Widespread calcium deposits, as detected using the alizarin red S technique, in the nervous system of rats treated with dimethyl mercury

Abstract

It has been reported that the alizarin red S technique may be used to visualize both intracellular and extracellular calcium deposits. Using this method histologic observations of the nervous system were made in rats that were given dimethyl mercury at 5 mg/kg per day for 12 consecutive days, and killed on days 1, 4, 7, 10, 12, 24, 32, 49, 100 and 140 (day 0 was the day that the final dose was administered). Neuronal degeneration with calcium deposition was found in the nervous system from day 4 onward. In the cerebellum alizarin red S-positive granules became gradually larger with time after dimethyl mercury administration, and large calcospherites were observed from day 32 onward. In contrast, the visualization of calcium deposits in the cerebral cortex was restricted to days 10-12. Calcium deposits were found in the ascending axons of the dorsal root ganglion neurons (dorsal fascicles of the spinal cord), but not in their perikarya. These findings suggest that widespread calcium deposition could occur in the nervous system following dimethyl mercury exposure, and that in the rat the mechanism of calcium deposition differs depending upon the brain region.

Ultrastructural investigation of microcalcification and the role of oxygen–glucose deprivation in cultured rat hippocampal slices

“…Thus, mineralized cells shared ultrastructural features in both control and OGD-lesioned slices; microcalcification was specifically associated with mitochondria but not other organelles. This novel type of mineralization and cell death are in contrast with a previous in vivo finding that intracellular calcification initially occurs in the mitochondria of degenerating neurons, proceeds to fill the dead cell, and even extends beyond cells Mori et al, 2000;Nitsch and Scotti, 1992;Simon et al, 1984;Sztriha et al, 1985). This may be attributable to the nature of slice cultures because early recognition of cell debris by infiltrating macrophages is absent, thus resulting in the slow progression of degenerative processes during culture.…”

“…We examined the extent and topography of calcification using alizarin red S staining, which is a sensitive and specific method for detecting calcium deposition (Mori et al, 2000;Nitsch and Scotti, 1992), and the osmium/potassium-bichormate method to precipitate and ultrastructurally visualize endogenous calcium (Probst, 1986). Finally, we employed field emission-transmission electron microscopy (FE-TEM) equipped with EDAX (Energy Dispersive X-ray Analysis)…”

Effects of dietary methylmercury on the zebrafish brain: histological, mitochondrial, and gene transcription analyses

“…Intracellular accumulation of Ca 2? was also observed in rats treated with dimethylmercury by injection at 5 mg/kg/day for 12 days (Mori et al 2000). Ca 2?…”

Spatiotemporal expression of osteopontin in the striatum of rats subjected to the mitochondrial toxin 3-nitropropionic acid correlates with microcalcification

“…This spatiotemporal progression of calcification after ischaemic insult appears to be very closely comparable to the OPN expression pattern observed in our study. In addition, several lines of inquiry have revealed that intracellular calcification initially occurs in the mitochondria of degenerating neurons and subsequently propagates throughout the whole cell after brain insults54555657. What leads to intramitochondrial OPN expression is not certain, but it can be inferred that OPN is initially localised in degenerating mitochondria where initial intracellular calcification occurs, and then accumulates in the periphery of the degenerating neurites from where calcification subsequently spreads to the entire dendroplasm.…”