Effects of GnRH on Neurite Outgrowth, Neurofilament and Spinophilin Proteins Expression in Cultured Spinal Cord Neurons of Rat Embryos

Neurological recovery in rats with portocaval anastomosis-induced hepatic encephalopathy treated with leuprolide acetate, a GnRH agonist

Hepatic encephalopathy (HE) is a neuropsychiatric complication of acute liver failure or chronic liver injury. Liver dysfunction impairs ammonia detoxification, allowing it to cross the blood-brain barrier (BBB) and disrupt brain function. The hippocampus becomes a crucial target during elevated ammonia levels, causing spatial memory impairment and decreased learning ability. Leuprolide acetate (LA), a GnRH agonist, has been implicated in neuroprotection and neuroregeneration in several regions of the central nervous system (CNS) including hippocampus. In this study, we aim to evaluate the effects of LA treatment on hippocampus of rats with HE induced by portocaval anastomosis (PCA) trough cognitive tests, histology analysis and expression of neuronal recovery marker proteins, such as neurofilament (NF200) and neurabin II, and astrocyte marker glial fibrillary acidic protein (GFAP). Rats were divided into three groups: SHAM, portocaval anastomosis with saline solution (PCA + SS) and portocaval anastomosis treated with LA (PCA + LA). To evaluate learning and spatial memory elevated T-maze (ETM) and Y-maze test (YMT) were respectively used. Results indicated that LA-treated rats performed significantly better in ETM and YMT than untreated rats. Histological analysis of hippocampus showed increased neuron density, nuclear area, and layer thickness in dentate gyrus of PCA + LA group compared to PCA + SS. Additionally, neurabin II and NF200 expression were higher in LA-treated rats, while GFAP expression was elevated in the PCA + SS group compared to control and PCA + LA groups. In conclusion, LA enhances hippocampal neuron recovery and reduces astrogliosis, suggesting its potential as a therapeutic intervention for attenuating hippocampal damage during HE.

Analysis of hippocampus in rats with acute brain ischemia-reperfusion injury treated with leuprolide acetate, an agonist of GnRH

BACKGROUND

The hippocampus is highly vulnerable to damage in the brain ischemia-reperfusion injury model. Leuprolide acetate has been shown to promote neurological recovery after injury in various regions of the central nervous system.

OBJECTIVE

The objective of this study was to assess the histology of the hippocampus and the expression of neuronal recovery markers, specifically the 200 kDa neurofilaments and the myelin basic protein, in rats with brain ischemia-reperfusion injury treated with leuprolide acetate.

METHODS

The rats were divided into three groups: Sham, ischemia-reperfusion with saline solution, and ischemia-reperfusion treated with leuprolide acetate. Coronal brain slices were obtained and stained with hematoxylin-eosin. The histological analysis involved quantifying the number of neurons in the hippocampal regions CA1, CA3 and DG. The myelin basic protein and neurofilaments were quantified using western blot.

RESULTS

The number of neurons in CA1 and DG was significantly higher in the leuprolide acetate group compared to the untreated group. Additionally, the expression of neurofilament and myelin basic protein markers was significantly increased in rats treated with leuprolide acetate compared to the untreated rats.

CONCLUSIONS

Leuprolide acetate promotes the recovery of hippocampal neurons in an acute brain ischemia-reperfusion injury model. These findings suggest that leuprolide acetate could be a potential therapeutic intervention for reversing damage in hippocampal ischemic lesions.

Neonatal Hypoxic-Ischemic Encephalopathy: Perspectives of Neuroprotective and Neuroregenerative Treatments

Hypoxic-ischemic encephalopathy (HIE) is a serious condition that could have deleterious neurological outcomes, such as cerebral palsy, neuromotor disability, developmental disability, epilepsy, and sensitive or cognitive problems, and increase the risk of death in severe cases. Once HIE occurs, molecular cascades are triggered favoring the oxidative stress, excitotoxicity, and inflammation damage that promote cell death via apoptosis or necrosis. Currently, the therapeutic hypothermia is the standard of care in HIE; however, it has a small window of action and only can be used in children of more than 36 gestational weeks; for this reason, it is very important to develop new therapies to prevent the progression of the hypoxic-ischemic injury or to develop neuroregenerative therapies in severe HIE cases. The objective of this revision is to describe the emerging treatments for HIE, either preventing cell death for oxidative stress, excitotoxicity, or exacerbated inflammation, as well as describing a new therapeutic approach for neuroregeneration, such as mesenchymal stem cells, brain-derived neurotrophic factor, and gonadotropin realizing hormone agonists.

