Protective effect of growth hormone on neuronal apoptosis after hypoxia–ischemia in the neonatal rat brain

doi:10.1016/j.neulet.2003.09.070

Neuroscience Letters

Volume 354, Issue 1, 2 January 2004, Pages 64-68

https://doi.org/10.1016/j.neulet.2003.09.070 Get rights and content

Abstract

Recent studies have shown that growth hormone (GH) can reduce neuronal loss after hypoxic-ischemic injury (HI) in neonatal and juvenile rat brains. Here, we investigated whether GH exerts its neuroprotective role through an anti-apoptotic effect in neonatal rat brains damaged by severe HI. Gross and histological observations showed that the extent of brain damage was found to be reduced in GH-treated brain at E7 after injury. In a terminal transferase-mediated dUTP nick-end-labeling (TUNEL) study, TUNEL-positive apoptotic cells were localized only at the damaged region in animals treated with saline, which was confirmed by an electron microscopy. In an immunohistochemical study with anti-bcl-2, -bax, -bad, -neuronal nitric oxide synthase (nNOS), -inducible NOS (iNOS) and -endothelial NOS (eNOS) antibodies, we observed that bax, bad, iNOS and eNOS were elevated in the saline-treated group. This study thus suggests that the protective role of GH against HI injury is mediated thorough an anti-apoptotic effect, which offers the possibility of a GH application for the treatment of neonatal HI encephalopathy.

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Cited by (71)

