Effects of crude oil and ultraviolet radiation on immunity within mouse skin

Toxicological Effects of Inhaled Crude Oil Vapor

PURPOSE OF REVIEW

The purpose of this review is to assess the toxicological consequences of crude oil vapor (COV) exposure in the workplace through evaluation of the most current epidemiologic and laboratory-based studies in the literature.

RECENT FINDINGS

Crude oil is a naturally occuring mixture of hydrocarbon deposits, inorganic and organic chemical compounds. Workers engaged in upstream processes of oil extraction are exposed to a number of risks and hazards, including getting crude oil on their skin or inhaling crude oil vapor. There have been several reports of workers who died as a result of inhalation of high levels of COV released upon opening thief hatches atop oil storage tanks. Although many investigations into the toxicity of specific hydrocarbons following inhalation during downstream oil processing have been conducted, there is a paucity of information on the potential toxicity of COV exposure itself. This review assesses current knowledge of the toxicological consequences of exposures to COV in the workplace.

Biological effects of inhaled crude oil. VI. Immunotoxicity

Crude oil is an unrefined petroleum product that is a mixture of hydrocarbons and other organic material. Studies on the individual components of crude oil and crude oil exposure itself suggest it has immunomodulatory potential. As investigations of the immunotoxicity of crude oil focus mainly on ingestion and dermal exposure, the effects of whole-body inhalation of 300 ppm crude oil vapor [COV; acute inhalation exposure: (6 h × 1 d); or a 28 d sub-chronic exposure (6 h/d × 4 d/wk. × 4 wks)] was investigated 1, 28, and 90 d post-exposure in Sprague-Dawley rats. Acute exposure increased bronchoalveolar lavage (BAL) fluid cellularity, CD4+ and CD8+ cells, and absolute and percent CDllb+ cells only at 1 d post-exposure; additionally, NK cell activity was suppressed. Sub-chronic exposure resulted in a decreased frequency of CD4+ T-cells at 1 d post-exposure and an increased number and frequency of B-cells at 28 d post-exposure in the lung-associated lymph nodes. A significant increase in the number and frequency of B-cells was observed in the spleen at 1 d post-exposure; however, NK cell activity was suppressed at this time point. No effect on cellularity was identified in the BALF. No change in the IgM response to sheep red blood cells was observed. The findings indicate that crude oil inhalation exposure resulted in alterations in cellularity of phenotypic subsets that may impair immune function in rats.

The effect of exposure to crude oil on the immune system. Health implications for people living near oil exploration activities

People who reside near oil exploration activities may be exposed to toxins from gas flares or oil spills. The impact of such exposures on the human immune system has not been fully investigated. In this review, research investigating the effects of crude oil on the immune system is evaluated. The aim was to obtain a greater understanding of the possible immunological impact of living near oil exploration activities. In animals, the effect of exposure to crude oil on the immune system depends on the species, dose, exposure route, and type of oil. Important observations included; hematological changes resulting in anemia and alterations in white blood cell numbers, lymph node and splenic atrophy, genotoxicity in immune cells, modulation of cytokine gene expression and increased susceptibility to infectious diseases. In humans, there are reports that exposure to crude oil can increase the risk of developing certain types of cancer and cause immunomodulation.Abbreviations: A1AT: alpha-1 antitrypsin; ACH₅₀: hemolytic activity of the alternative pathway; AHR: aryl hydrocarbon receptor; BALF: bronchoalveolar lavage fluid; COPD: chronic obstructive pulmonary disease; CYP: cytochrome P450; DNFB: 2, 4-dinitro-1-fluorobenzene; G-CSF: granulocyte-colony stimulating factor; IFN: interferon; IL: interleukin; 8-IP: 8-isoprostane; ISG15: interferon stimulated gene; LPO: lipid peroxidation; LTB₄: leukotriene B₄; M-CSF: macrophage-colony stimulating factor; MMC: melanomacrophage center; MPV: mean platelet volume; NK: natural killer; OSPM: oil sail particulate matter; PAH: polycyclic aromatic hydrocarbon; PBMC: peripheral blood mononuclear cell; PCV: packed cell volume; RBC: red blood cell; ROS: reactive oxygen species; RR: relative risk; T_H: T helper; TNF: tumour necrosis factor; UV: ultraviolet; VNNV: Viral Nervous Necrosis Virus; WBC: white blood cell.

An animal model and new photosensitizers for photopheresis

Recently, photopheresis was introduced as a therapy for several T cell-mediated disorders. The treatment results in a specific immune response against the pathogenic clone of T cells involved. However, although promising there is controversy concerning the use of photopheresis in some diseases, e.g. systemic sclerosis. One of the problems is that there is not yet sufficient insight into the mechanism underlying the therapy. This lack of knowledge is partly caused by the fact that there are no easy-to-handle animal models available for photopheresis. This report describes such a model--a Wistar-derived rat with contact hypersensitivity (CHS); a T cell-mediated immune response. White blood cells from CHS rats were simultaneously exposed to 8-methoxypsoralen (8-MOP) and ultraviolet A radiation (UVA) and subsequently intravenously injected into other syngeneic rats suffering from the same disorder. This treatment appears to be very efficacious in suppressing the immunological response against the applied contact allergen, 2,4-dinitrofluorobenzene (DNFB). In addition, the generated suppression of CHS is highly specific and transferable. Furthermore, drugs other than 8-MOP (chlordiazepoxide, nitrofurantoin and chlorpromazine) also appear to be active in our model.

An animal model for extracorporeal photochemotherapy based on contact hypersensitivity

Recently, photopheresis was introduced as a specific immune suppressor in several T cell mediated disorders. In order to study photopheresis, animal models are indispensable. This report describes an easy to handle model for this purpose. It concerns the Wistar-derived rat with contact hypersensitivity (CHS), also a T cell mediated disorder that has already been studied extensively in several other fields of research. After subsequent exposure to 8-methoxypsoralen (8-MOP) and ultraviolet A radiation (UVA), white blood cells from CHS rats were intravenously injected into other syngeneic rats suffering from the same disorder. This treatment appears to be very efficacious in suppressing the immunological response against the applied contact allergen, 2,4-dinitrofluorobenzene (DNFB). Cells subsequently exposed to UVA and 8-MOP did not have any effect.

Effects of petrochemicals and ultraviolet radiation on epidermal IA expression in vitro

We previously demonstrated that combined treatment of mice with crude oil and longwave ultraviolet radiation (UVA) led to the depletion of IA-positive cells from the epidermis. In the present study, we have developed an in vitro screening assay for combined effects of purified petrochemicals and UVA on epidermal IA and Thy-1 expression. This method involves removal of skin from donor mice prior to treatment with chemicals and UVA (20,000 J/m2), followed by in vitro culture and subsequent immunoperoxidase staining. In this study, a complete correlation was observed in terms of IA-positive cell density among similarly treated cultured skin and live mice. In vivo and in vitro studies both indicated that anthracene but not phenanthrene or benzo[a]pyrene led to significant depletion of both epidermal Langerhans cells and Thy-1-positive dendritic cells when followed by UVA treatment. The in vitro assay developed for this study should prove to be a valuable tool for the screening of a wide variety of chemicals for contact photosensitizing activity.