Neuroprotective effect of green tea extract (-)-epigallocatechin-3-gallate in a preformed fibril-induced mouse model of Parkinson's disease.

Parkinson's disease (PD) is the second most common neurodegenerative disease characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra (SN). The main bioactive component of green tea polyphenols (-)-epigallocatechin-3-gallate (EGCG) exerts protective effects against diseases such as neurodegenerative diseases and cancer. Therefore, this study investigated the effect of EGCG on the amelioration of neural damage in a chronic PD mouse model induced by α-synuclein preformed fibrils (α-syn-PFFs). A total of 20 C57BL/6J female mice were randomly divided into 3 groups: control group (saline, n = 6), model group (PFFs, n = 7), and prevention group (EGCG+PFFs, n = 7). A chronic PD mouse model was obtained by the administration of α-syn-PFFs by stereotaxic localization in the striatum. Behavioral tests were performed to evaluate PD-related anxiety-like behavior and motor impairments in the long-term PD progression. Tyrosine hydroxylase (TH) immuno-positive neurons and Ser129-phosphorylated α-syn (p-α-syn) were identified by immunohistochemistry. Pro-inflammatory and anti-inflammatory cytokines were measured by real-time quantitative PCR. EGCG pretreatment reduced anxiety-like behavior and motor impairments as revealed by the long-term behavioral test (2 weeks, 1 month, 3 months, and 6 months) on PD mice. EGCG also ameliorated PFF-induced degeneration of TH immuno-positive neurons and accumulation of p-α-syn in the SN and striatum at 6 months. Additionally, EGCG reduced the expression of pro-inflammatory cytokines while promoting the release of anti-inflammatory cytokines. EGCG exerts a neuroprotective effect on long-term progression of the PD model.

Spatiotemporal differences in phosphorus release potential of bloom-forming cyanobacteria in Lake Taihu.

The abnormal elevation of cyanobacterial density and total phosphorus concentration after the reduction of exogenous pollutants in Lake Taihu is still an open question. An in-situ light-dark bottle method was used to investigate the spatiotemporal differences of phosphorus release potential of bloom-forming cyanobacteria (BFC) in Lake Taihu. Generalized additive model analysis (GAM) of field data revealed that the phosphorus release potential of BFC increased with the upregulation of Chlorophyll a (Chl-a) content per cell, which was further validated by the laboratory experiment results. We deduced that the accumulation of Chl-a content per cell might be an essential index of high phosphorus release potential of BFC. The phosphorus release potential of BFC was much higher in summer and autumn than that in spring and winter, while the phosphorus absorption potential increased with the rising of temperature. The distinct physiological status of BFC at different seasons brought about their variation in phosphorus release potential. Additionally, high phosphorus release potential of BFC region mainly concentrated in the eastern and the central, northwest, western, and the south of Lake Taihu in spring, summer, autumn, and winter, respectively. Further studies showed that the spatial differences in phosphorus release potential of BFC were most probably due to the horizontal drift of BFC driven by the prevailing wind. Collectively, the synergism of BFC's physiological status and horizontal drift determined the spatiotemporal differences of phosphorus release potential of BFC in Lake Taihu. Moreover, apparent spatiotemporal differences in phosphorus release potential of BFC were essential factors that induced the distinct distribution of total phosphorus in Lake Taihu. This study provides insight for exploring the reason for the constant increase of total dissolved phosphorus concentration and cyanobacterial density in Lake Taihu for the past 5 years.