Résumé
Introduction:The rapid expansion of radiofrequency (RF) in telecommunication raises concerns about possible health impacts. Previous studies have shown that radiofrequency exposure at low intensity of 900 MHz (2G) can induce a cold sensation and a thermal preference for warmer environments 1, 2, 3. These results suggest thermoregulatory responses that could trigger the activation of thermogenesis as the browning in white adipose tissue and the implication of TRPM8, an important receptor implicated in the cold sensation [4]. The aim of this study is the evaluation of the impact of 3.5 GHz (5G) RF exposure on UCP1 thermogenic pathway and the interaction between 5G exposure and the TRPM8 cold sensor using TRPM8 knockout (KO) mice.Methods:Adult C57BL/6J, wildtype (WT) and TRPM8 KO female and male mice (n=12) were randomised into 2 subgroups (n=6): 5G group (3.5 GHz), and control group (SHAM). 5G groups (male and female) were exposed twice a day for 7 days at an intensity of 1.5 V/m at 3.5 GHz for one hour. The specific absorption rate (SAR) was calculated at 30 mW/kg. At the end of exposure period, white adipose tissue (WAT) was collected and RT-qPCR was carried out on genes implicated in the thermogenic pathway (UCP-1, PPAR-alpha, PPAR-gamma, PRDM-16, DiO2, S100b, PGC1-alpha, ADRB3, Irisine and Cidea). An analysis of variance test followed by a Mann-Whitney test were used for statistical analysis to evaluate the effects of 3 factors: sex (male vs female), RF exposure (5G vs sham) and genotype (KO vs WT).Results:There is no modification in expression of UCP1, PPAR-alpha, PGC1-alpha, PRDM16, S100b, Di02, ADRB3 and Cidea genes. The 5G exposure increases the expression of Irisine, regardless of the sex and genotype of mice (+75.9%, p=0.002). The expression of PPAR-gamma in female exposed groups increases compared to female sham groups (+51.2%, p=0.03) and compared to male exposed groups (+62.3%, p=0.03). Moreover, the expression of PPAR-gamma is overexpressed in TRPM8 KO exposed groups compared to TRPM8 KO sham groups (+51.8%, p=0.01) and compared to WT exposed groups (+81.2%, p=0.001).Conclusion:Our results show an overexpression of 2 markers (Irisine and PPAR-gamma) implicated in the browning of WAT. This process is currently activated by a cold stimulation to increase the production of heat. Thus, we confirm that RF exposure, particularly 5G signal, induce physiological responses similar to those activated by cold stimulation.