Peptides semax and selank affect the behavior of rats with 6-OHDA induced PD-like parkinsonism

Evaluating Some Parameters Of Wistar Rat Brain In Traumatic Brain Injury Model With Administration Of Proline-Containing Peptides

Objective — To examine the morphometric parameters of neurons and the oxidative status of the Wistar rat brain tissues after administering proline-containing peptides, also known as glyprolines (Arg-Gly-Arg-Pro-Gly-Pro [RGRPGP] and Thr-Lys-Pro-Arg-Pro-Gly-Pro [WKPRPGP; Selank]), on a traumatic brain injury (TBI) model. Study subjects — Our study involved 26 mature male Wistar rats (2.5-3 mos. old, 220-300 g). The morphometric parameters of neurons and the oxidative status of animal brain tissues were studied. Material and Methods — Four experimental groups were formed. Group 1 included intact control animals. Animals in three other groups were subjected to TBI via free fall of a 50 g weight from a height of 50 cm on the second day of the experiment and received the following injections: 0.9% sodium chloride solution in Group 2; WKPRPGP peptide solution in Group 3; RGRPGP peptide solution in Group 4. Substances were administered intraperitoneally on a daily basis at a dose of 0.1 mg/kg from day 1 through day 5 of the experiment. Morphometric parameters of rat brain neurons were studied on paraffin sections stained with hematoxylin and eosin. The intensity of free radical processes in the brain tissue was investigated by chemiluminescence. Results — An analysis of morphometric parameters revealed significant increases in the neuronal cytoplasm area, nucleolar area, number of nucleoli, and nuclear-nucleolar index with the introduction of the RGRPGP peptide after TBI, compared with the WKPRPGP peptide under the same conditions. After TBI and peptide administration, we observed an oxidative stress in the neocortex of Wistar rats, and it was more pronounced in the group of animals treated with RGRPGP. Conclusion — After RGRPGP peptide administration, we observed an increase in the morphometric parameters of neurons in the closed TBI model: a larger area and a greater number of nucleoli. Chemiluminescence data implied that WKPRRPGP peptide better protected brain tissue in rats from the effects of oxidative stress caused by TBI.

Antrodia camphorata polysaccharide resists 6-OHDA-induced dopaminergic neuronal damage by inhibiting ROS-NLRP3 activation

INTRODUCTION

Parkinson's disease (PD) is a common degenerative disease of the central nervous system (CNS). The main pathological change is the apoptosis of dopaminergic neurons in the substantia nigra pars compacta (SNPc), thereby leading to dopamine reduction in nigral striatum. 6-Hydroxydopamine (6-OHDA), a neurotoxic substance, mediates apoptosis of dopaminergic neurons and causes Parkinson-like symptoms in mice.

METHODS

Our team previously found that Antrodia camphorata polysaccharide (ACP) exerted a good behavioral improvement effect on the PD mouse model established by 6-OHDA; however, the mechanism remains unknown. Therefore, in this study, we focused on ROS-NLRP3 signal to investigate the mechanism of 6-OHDA-induced apoptosis of dopaminergic neurons MES23.5 and the protective effects of ACP on dopaminergic neurons.

RESULT

6-OHDA could further activate the expression of inflammasome NLRP3 by inducing ROS, thereby resulting in apoptosis of MES23.5 cells. ACP could inhibit the expression of ROS-NLRP3 induced by 6-OHDA, exerting a protective role in MES23.5 cells. Animal experiments also confirmed that ACP intervention could reduce the activation level of ROS-NLRP3 in the substantia nigra-striatum and improve the exercise capacity of PD mice.

CONCLUSION

Our study validated that 6-OHDA could induce apoptosis of dopaminergic neurons via ROS-NLRP3 activation. ACP could inhibit this signal and protect dopaminergic neurons, which might be promising in research of PD therapeutics.

An integrated approach to study the molecular aspects of regulatory peptides biological mechanism

An integrated methodological approach to study the molecular aspects of short regulatory neuropeptides biological mechanism is proposed. The complex research is based on radioligand-receptor method of analysis and covers such points of peptides molecular activity as: specific binding of peptides to brain cells plasmatic membranes, formation of tissue specific synacton, influence of peptides (as allosteric modulators) on functionality of different neuroreceptors as well as delayed in time effects of peptides on receptor-binding activity of well-known neuroreceptor systems. Radiolabeled ligands in such complex study are the one of the best and precision instruments to uncover the molecular mechanism of multiple and multitarget biological effects of regulatory peptides. In this issue we used heptapeptide Semax as a model regulatory peptide, [³ H]Ach and [³ H]GABA as an effector molecules, and the rat model of stress-induced memory and behavior impairment as a morbid state. We showed the ability of Semax to modulate in a dose-dependent manner [³ H]Ach and [³ H]GABA specific binding to some of its corresponding receptors as well as to affect the number of [³ H]GABA specific binding places on rat neurons plasmatic membranes after complex stress exposure.