EA Improves the Motor Function in Rats with Spinal Cord Injury by Inhibiting Signal Transduction of Semaphorin3A and Upregulating of the Peripheral Nerve Networks

Peripheral nerve networks (PNNs) play a vital role in the neural recovery after spinal cord injury (SCI). Electroacupuncture (EA), as an alternative medicine, has been widely used in SCI and was proven to be effective on neural functional recovery. In this study, the interaction between PNNs and semaphrin3A (Sema3A) in the recovery of the motor function after SCI was observed, and the effect of EA on them was evaluated. After the establishment of the SCI animal model, we found that motor neurons in the ventral horn of the injured spinal cord segment decreased, Nissl bodies were blurry, and PNNs and Sema3A as well as its receptor neuropilin1 (NRP1) aggregated around the central tube of the gray matter of the spinal cord. When we knocked down the expression of Sema3A at the damage site, NRP1 also downregulated, importantly, PNNs concentration decreased, and tenascin-R (TN-R) and aggrecan were also reduced, while the Basso-Beattie-Bresnahan (BBB) motor function score dramatically increased. In addition, when conducting EA stimulation on Jiaji (EX-B2) acupoints, the highly upregulated Sema3A and NRP1 were reversed post-SCI, which can lessen the accumulation of PNNs around the central tube of the spinal cord gray matter, and simultaneously promote the recovery of motor function in rats. These results suggest that EA may further affect the plasticity of PNNs by regulating the Sema3A signal and promoting the recovery of the motor function post-SCI.

Recovery of sciatic nerve with complete transection in rats treated with leuprolide acetate: A gonadotropin-releasing hormone agonist

It has been reported that the Gonadotropin-releasing hormone (GnRH) and its agonist leuprolide acetate (LA) can act as promoters of nerve regeneration. The aim of this study is to evaluate the effect of LA in a complete transection model. Sciatic nerve injury (SNI) was performed using a complete nerve transection and immediately repaired by epineural sutures. Rats were divided into three groups: SHAM, SNI treated with LA (SNI + LA) or saline solution (SNI + SS) for 5 weeks. Sciatic nerve regeneration was evaluated by kinematic gait analyzes, electrophysiological, morphological and biochemical tests. SNI + LA group had a functional recovery in kinematic gait, an increase in ankle angle value and a faster walking speed, compound muscle action potential amplitude, nerve conduction velocity (NCV). Furthermore, the number of myelinated axons and microtubule-associated protein 2 (MAP-2) expression were also higher compared to SS group. In conclusion, LA treatment improves of gait, walking speed, NCV, axons morphometry and MAP-2 expression in rats with sciatic nerve complete transection. These results suggest that LA can be a potential treatment for peripheral nerve injuries.

Leuprolide Acetate, a GnRH Agonist, Improves the Neurogenic Bowel in Ovariectomized Rats with Spinal Cord Injury

BACKGROUND

Electromyographic studies have shown that external anal sphincter activity is modified in response to distension in animals with spinal cord injury. Gonadotropin-releasing hormone and its agonist leuprolide acetate have neurotrophic properties in animals with spinal cord injury.

AIM

This study was to determine the effects of leuprolide acetate treatment on electromyographic activity of the external anal sphincter and anorectal manometry in ovariectomized rats with spinal cord injury.

METHODS

Adult ovariectomized rats were divided in three groups: (a) sham of spinal cord injury, (b) spinal cord injury treated with saline solution, and (c) spinal cord injury treated with leuprolide acetate. The spinal cord injury was induced by clamping at level T9. Leuprolide acetate dosage of 10 μg/kg was proctored intramuscular for 5 weeks, commencing the day after the lesion. Electromyography of the external anal sphincter, anorectal manometry, and volume of the cecum were evaluated in all groups.

RESULTS

The electromyographic study of the external anal sphincter activity showed a significant improvement in injured rats treated with leuprolide acetate. Manometric analysis and cecum volume data obtained in animals with leuprolide acetate were very similar to those found in the sham group.

CONCLUSIONS

These results demonstrate that leuprolide acetate treatment improves the neurogenic colon in ovariectomized rats with spinal cord injury.

Growth Hormone (GH) and Gonadotropin-Releasing Hormone (GnRH) in the Central Nervous System: A Potential Neurological Combinatory Therapy?

This brief review of the neurological effects of growth hormone (GH) and gonadotropin-releasing hormone (GnRH) in the brain, particularly in the cerebral cortex, hypothalamus, hippocampus, cerebellum, spinal cord, neural retina, and brain tumors, summarizes recent information about their therapeutic potential as treatments for different neuropathologies and neurodegenerative processes. The effect of GH and GnRH (by independent administration) has been associated with beneficial impacts in patients with brain trauma and spinal cord injuries. Both GH and GnRH have demonstrated potent neurotrophic, neuroprotective, and neuroregenerative action. Positive behavioral and cognitive effects are also associated with GH and GnRH administration. Increasing evidence suggests the possibility of a multifactorial therapy that includes both GH and GnRH.