Evaluation of the anticonvulsant and neuroprotective effect of intracerebral administration of growth hormone in rats
2024, Neurologia
The growth hormone (GH) has been reported as a crucial neuronal survival factor in the hippocampus against insults of diverse nature. Status epilepticus (SE) is a prolonged seizure that produces extensive neuronal cell death. The goal of this study was to evaluate the effect of intracerebroventricular administration of GH on seizure severity and SE-induced hippocampal neurodegeneration.
Adult male rats were implanted with a guide cannula in the left ventricle and different amounts of GH (70, 120 or 220 ng/3 μl) were microinjected for 5 days; artificial cerebrospinal fluid was used as the vehicle. Seizures were induced by the lithium–pilocarpine model (3 mEq/kg LiCl and 30 mg/kg pilocarpine hydrochloride) one day after the last GH administration. Neuronal injury was assessed by Fluoro-Jade B (F-JB) staining.
Rats injected with 120 ng of GH did not had SE after 30 mg/kg pilocarpine, they required a higher number of pilocarpine injections to develop SE than the rats pretreated with the vehicle, 70 ng or 220 ng GH. Prefrontal and parietal cortex EEG recordings confirmed that latency to generalized seizures and SE was also significantly higher in the 120 ng group when compared with all the experimental groups. FJ-B positive cells were detected in the hippocampus after SE in all rats, and no significant differences in the number of F-JB cells in the CA1 area and the hilus was observed between experimental groups.
Our results indicate that, although GH has an anticonvulsive effect in the lithium–pilocarpine model of SE, it does not exert hippocampal neuroprotection after SE.
La hormona de crecimiento (HC) es un factor que favorece la supervivencia neuronal en el hipocampo ante agresiones de diversa naturaleza. El status epilepticus (SE) es un tipo de crisis epiléptica de larga duración que produce muerte neuronal. El objetivo de este estudio fue evaluar el efecto de la administración intracerebroventricular de HC en la severidad de las convulsiones y la neurodegeneración hipocampal debida al SE.
A ratas macho adultas se les implantó una cánula guía en el ventrículo lateral izquierdo y se les microinyectaron diferentes cantidades de HC (70, 120 o 220 ng/3 μl) durante 5 días; como vehículo se inyectó líquido cefalorraquídeo artificial. Las convulsiones se generaron con el modelo de litio-pilocarpina (3 mEq/kg LiCl y 30 mg/kg clorhidrato pilocarpina) un día después de la última inyección de HC. La neurodegeneración se identificó con la tinción de Fluoro-Jade B (F-JB).
Las ratas a las que se les inyectaron 120 ng de HC requirieron 2 o 3 inyecciones de pilocarpina para desarrollar SE, en comparación con el resto de los grupos experimentales que requirieron solo una aplicación del convulsivante. Los registros EEG de la corteza prefrontal y parietal confirmaron que la latencia a las crisis generalizadas y al SE fue mayor en dicho grupo experimental. Todas las ratas con SE presentaron células positivas al FJ-B en el área CA1 e hilus del hipocampo, y no se identificaron diferencias entre los tratamientos.
Nuestros resultados muestran que, aunque la HC tiene un efecto anticonvulsivante, una vez que se ha desarrollado el SE no promueve neuroprotección en el hipocampo.
The role of growth hormone in hippocampal function
2022, Vitamins and Hormones
Citation Excerpt :
The CA1 region of the hippocampus and the frontal cortex are brain areas that are particularly sensitive to hypoxia injury, which may explain the neurocognitive deficits reported. Experimental studies in neonatal rats subjected to hypoxia showed that GH administration reduced neuronal death through an antiapoptotic mechanism (Gustafson, Hagberg, Bengtsson, Brantsing, & Isgaard, 1999; Shin et al., 2004). The antiapoptotic effect of GH in the damaged brain is mediated by the increased levels of the antiapoptotic protein of Bcl-2, a decrease in caspase-3 activity, and by an increased Akt phosphorylation (Costoya et al., 1999).
Growth hormone is a multifunctional molecule with broad cellular targets. This pituitary hormone is currently used as a therapeutic agent against several brain injuries due to its neurotrophic activity. The hippocampus is one of the brain regions where the growth hormone plays a role in normal and pathologic conditions. This brain structure is associated with several cognitive functions such as learning, memory, and mood, which are frequently affected by brain traumatism. The present chapter describes the experimental and clinical evidence that supports a central role of growth hormone in the hippocampus functionality.
Aquatic hypoxia disturbs oriental river prawn (Macrobrachium nipponense) testicular development: A cross-generational study
2020, Environmental Pollution
Recently, we reported that hypoxia disrupts the endocrine system and causes metabolic abnormalities in prawns. Although transgenerational impairment effects of hypoxia have become a hot topic in vertebrate, it is unknown whether hypoxia could exert cross-generational effects on testicular function crustaceans. The present study aimed to investigate hypoxia’s toxic effects on the testicular function of oriental river prawns (Macrobrachium nipponense) and offspring development. Hypoxia disrupted testicular germ cells quality, caused sex hormone imbalance (testosterone and estradiol), and delayed testicular development. The F1 generation derived from male prawns exposed to hypoxia showed retarded embryonic development, and reduced hatching success and larval development, despite not being exposed to hypoxia. Analysis of the transcriptome the F0 generation (exposed to hypoxia) showed that the impaired testicular functions were associated with changes to mitochondrial oxidative phosphorylation, apoptosis, and steroid biosynthesis. Interestingly, quantitative real-time PCR confirmed that hypoxia could significantly suppress the expression of antioxidant and gonad development-related genes in the testis of the F1 generations, with and without continued hypoxia exposures. In addition, paternal exposure to hypoxia could result in a higher production of reactive oxygen species in offspring testis tissue compared with those without hypoxia exposure. The cross-generational effects of testicular function implied that the sustainability of natural freshwater prawn populations would be threatened by chronic hypoxia.
