Cutaneous Toxicity of Gasoline as an Environmental Pollutant on Mice Skin: Histological and Ultrastrucural Studies

The present investigation was undertaken to determine whether gasoline with different octane number (90 and 80) exposure in healthy Swiss albino mice might affect the skin, in order to declare more recognition on the adverse changes that might occur as a result of exposure to this pollutant. Sixty Swiss albino mice were used and divided into 3 subgroups : control-subgroup, topically treated -subgroup with gasoline 90 and topically treated -subgroup with gasoline 80, both groups two and three treated with (0.5ml/kg B.W.) for 8 weeks.Determination of benzene concentration and some heavy metals in both types of gasoline (90 and 80), determination of some heavy metals bioaccumulation in skin after exposure to both types of gasoline (90 and 80),light and electron microscopical studies were performed.It was found that gasoline 80 contained more concentrations of benzene, lead , cadmium and nickel than gasoline 90. The accumulation of lead, cadmium and nickel in the skin have the following order lead > cadmium > nickel. The light microscopical examinations showed dermatitis such as epidermal hyperplasia, micro abscesses, hyperkeratosis and destruction of the dermis depending upon treatment duration from 4 to 8 weeks. After 8 weeks of topically treated mice with both gasoline type , the scanning electron microscope examination showed scales covering the mice skin and the transition electron microscope showed cytoplasmic vacuoles and mitochondrial degeneration in keratinocytes of all epidermal layers of the mice skin . Moreover, the spinosum keratinocytes of mice skin topically treated with gasoline 80 for 8 weeks had pyknotic nuclei,in addition to expansion of intercellular spaces in the stratum corneum

Cutaneous Toxicity of Gasoline as an Environmental Pollutant on Mice Skin: Histological and Ultrastrucural Studies

The present investigation was undertaken to determine whether gasoline with different octane number (90 and 80) exposure in healthy Swiss albino mice might affect the skin, in order to declare more recognition on the adverse changes that might occur as a result of exposure to this pollutant. Sixty Swiss albino mice were used and divided into 3 subgroups : control-subgroup, topically treated -subgroup with gasoline 90 and topically treated -subgroup with gasoline 80, both groups two and three treated with (0.5ml/kg B.W.) for 8 weeks.Determination of benzene concentration and some heavy metals in both types of gasoline (90 and 80), determination of some heavy metals bioaccumulation in skin after exposure to both types of gasoline (90 and 80),light and electron microscopical studies were performed.It was found that gasoline 80 contained more concentrations of benzene, lead , cadmium and nickel than gasoline 90. The accumulation of lead, cadmium and nickel in the skin have the following order lead > cadmium > nickel. The light microscopical examinations showed dermatitis such as epidermal hyperplasia, micro abscesses, hyperkeratosis and destruction of the dermis depending upon treatment duration from 4 to 8 weeks. After 8 weeks of topically treated mice with both gasoline type , the scanning electron microscope examination showed scales covering the mice skin and the transition electron microscope showed cytoplasmic vacuoles and mitochondrial degeneration in keratinocytes of all epidermal layers of the mice skin . Moreover, the spinosum keratinocytes of mice skin topically treated with gasoline 80 for 8 weeks had pyknotic nuclei,in addition to expansion of intercellular spaces in the stratum corneum

Biological factors controlling developmental duration, growth and metamorphosis of the larval green toad, Bufo viridis viridis

The present study in a controlled laboratory setting provided important insights into both the degree of plasticity and the proximal environmental cues operating in the response of green toad tadpoles to pond drying, food level. It was concluded that timing of metamorphosis and size at metamorphosis were highly affected by pond duration. The effects of pond desiccation are reflected by shorter developmental duration and smaller size at metamorphosis as a result of increased crowding in the shallow tanks than tadpoles in the deep tanks. Bufo viridis raised on high food supplements grew faster than those raised on low food in low or high population density. In the tanks with decreased water and food levels, the tadpoles accelerate development and metamorphose earlier than tadpoles in higher food and water levels. The obtained data revealed that tadpoles grew faster under conditions of high population density than low one in either high or low food levels. Actual density had limited but significant effects on tadpole size and development. It also suggested that density regulation, acting on the tadpole stage, may be present in the population but was of less short-term importance than abiotic factors. Environmentally induced variation in developmental rates translated to changes in relative hind leg length. Hind leg length plasticity was positively correlated with growth rate plasticity. Finally, documenting the recent results of this study, B. viridis breed in temporary ponds and exhibited plasticity in developmental duration and growth rate in response to a change in water level