Action of 1-(11-selenadodecyl)-glycerol and 1-(11-selenadodecyl)-3-trolox-glycerol against lipid peroxidation

Oxidative stress, hematological and biochemical alterations induced by sub-acute exposure to fipronil (COACH®) in albino mice and ameliorative effect of selenium plus vitamin E

Fipronil (FIP) is a highly effective, broad-use insecticide that belongs to the phenylpyrazole chemical group. It is extensively used in the agriculture and veterinary medicine for controlling a wide variety of pests. Though FIP showed lower toxicity in vertebrates than in insects, it was recognized to have a variety of toxic effects in mammals. The present study was undertaken to evaluate FIP-induced alterations in the blood biochemical markers and oxidative stress parameters in male albino mice via oral sub-acute toxicity exposure. The possible ameliorative effect of the pretreatment with selenium plus α-tocopherol (vitamin E) against the harmful effects of FIP was also investigated. Mice in FIP-test groups were exposed to different sublethal doses, i.e., 1.43, 2.87, and 4.78 mg active ingredient (AI)/kg body weight (b.w.), equal to 1/100, 1/50, and 1/30 LD₅₀ of FIP, respectively, for 28 days. Mice in the amelioration groups were orally administered with selenium + vitamin E (0.3 mg + 22.5 mg/kg b.w., respectively) 14 days prior to exposure to the higher dose (4.78 mg/kg) of FIP for another 14 days. Fipronil exposure at medium and high doses showed lowered values of red blood cell count (RBC), hematocrit (HCT), hemoglobin (HGB), white blood cell (WBC), and platelet (PLT) counts after 28-day exposure, compared to the control. All three doses caused significant increases in levels of liver-function biomarkers, i.e., aspartate amino transaminase (AST), alanine amino transaminase (ALT), alkaline phosphatase (ALP), cholesterol, and bilirubin levels compared to the control. Levels of biomarkers related to kidney functions, i.e., urea, uric acid, and creatinine, increased significantly than these of the control. Likewise, the oxidative stress indices, i.e., hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), significantly increased at the higher and medium doses, while antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD), decreased significantly. On the other hand, prior administration of selenium + vitamin E in the FIP-exposed mice led to restore values of most hematological parameters nearly to these of the control. Also, the levels of AST, total protein, and creatinine seemed to be restored to the control values. Interestingly, pretreatment with selenium + vitamin E restored the levels of antioxidant enzymes, CAT and SOD, to the control values, whereas, oxidative stress indices, H₂O₂ and MDA, remained significantly high. It is our thought that the sublethal dose less than 1.43 mg/kg b.w. of commercial formulation of FIP (COACH^® 200 SC) could be considered as no-observed-adverse-effect-level(NOAEL) under our present experimental conditions at short-term toxicity study. On the other hand, the higher sublethal doses, 4.78 and 2.87 mg/kg b.w., induced significant adverse effects in biomarkers and may be deleterious to human health following long-term exposure.

Mimicking the lipid peroxidation inhibitory activity of phospholipid hydroperoxide glutathione peroxidase (GPx4) by using fatty acid conjugates of a water-soluble selenolane

A series of fatty acid conjugates of trans-3,4-dihydroxy-1-selenolane (DHS) were synthesized by reacting DHS with appropriate acid chlorides. The obtained monoesters were evaluated for their antioxidant capacities by the lipid peroxidation assay using a lecithin/cholesterol liposome as a model system. The observed antioxidant capacities against accumulation of the lipid hydroperoxide (LOOH) increased with increasing the alkyl chain length and became saturated for dodecanoic acid (C₁₂) or higher fatty acid monoesters, for which the capacities were much greater than those of DHS, its tridecanoic acid (C₁₃) diester, and PhSeSePh. On the other hand, the bacteriostatic activity of myristic acid (C₁₄) monoester, evaluated through the colony formation assay using Bacillus subtilis, indicated that it has higher affinity to bacterial cell membranes than parent DHS. Since DHS-fatty acid conjugates would inhibit lipid peroxidation through glutathione peroxidase (GPx)-like 2e⁻ mechanism, higher fatty acid monoesters of DHS can mimic the function of GPx4, which interacts with LOOH to reduce it to harmless alcohol (LOH). Importance of the balance between hydrophilicity and lipophilicity for the design of effective GPx4 mimics was suggested.

Impact of L-carnitine and Selenium Treatment on Testicular Apoptosis in Rats Exposed to 2.45 GHz Microwave Energy

OBJECTIVE

It has been suggested that electromagnetic radiation (EMR) by wireless devices (2.45 GHz) induces testicular apoptosis. We investigated if supplemental selenium (Se) and L-carnitine may reduce this adverse effect.

MATERIAL

Twelve-week old male Wistar albino rats were used in this study. Twenty-four rats were equally divided into four groups which were named as: sham group, EMR-only, EMR+L-carnitine (1.5 mg L-carnitine/kg/day) and EMR+Se (1.5 mg Se/kg/-every other day).

RESULTS

The level of Bcl-2, Bax, caspase-3 and -8 were compared and a significant difference was found between the sham and EMR-only groups (p < 0.05), and Bcl-2, Bax, caspase-3 and -8 expressions increased in the EMR-only group. The level of Bcl-2, Bax, tumour necrosis factor-alpha (TNF-α), caspase-3 and -8 were compared and a significant difference was found between the sham and EMR+L-carnitine groups (p < 0.05) and Bcl-2, Bax, TNF-α, caspase-3 and -8 expressions increased in the EMR+L-carnitine group. The level of Bcl-2, Bax, TNF-α, caspase-3 and -8 were compared and a significant difference was found between the sham and EMR+Se groups (p < 0.05) and Bcl-2, Bax, TNF-α, caspase-3 and -8 expressions increased in the EMR+Se group. When the expression of caspase-8 was compared, a significant difference was found between the EMR-only and EMR+Se groups (p < 0.05). Caspase-8 expression decreased in EMR+Se group compared with EMR-only group.

CONCLUSION

Electromagnetic radiation exposure resulted in testicular apoptosis in rats, mainly by the intrinsic pathways by down-regulated expression of caspase-8. Reduction in the activation of the intrinsic pathway of apoptosis was found higher with selenium administration compared with L-carnitine administration.