Effects of high-fat diets rich in either omega-3 or omega-6 fatty acids on UVB-induced skin carcinogenesis in SKH-1 mice.

Our previous studies reported that caffeine or voluntary exercise decreased skin tumor multiplicity, in part, by decreasing fat levels in the dermis. These data suggest that tissue fat may play an important role in regulating ultraviolet light (UV) B-induced skin tumor development. In the present study, we explored the effects of high-fat diets rich in either omega-3 or omega-6 fatty acids on UVB-induced skin carcinogenesis. SKH-1 mice were irradiated with 30 mJ/cm(2) of UVB once a day, two times per week for 39 weeks. During UVB treatment, one group of mice was given a high-fat fish oil (HFFO) diet rich in omega-3 fatty acids and the other group of mice was given a high-fat mixed-lipids (HFMLs) diet rich in omega-6 fatty acids. The results showed that, compared with HFML diet, HFFO treatment (i) increased latency for the development of UVB-induced skin tumors; (ii) decreased the formation of papilloma, keratoacanthoma and carcinoma by 64, 52 and 46%, respectively and (iii) decreased the size of papilloma, keratoacanthoma and carcinoma by 98, 80 and 83%, respectively. Mechanistic studies with antibody array revealed that compared with HFML diet, administration of HFFO to the mice significantly decreased the UVB-induced increases in the levels of TIMP-1, LIX and sTNF R1 as well as other several proinflammatory cytokines and stimulated the UVB-induced apoptosis in the epidermis. Our results indicate that omega-3 fatty acids in HFFO diet have beneficial effects against UVB-induced skin carcinogenesis, and these effects may be associated with an inhibition on UVB-induced inflammatory response.

Differential development of central dopaminergic and serotonergic systems in BALB/c and C57BL/6J mice.

Although the etiology of autism is unclear, disruptions of the dopaminergic and serotonergic systems have been associated with the disorder. Based on behavioral differences observed in the BALB/c strain of mice in comparison to other strains, notably, C57BL/6J mice, it has been suggested that the BALB/c strain may serve as an animal model of autism. However, to date, most work investigating neural and behavioral abnormalities in this strain has been performed in adult animals. Therefore, the present study was conducted to examine the development of the central dopaminergic and serotonergic systems of BALB/c mice as compared to C57BL/6J mice. Levels of dopamine, serotonin, and their metabolites in several different brain regions and at three ages during development were measured. Alterations in both monoaminergic systems associated with age and strain were detected across brain regions indicating that there are neurochemical differences between these strains early in life. However, despite these differences in the development of brain monoaminergic systems, it remains difficult to declare this strain as a valid model of autism.