Harmful effects of formaldehyde and possible protective effect of Nigella sativa on the trachea of rats

Objective: We aimed in this study to investigate the harmful effects of formaldehyde (FA) inhalation and possible protective effects of Nigella sativa (NS) on rats’ trachea.Materials and Methods: In this study, 63 adult male rats were used. Animals were divided into nine groups. Group I was used as control group. All other groups were exposed to FA inhalation. Group III, V, VII, and IX were administered NS by gavage. Tissues were examined histologically, and immunohistochemical examination for Bax and caspase‑3 immunoreactivity was carried out. Results: Our study demonstrated that FA caused apoptosis in the tracheal epithelial cells. The most apoptotic activity occurred at a 10 ppm dose in a 13‑week exposure. Distortion of tracheal epithelium and cilia loss on epithelial surface was present in all groups. However, NS treated Groups VII and IX had decreased apoptotic activity and lymphoid infiltration and protected the epithelial structure, despite some shedded areas. Difference of tracheal epithelial thickness and histological score was statistically significant between Group VI–VII and VIII–IX.Conclusion: FA induces apoptosis and tracheal epithelial damage in rats, and chronic administration of NS can be used to prevent FA‑induced apoptosis and epithelial damage.Keywords: Apoptosis, formaldehyde, Nigella sativa, rat, trache

Presence of the diatom genus Pseudo-nitzschia

The potentially toxic diatom genus Pseudo-nitzschia and particulate domoic acid (pDA) concentrations were investigated weekly to bi-weekly from October 2013 to September 2014 in the Golden Horn Estuary. Pseudo-nitzschia species were detected in 324 of the 666 samples (approximate to 49%). Two species, Pseudo-nitzschia calliantha and Pseudo-nitzschia pungens, were identified based on the scanning electron microscopy examination. A bloom of P. calliantha occurred between May and June, average cell density, 1.1x10(6) cellsL(-1) in May. Pseudo-nitzschia calliantha was commoner than P. pungens almost throughout the study period. They occurred over a wide temperature range (7.4-26.3 degrees C) and moderate salinity (5.9-19.9). The highest cell density occurred at 14.7-19.6 degrees C and 18.5-19.0 salinity, in the lower and middle estuary in winter and late spring. Pseudo-nitzschia species were found in very low densities in the upper estuary, which has variable salinity and low light availability due to high concentrations of suspended material. The pDA concentration in seawater was 0.03-1.0 mu gL(-1). The distribution pattern of pDA coincided with the presence of Pseudo-nitzschia. Pseudo-nitzschia abundance was low in October, when pDA was highest. There was a highly positive correlation between Pseudo-nitzschia abundance and salinity/Secchi depth/pH (p.001), but a negative correlation with inorganic nutrients and Si:N (p<.001). pDA was positively correlated with temperature/salinity and Secchi depth, but negatively correlated with inorganic nutrients (p<.001). Low light availability and highly variable salinity may limit the growth of Pseudo-nitzschia in the upper estuary and the presence of pDA throughout the study area may be related to transport by particulate matter