Recognizing and sharing emotions are essential for species survival, but in some cases, living with a conspecific in distress condition may induce negative emotional states through empathy-like processes. Studies have reported that stressors promote psychiatric disorders in both, those who suffer directly and who witness these aversive episodes, principally whether social proximity is involved. However, the mechanisms underlying the harmful outcomes of emotional contagion need more studies, mainly in the drug addiction-related behaviors. Here, we investigated the relevance of familiarity and the effects of cohabitation with a partner submitted to chronic stress in the anxiety-like, locomotor sensitization, and consolation behaviors. Male Swiss mice were housed in pairs during different periods to test the establishment of familiarity and the stress-induced anxiety behavior in the elevated plus maze. Another cohort was housed with a conspecific subjected to repeated restraint stress (1 h/day) for 14 days. During chronic restraint the allogrooming was measured and after the stress period mice were tested in the open field for evaluation of anxiety and locomotor cross-sensitization induced by methamphetamine. We found that familiarity was established after 14 days of cohabitation and the anxiogenic behavior appeared after 14 days of stress. Repeated restraint stress also increased anxiety in the open field test and induced locomotor cross-sensitization in the stressed mice and their cagemates. Cagemates also exhibited an increase in the consolation behavior after stress sessions when compared to control mice. These results indicate that changes in drug abuse-related, consolation, and affective behaviors may be precipitated through emotional contagion in familiar conspecifics.

The development of biomaterials substitutes and/or equivalents to mimic normal tissue is a currently challenge in tissue engineering. Studies using cell monolayer culture presents limitations with respect to two-dimensional interactions between the cells, and experiments using animals cannot predict results in humans, due to the high viability, thus compromising their clinical relevance. In consequence, threedimensional cell culture (3D) using a biomaterial designed to promote cell proliferation and differentiation has been used to recreate the complexity of a normal tissue, allowing a larger and complex cellular interaction. Aiming to mimic the in vivo environment, the present work refers to create a reconstituted dermis (dermal equivalent) in vitro using collagen, the most abundant component of the dermis, as biological matrix, as support for human fibroblasts, as well evaluate the photobiomodulation with light at 630 nm. First, a sponge was prepared from serous 1.1% porcine collagen hydrolyzed for 96 h. The biomaterial was characterized by determination of its porosity, pore diameter, the fluid absorption and the biocompatibility assays, since these parameters are important to the cell proliferation and differentiation resulting in the in vitro tissue formation. The biomaterial showed porosity of 95.2%, with a median pore of 44 µM estimated by mercury porosimetry injection, and channels with an average distance between the walls of 7814 µM estimated by SEM. These values are considered as ideal for a biosupport fibroblast growth. The absorption of water and growth medium was 95%, and the sponge showed no cytotoxicity for the Vero cell line. Additionally, it was investigated the effect of irradiation in 3D culture with red light (dose 30 J cm-2), that showed photobiomodulation on the dose 30 J cm-2 , for culturing cells in monolayer and in the early-stage of the cell growth in three-dimensional culture. By confocal microscopy, it was verified that the cells cultured in the presence of the sponge (3D culture), allows differentiation and extracellular matrix secretion. Therefore, the results showed that the collagen sponge used as a biomaterial for cell support and the photobiomodulation at 630 nm and dose of 30 J cm-2 are efficient for the production of a reconstructed dermis (equivalent) in vitro.

Recognize and share emotions are essential for species survival, but in some cases, living with a conspecific in distress condition may induce negative emotional states through empathy-like processes. Studies have reported that stressors promote psychiatric disorders in both, who suffers directly and who witness these aversive episodes, principally whether social proximity is involved. However, the mechanisms underlying the harmful outcomes of emotional contagion needs more studies, mainly in the drug addiction-related behaviors. Here, we investigated the relevance of familiarity and the effects of cohabitation with a partner submitted to chronic stress in the anxiety-like, locomotor sensitization and consolation behaviors. Male swiss mice were housed in pairs during different periods to test the establishment of familiarity and the stress-induced anxiety behavior in the elevated plus maze. Another cohort was housed with a conspecific subjected to repeated restraint stress (1h/day) for 14 days. During chronic restraint the allogrooming was measured and after the stress period mice were tested in the open field for evaluation of anxiety and locomotor cross-sensitization induced by methamphetamine. We found that familiarity was established after 14 days of cohabitation and the anxiogenic behavior appeared after 14 days of stress. Repeated restraint stress also increased anxiety in the open field test and induced locomotor cross-sensitization in the stressed mice and their cagemates. Cagemates also exhibited increase in consolation behavior after stress sessions when compared to control mice. These results indicate that changes in drug abuse-related, consolation and affective behaviors may be precipitate through emotional contagion in familiar conspecifics.