Performance of bat-derived macrophages at different temperatures

Heterothermy, as a temperature-dependent physiological continuum, may affect host-pathogen interactions through modulation of immune responses. Here, we evaluated proliferation and functional performance of a macrophage cell line established from the greater mouse-eared (Myotis myotis) bat at 8, 17.5, and 37°C to simulate body temperatures during hibernation, daily torpor and euthermia. Macrophages were also frozen to -20°C and then examined for their ability to proliferate in the immediate post-thaw period. We show that bat macrophages can proliferate at lower temperatures, though their growth rate is significantly slower than at 37°C. The cells differed in their shape, size and ability to attach to the plate surface at both lower temperatures, being spheroidal and free in suspension at 8°C and epithelial-like, spindle-shaped and/or spheroidal at 17.5°C. While phagocytosis at temperatures of 8 and 17.5°C amounted to 85.8 and 83.1% of the activity observed at 37°C, respectively, full phagocytic activity was restored within minutes of translocation into a higher temperature. Bat-derived macrophages were also able to withstand temperatures of -20°C in a cryoprotectant-free cultivation medium and, in the immediate post-thaw period, became viable and were able to proliferate. Our in vitro data enhance understanding of macrophage biology.

Torpor/hibernation cycle may enhance the risk of insecticides for bats: an in vitro study

Exposure to pollutants is considered one of the potential reasons of population declines in bats. In the context of previous studies, we managed to create and keep a wide collection of cell lines from European bat species. Liver cells were chosen for testing, as they represent the preferred model for toxicological studies. Bats are protected, cell lines replacing experimental animals thus represent a unique opportunity to examine effects of pollutants which animals are exposed to in their environments. Moreover, cell incubation temperature variation may simulate physiological states of heterothermic bats. Liver cell lines were cultivated to the required cell number. Exposure to five different concentrations of permethrin (PM) and imidacloprid (IMI) were used to determine cytotoxic effects of these pesticides on Nyctalus noctula-derived liver cells cultivated at 37 °C and 8 °C for 24 h. An assay based on the measurement of activity of lactate dehydrogenase released from damaged cells was used for quantitating cytotoxicity. Cytotoxicity of IMI ranged from 0% to 47% and from 56% to 67% at 37 °C and 8 °C, respectively. Cytotoxicity of PM ranged from 36% to 56% and from 43% to 88% at 37 °C and 8 °C, respectively. Permethrin was tested on the cells at an order of magnitude lower concentrations; even so, higher degree of cytotoxicity was recorded. Imidacloprid was more toxic to bat liver cells at a hibernation temperature than at body temperature of 37 °C.

Reproductive toxicity of heavy metals in fallow deer in vitro

Sertoli cells play a crucial role in male fertility through boosting and regulating the differentiation of spermatogonial stem cells into mature sperm during spermatogenesis. Female ovarian follicles are responsible for the production of mature ova and control of ovarian steroidogenesis. Disruption of these structures through exposure to environmental pollutants is critical for reproductive health. Here, we derived primary cell cultures of Sertoli cells and ovarian follicles from fallow deer (Dama dama). Cells were used as in vitro models to explore reproductive toxicity of heavy metals in wild species. Adverse effects of cadmium (CdCl2), methylmercury (MeHgCl2), and lead (PbCl2) were investigated through a range of equal molar concentrations (0, 15, 30, 60, 125, 250 µM). We found both concentration-dependent and independent cytotoxic patterns (P < 0.01, P < 0.05) in cells exposed to CdCl2, MeHgCl2, and PbCl2. Based on generation of lipid hydroperoxides, significant levels of cell oxidative perturbation were detected in the CdCl2 (P = 0.0001), PbCl2 (P = 0.001), and MeHgCl2 (P = 0.003) groups. Likewise, the antioxidant enzymes catalase and glutathione peroxidase were inhibited in all metal-treated groups (P < 0.01). Genotoxic DNA damage (single-strand break) was also observed (MeHgCl2 group, P = 0.002; CdCl2 and PbCl2 groups, P = 0.004). Increased activity of superoxide dismutase (P = 0.0002 and P = 0.01) was observed in MeHgCl2 and CdCl2, respectively. Cell apoptosis was detected in all the PbCl2 and CdCl2 (P = 0.00007) and MeHgCl2 (P = 0.001) groups. The results of this study can be used to characterize the responsiveness of fallow deer gonadal cells to the stress of toxic metal exposure.

Diclofenac-induced cytotoxicity in cultured carp leukocytes

Diclofenac is a drug commonly used in human and veterinary medicine for the treatment of diseases associated with inflammation and pain. Medicinal products enter waste and surface waters on an everyday basis and contaminate the aquatic environment. Fish are therefore permanently exposed to these chemicals dissolved in their aquatic environment. To simulate variable environmental conditions, the aim of our study was to examine adverse effects of diclofenac under different temperatures of cell incubation (18, 21, 24, 27 and 30 °C). Cyto-toxic and -static effects of diclofenac in concentrations of 0.001 mcg/ml, 0.01 microg/ml, 0.1 mcg/ml, 1 mcg/ml, 10 mcg/ml and 100 mcg/ml for the carp (Cyprinuscarpio) cultured leukocytes were quantified using detection of lactate dehydrogenase released from damaged cells. Overall DCF cytotoxicity was relatively low and its impact was pronounced at higher temperature and DCF concentration. Cells growth inhibition is changing more rapidly but it is high mainly at the highest concentration from low temperature. DNA fragmentation was not detected in tested leukocyte cell line. CYP450 increased diclofenac cytotoxicity only at the highest concentration but at incubation temperatures 18 and 27 °C. Leukocyte viability is essential for immune functions and any change can lead to reduction of resistance against pathogens, mainly in cold year seasons, when the immune system is naturally suppressed.