Effects of Prenatal Methcathinone Exposure on the Neurological Behavior of Adult Offspring

BACKGROUND

Our previous research has shown that prenatal methcathinone exposure affects the neurodevelopment and neurobehavior of adolescent offspring, but the study on whether these findings continue into adulthood is limited.

OBJECTIVE

This study aims to explore the effects of prenatal methcathinone exposure on anxiety-like behavior, learning and memory abilities, as well as serum 5-hydroxytryptamine and dopamine concentrations in adult offspring.

METHODS

Pregnant rats were injected daily with methcathinone between the 7th and 20th days of gestation. The neurobehavioral performance of both male and female adult offspring rats was evaluated by neurobehavioral tests, including open-field tests, Morris water maze (MWM) tests, and novel object recognition (NOR) tests. The levels of 5-hydroxytryptamine and dopamine concentration in rat serum were detected by ELISA.

RESULTS

Significant differences were found in the length of center distance and time of center duration in the open-field test, as well as the times of crossing the platform in the MWM test, between the prenatal methcathinone exposure group and the control group. Results of the NOR test showed that adult offspring rats exposed to methcathinone need more time to discriminate the novel object. No gender differences were detected in the neurobehavioral tests. The serum concentrations of 5-hydroxytryptamine and dopamine in rats exposed to methcathinone prenatally were lower than that in the control group, and the serum dopamine concentration was independent of gender in each group.

CONCLUSION

Prenatal methcathinone exposure affects the neurological behavior in adult offspring, and 5-hydroxytryptamine and dopamine might be involved in the process.

Oxidized low-density lipoprotein receptor 1: a novel potential therapeutic target for intracerebral hemorrhage

Oxidized low-density lipoprotein receptor 1 (OLR1) is upregulated in neurons and participates in hypertension-induced neuronal apoptosis. OLR1 deletion exerts protective effects on cerebral damage induced by hypertensive-induced stroke. Therefore, OLR1 is likely involved in the progress of intracerebral hemorrhage. In this study, we examined the potential role of OLR1 in intracerebral hemorrhage using a rat model. OLR1 small interfering RNA (10 μL; 50 pmol/μL) was injected into the right basal ganglia to knock down OLR1. Twenty-four hours later, 0.5 U collagenase type VII was injected to induce intracerebral hemorrhage. We found that knockdown of OLR1 attenuated neurological behavior impairment in rats with intracerebral hemorrhage and reduced hematoma, neuron loss, inflammatory reaction, and oxidative stress in rat brain tissue. We also found that silencing of OLR1 suppressed ferroptosis induced by intracerebral hemorrhage and the p38 signaling pathway. Therefore, silencing OLR1 exhibits protective effects against secondary injury of intracerebral hemorrhage. These findings suggest that OLR1 may be a novel potential therapeutic target for intracerebral hemorrhage.

Transplantation of Hematopoietic Stem Cells Promotes Functional Improvement Associated with NT-3-MEK-1 Activation in Spinal Cord-Transected Rats

Transected spinal cord injury (SCT) is a devastating clinical disease that strongly affects a patient’s daily life and remains a great challenge for clinicians. Stem-cell therapy has been proposed as a potential therapeutic modality for SCT. To investigate the effects of hematopoietic stem cells (HSCs) on the recovery of structure and function in SCT rats and to explore the mechanisms associated with recovery, 57 adult Sprague-Dawley rats were randomly divided into sham (n = 15), SCT (n = 24), and HSC transplantation groups (n = 15). HSCs (passage 3) labeled by Hoechst 33342, were transplanted intraspinally into the rostral, scar and caudal sites of the transected lesion at 14 days post-operation. Both in vitro and in vivo, HSCs exhibited a capacity for cell proliferation and differentiation. Following HSC transplantation, the animals’ Basso, Beattie, and Bresnahan (BBB). locomotion scale scores increased significantly between weeks 4 and 24 post-SCT, which corresponded to an increased number of 5-hydroxytryptamine (5-HT) fibers and oligodendrocytes. The amount of astrogliosis indicated by immunohistochemical staining, was markedly decreased. Moreover, the decreased expression of neurotrophin- 3 (NT-3) and mitogen-activated protein kinase kinase-1 (MEK-1) after SCT was effectively restored by HSC transplantation. The data from the current study indicate that intraspinally administered HSCs in the chronic phase of SCT results in an improvement in neurological function. Further, the results indicate that intraspinally administered HSCs benefit the underlying mechanisms involved in the enhancement of 5-HT-positive fibers and oligogenesis, the suppression of excessive astrogliosis and the upregulation of NT3-regulated MEK-1 activation in the spinal cord. These crucial findings reveal not only the mechanism of cell therapy, but may also contribute to a novel therapeutic target for the treatment of spinal cord injury (SCI).

Verbascoside promotes the regeneration of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra

Tyrosine hydroxylase is a key enzyme in dopamine biosynthesis. Change in tyrosine hydroxylase expression in the nigrostriatal system is closely related to the occurrence and development of Parkinson's disease. Verbascoside, an extract from Radix Rehmanniae Praeparata has been shown to be clinically effective in treating Parkinson's disease. However, the underlying mechanisms remain unclear. It is hypothesized that the effects of verbascoside on Parkinson's disease are related to tyrosine hydroxylase expression change in the nigrostriatal system. Rat models of Parkinson's disease were established and verbascoside (60 mg/kg) was administered intraperitoneally once a day. After 6 weeks of verbascoside treatment, rat rotational behavior was alleviated; tyrosine hydroxylase mRNA and protein expression and the number of tyrosine hydroxylase-immunoreactive neurons in the rat right substantia nigra were significantly higher than the Parkinson's model group. These findings suggest that the mechanism by which verbascoside treats Parkinson's disease is related to the regeneration of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra.

Hydrogen sulfide improves neural function in rats following cardiopulmonary resuscitation

The alleviation of brain injury is a key issue following cardiopulmonary resuscitation (CPR). Hydrogen sulfide (H₂S) is hypothesized to be involved in the pathophysiological process of ischemia-reperfusion injury, and exerts a protective effect on neurons. The aim of the present study was to investigate the effects of H₂S on neural functions following cardiac arrest (CA) in rats. A total of 60 rats were allocated at random into three groups. CA was induced to establish the model and CPR was performed after 6 min. Subsequently, sodium hydrosulfide (NaHS), hydroxylamine or saline was administered to the rats. Serum levels of H₂S, neuron-specific enolase (NSE) and S100β were determined following CPR. In addition, neurological deficit scoring (NDS), the beam walking test (BWT), prehensile traction test and Morris water maze experiment were conducted. Neuronal apoptosis rates were detected in the hippocampal region following sacrifice. After CPR, as the H₂S levels increased or decreased, the serum NSE and S100β concentrations decreased or increased, respectively (P<0.0w. The NDS results of the NaHS group were improved compared with those of the hydroxylamine group at 24 h after CPR (P<0.05). In the Morris water maze experiment, BWT and prehensile traction test the animals in the NaHS group performed best and rats in the hydroxylamine group performed worst. At day 7, the apoptotic index and the expression of caspase-3 were reduced in the hippocampal CA1 region, while the expression of Bcl-2 increased in the NaHS group; and results of the hydroxylamine group were in contrast. Therefore, the results of the present study indicate that H₂S is able to improve neural function in rats following CPR.