the early anagen phase, characterized by bulbus in dermis and enlarged dermal papillae. In contrast, the other groups were at least anagen stage 3c-4, characterized by the largest volume of bulbus, the thinner dermal papillae, the presence of follicles in the deep subcutis, and the newly developing hair shaft reaching the lower level of the sebaceous gland. In the systemic treatment group, bulbus was deeper and follicles were larger than the topical. In all experimental groups there were more follicles in the subcutaneous tissue compared to the negative control group. The difference was statistically significant (p <0.05). The number of subcutaneous tissue follicles in the systemic GB group was significantly higher than the topical GB group (p <0.05). HF mean diameter was larger in all experimental groups compared to the negative control group. The difference between the other experimental groups and the negative control group was statistically significant (p <0.05). The difference between topical and systemic GB groups was not statistically significant (p> 0.05). HF mean length did not differ significantly between the systemic GB group and the positive control group (p> 0.05). All groups were significantly higher than the negative control group (p <0.05). Anagen hair/telogen hair ratio was significantly higher in systemic GB group and positive control group compared to both topical GB group and negative control group (p <0.05). The difference between systemic GB group and positive control group was not significant (p> 0.05). Also, the difference between topical GB group and negative control group was not significant (p> 0.05). CONCLUSION In our study, histopathological evaluation of Swiss-Albino rats in both topical and systemic groups revealed that there was an increase in the number of follicles in subcutaneous tissue, anagen hair/telogen hair ratio, HF mean diameter and HF mean length parameters compared to negative control group. Macroscopic morphological observation suggested that both topical administration and systemic administration of GB positively affected HF growth.