Parkinson’s disease (PD) is a progressive neurological disorder marked by nigrostriatal dopaminergic degeneration. dopaminergic neuronal cell degeneration. Quality histochemical (TUNEL or activated caspase-3 staining) or ultrastructural (electron microscopy) features of apoptotic cell death were present in the striatal neuronal cell after chronic rotenone intoxication. We conclude that chronic rotenone intoxication may enhance oxidative and nitrosative stress that induces mitochondrial dysfunction and ultrastructural damage resulting in translocation of Bim and Bax from cytosol to mitochondria that contributes to apoptotic cell death in the striatum via cytochrome c/caspase-3 signaling cascade. relative to β-actin protein detected in the cytosolic or relative to cytochrome c oxidase subunit IV (COX-IV) in the mitochondrial fraction of samples collected from … 2.4 Neurons with Ultrastructural Features of Apoptosis and Mitochondria Damage in MLN518 the Striatum Following Chronic Rotenone Intoxication Our third series of experiments determined whether the integrity of the mitochondria was damaged in the striatal neurons that exhibited the ultrastructural features of apoptosis under rotenone intoxication. As exemplified by a neuron in the striatum (Figure 4A) electron microscopy showed oval nuclear morphology prominent nucleolus normal cytoplasmic density and normal cytoplasmic organelles particularly intact utrastracture of mitochondria (Figure 4D) in the striatal neurons in sham control rats. On the other hand neurons with ultrastructural features of apoptotic cell death were identified in the striatum under systemic rotenone intoxication. After 14 days of rotenone intoxication (3 mg/kg/day) the striatal neurons manifested an early stage of apoptotic changes (Figure 4B). The nucleus was reduced in size but surrounded by an intact membrane. The chromatin was heterochromatic in appearance with mild margination. Intriguingly relatively intact mitochondria (Figure 4E) were clearly recognizable in the cytoplasm of striatal neurons that exhibited early MLN518 MLN518 apoptotic cell death feature. After 28 days of systemic rotenone intoxication striatal neurons presented with Rabbit Polyclonal to EPHA7 (phospho-Tyr791). advanced degree of apoptotic features (Figure 4C) that exhibited a shrinkage appearance of its markedly reduced cell body alongside increased cytoplasmic electron density and high condensation and margination of chromatin in the much-diminished nucleus. Mitochondrial ultrastructural damage was noted after 28 days of systemic rotenone intoxication that was associated with significant swelling of all mitochondrial spaces including cristae and in the advanced cases mitochondrial swelling was accompanied by a disruption in membrane integrity (Figure 4F). Shape 4 Consultant electron photomicrographs of mitochondrial ultrastructure in striatum. (A) A pyramidal neuron with undamaged ultrastructural features in sham-control group; Ultrastructural top features of early (B) or serious (C) apoptotic cell loss of life 14 or 28 … 2.5 Dopaminergic Neuronal Cell Loss and Apoptotic Cell Loss of life in the Striatum and Substantia Nigra Pursuing Chronic Rotenone Intoxication After 28 times of rotenone (3 MLN518 mg/kg/day) exposure imunohistochemical staining for tyrosine hydroxylase demonstrated decreased tyrosine hydroxylase-positive cells in the substantia nigra (Shape 5D) and striatum (Shape 6D) indicating that chronic rotenone intoxication led to nigrostriatal dopaminergic neuronal cell degeneration. Nevertheless the tyrosine hydroxylase staining in the stratum had been relatively regular in sham-control animals (Figures 5A ? 6 Moreover TUNEL and caspase-3 staining were employed to confirm the neuronal nature of the apoptotic cells in the substantia nigra and striatum after chronic rotenone intoxication. TUNEL-positive cells (Figures 5E ? 6 and caspase-3-postive cells (Figures 5F ? 6 appeared on day 28 in the substantia nigra and striatum after systemic infusion of rotenone. On the other hand TUNEL-positive and caspase-3-postive cells were essentially absent in the substantia nigra (Figure 5B C) and striatum (Figure 6B C) in the sham control animals. For quantitative assessment of neuronal MLN518 cell death striatal tissues were collected 7 14 or 28 days after rotenone intoxication and TUNEL-positive cells and caspase-3-postive cells were counted. Significant amounts of TUNEL-positive cells (Figure 6G) and caspase-3-postive cells (Figure 6H) appeared on day 14.