The pesticide adjuvant, Toximul, alters hepatic metabolism through effects on downstream targets of PPARalpha.

Previous studies demonstrated that chronic dermal exposure to the pesticide adjuvant (surfactant), Toximul (Tox), has significant detrimental effects on hepatic lipid metabolism. This study demonstrated that young mice dermally exposed to Tox for 12 days have significant increases in expression of peroxisomal acyl-CoA oxidase (mRNA and protein), bifunctional enzyme (mRNA) and thiolase (mRNA), as well as the P450 oxidizing enzymes Cyp4A10 and Cyp4A14 (mRNA and protein). Tox produced a similar pattern of increases in wild type adult female mice but did not induce these responses in PPARalpha-null mice. These data support the hypothesis that Tox, a heterogeneous blend of nonionic and anionic surfactants, modulates hepatic metabolism at least in part through activation of PPARalpha. Notably, all three groups of Tox-treated mice had increased relative liver weights due to significant accumulation of lipid. This could be endogenous in nature and/or a component(s) of Tox or a metabolite thereof. The ability of Tox and other hydrocarbon pollutants to induce fatty liver despite being PPARalpha agonists indicates a novel consequence of exposure to this class of chemicals, and may provide a new understanding of fatty liver in populations with industrial exposure.

Molecular pathological analysis for determining the possible mechanism of piperonyl butoxide-induced hepatocarcinogenesis in mice.

Piperonyl butoxide (PBO), alpha-[2-(2-butoxyethoxy)ethoxy]-4,5-methylene-dioxy-2-propyltoluene, is widely used as a synergist for pyrethrins. In order to clarify the possible mechanism of non-genotoxic hepatocarcinogenesis induced by PBO, molecular pathological analyses consisting of low-density microarray analysis and real-time reverse transcriptase (RT)-PCR were performed in male ICR mice fed a basal powdered diet containing 6000 or 0 ppm PBO for 1, 4, or 8 weeks. The animals were sacrificed at weeks 1, 4, and 8, and the livers were histopathologically examined and analyzed for gene expression using the microarray at weeks 1 and 4 followed by real-time RT-PCR at each time point. Reactive oxygen species (ROS) products were also measured using liver microsomes. At each time point, the hepatocytes of PBO-treated mice showed centrilobular hypertrophy and increased lipofuscin deposition in Schmorl staining. The ROS products were significantly increased in the liver microsomes of PBO-treated mice. In the microarray analysis, the expression of oxidative and metabolic stress-related genes--cytochrome P450 (Cyp) 1A1, Cyp2A5 (week 1 only), Cyp2B9, Cyp2B10, and NADPH-cytochrome P450 oxidoreductase (Por) was over-expressed in mice given PBO at weeks 1 and 4. Fluctuations of these genes were confirmed by real-time RT-PCR in PBO-treated mice at each time point. In additional real-time RT-PCR, the expression of Cyclin D1 gene, key regulator of cell-cycle progression, and Xrcc5 gene, DNA damage repair-related gene, was significantly increased at each time point and at week 8, respectively. These results suggest the possibility that PBO has the potential to generate ROS via the metabolic pathway and to induce oxidative stress, including oxidative DNA damage, resulting in the induction of hepatocellular tumors in mice.

Effect of herbal molluscicides and their combinations on the reproduction of the snail Lymnaea acuminata.

Effects of sublethal treatment (20 and 60% of LC50/24 h) of the plant-derived molluscicides Annona squamosa Linn. and Lawsonia inermis Linn. and their combinations with other herbal molluscicides, such as Cedrus deodara Roxb, Azadirachta indica A. Juss, bulb powder of Allium sativum Linn. and Polianthes tuberosa Linn., and oleoresin of Zingiber officinale Rosc., and acetogenins extracted from the seeds of A. squamosa Linn., on the reproduction of the snail Lymnaea acuminata have been studied. It was observed that the plant-derived molluscicides singly and in binary combinations with other herbal molluscicides and the extracted acetogenins caused a significant reduction in the fecundity, hatchability, and survival of young snails. Withdrawal of the snails to fresh water after the above treatment caused a significant recovery in the fecundity of the snail Lymnaea acuminata. Twenty-four-hour sublethal treatment with the acetogenins caused a maximum reduction in the protein, amino acid, DNA, and RNA in the ovotestis of treated Lymnaea acuminata.