Growth hormone reverses excitotoxic damage induced by kainic acid in the green iguana neuroretina
2016, General and Comparative Endocrinology
It is known that growth hormone (GH) is expressed in extrapituitary tissues, including the nervous system and ocular tissues, where it is involved in autocrine/paracrine actions related to cell survival and anti-apoptosis in several vertebrates. Little is known, however, in reptiles, so we analyzed the expression and distribution of GH in the eye of green iguana and its potential neuroprotective role in retinas that were damaged by the intraocular administration of kainic acid (KA). It was found, by Western blotting, that GH-immunoreactivity (GH-IR) was expressed as two isoforms (15 and 26 kDa, under reducing conditions) in cornea, vitreous, retina, crystalline, iris and sclera, in varying proportions. Also, two bands for the growth hormone receptor (GHR)-IR were observed (70 and 44 kDa, respectively) in the same tissues. By immunofluorescence, GH-IR was found in neurons present in several layers of the neuroretina (inner nuclear [INL], outer nuclear [ONL] and ganglion cell [GCL] layers) as determined by its co-existence with NeuN, but not in glial cells. In addition, GH and GHR co-expression was found in the same cells, suggesting paracrine/autocrine interactions. KA administration induced retinal excitotoxic damage, as determined by a significant reduction of the cell density and an increase in the appearance of apoptotic cells in the INL and GCL. In response to KA injury, both endogenous GH and Insulin-like Growth Factor I (IGF-I) expression were increased by 70 ± 1.8% and 33.3 ± 16%, respectively. The addition of exogenous GH significantly prevented the retinal damage produced by the loss of cytoarchitecture and cell density in the GCL (from 4.9 ± 0.79 in the control, to 1.45 ± 0.2 with KA, to 6.35 ± 0.49 cell/mm² with KA + GH) and in the INL (19.12 ± 1.6, 10.05 ± 1.9, 21.0 ± 0.8 cell/mm², respectively) generated by the long-term effect of 1 mM KA intraocular administration. The co-incubation with a specific anti-GH antibody, however, blocked the protective effect of GH in GCL (1.4 ± 0.23 cell/mm²) and INL (11.35 ± 1.06), respectively. Furthermore, added GH induced an increase of 90 ± 14% in the retinal IGF-I concentration and the anti-GH antibody also blocked this effect. These results indicate that GH and GHR are expressed in the iguana eye and may be able to exert, either directly of mediated by IGF-I, a protective mechanism in neuroretinas that suffered damage by the administration of kainic acid.
Growth hormone overexpression generates an unfavorable phenotype in juvenile transgenic zebrafish under hypoxic conditions
2013, General and Comparative Endocrinology
Citation Excerpt :
Furthermore, the presence of GH receptors (GHR) in several types of central nervous system (CNS) cells indicates that this hormone also influences nervous system functions (Aberg et al., 2006). Previous studies in rats have shown that GH administration may prevent damage caused by hypoxia–ischemia by inhibiting neuronal death (Gustafson et al., 1999) and inducing an anti-apoptotic effect (Shin et al., 2004). These studies suggest an application for treating neonatal pathologies induced by hypoxia.
Growth hormone (GH) has numerous functions in different organisms. A recently described function for GH is its role in protecting against damage caused by a decrease in oxygen levels. To evaluate the effects of GH-transgenesis on hypoxia tolerance, we used a GH-transgenic zebrafish model. We found that the transgenic fish have higher mortality rates when exposed to low oxygen levels (1.5 mg O₂ L⁻¹) for 24 h. The lower capacity of GH-transgenic fish to manage a hypoxic environment was investigated by analyzing different metabolic and molecular factors. The transgenic fish showed increased oxygen consumption, which confirms the larger oxygen demand imposed by transgenesis. At the gene expression level, transgenesis increased lactate dehydrogenase (LDH) and creatine kinase muscle (CKM) expression in fish under normoxic conditions. This result suggests that excessive GH expression stimulates the synthesis of enzymes involved in anaerobic metabolism. Conversely, the interaction between transgenesis and hypoxia caused an increased expression of hemoglobin (Hb), hypoxia-inducible factor (HIF1a) and prolyl-4-hydroxylase (PHD) genes. Additionally, GH-transgenesis increased LDH activity and increased lactate content. Taken together, these findings indicate that GH-transgenesis impaired the ability of juvenile zebrafish to sustain an aerobic metabolism and induced anaerobic metabolism when the fish were challenged with low oxygen levels.
Oligodendrocyte progenitor cells' fate after neonatal asphyxia—Puzzling implications for the development of hypoxic–ischemic encephalopathy
2024, Brain Pathology

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Protective effect of growth hormone on neuronal apoptosis after hypoxia–ischemia in the neonatal rat brain

Abstract

Brain Res. Mol. Brain Res.

Biochim. Biophys. Acta

Mol. Cell. Endocrinol.

Brain Res. Dev. Brain Res.

Brain Res. Mol. Brain Res.

Neuroscience

Neurosci. Lett.

Tissue processing, microtomy and paraffin sections

The relationship between BcI2, Bax and p53: consequences for cell cycle progression and cell death [review]

Mol. Hum. Reprod.

Growth hormone receptor messenger ribonucleic acid distribution in the adult male rat brain and its colocalization in hypothalamic somatostatin neurons

Endocrinology