The Studies On Apoptotic Mechanism Of Sub-Chronic Avermectin In King Pigeon’s Brain

Avermectin (AVM) was a kind of high efficient, broad spectrum pesticide for animal and for agriculture. It was an excellent helminthicide and had a security. But with the use of AVM increasing, there were more and more accumulation in the environment. And it had a bad effect on ecological system.The pigeon and the quail had a very strong sensitivity of the chemical changes in the environment. The nervous tissue of king pigeon in vivo were the research target, Neurons in king pigeon were infected with AVM at final concentrations of Omg/(kg·diet),20mg/(kg·diet),40mg/(kg·diet) and60mg/(kg·diet) respectively in vivo at different times which were30d,60d and90d. Pathologic histology, changes of ultramicrostructure, oxidative stress, DNA injury, apoptosis, Bcl-2and a-Syn mRNA expression level was detected to study time and dose-response relationship of apoptosis caused by AVM. The results were as followed:1. HE staining, Transmission electron microscopy and Tunel were selected to observe the toxic effect of AVM at different dosages and times against the nervous tissue, AVM could lead to nerve apoptosis observed from morphology, it was showed colinearity definitely between apoptosis ratio and the density of AVM.2. By detecting the activity of anti-oxidative index, and the content of carbonyl, the results revealed that AVM could induce oxidative stress of nerve cells, decrease activities of GSH-PX and SOD, increase the content of MDA and carbonyl in different groups, it showed a determinate dosage and time relationship, it hinted that AVM could lead to oxidative stress of king pigeon’s nervous tissue and would affect its normal physiological function, further induce the apoptosis.3. The rate of DNA-protein cross link in king pigeon’s nervous tissue was detected by KC1-SDS precipitation. The rusults showed that, increase the rate of DNA-protein cross link in king pigeon’s nervous tissue, it showed a determinate dosage and time relationship, it hinted that AVM could lead to DNA toxicity of king pigeon’s nervous tissue, further induce the apoptosis.4. The a-Syn mRNA、bcl-2mRNA expression level in nervous tissue was detected by fluorescent quantitation RT-PCR, the result showed that AVM could lead to increasing of a-Syn mRNA expression level and decreasing of bcl-2mRNA expression level in pigeon nervous tissue, which was the signature genes of apoptosis. And, they were important for apoptosis in king pigeon.From the perspectives of cell morphous, oxidative stress, DNA damage, apoptosis, the mechanism of apoptosis caused by AVM was elucidated. It provided information for further research and provided a scientific basis to protect ecological environment and ensure the development of graziery.