Cell Proliferation in the Piriform Cortex of Rats with Motor Cortex Ablation Treated with Growth Hormone and Rehabilitation

Abstract

Traumatic brain injury represents one of the main health problems in developed countries. Growth hormone (GH) and rehabilitation have been claimed to significantly contribute to the recovery of lost motor function after acquired brain injury, but the mechanisms by which this occurs are not well understood. In this work, we have investigated cell proliferation in the piriform cortex (PC) of adult rats with ablation of the frontal motor cortex treated with GH and rehabilitation, in order to evaluate if this region of the brain, related to the sense of smell, could be involved in benefits of GH treatment. Male rats were either ablated the frontal motor cortex in the dominant hemisphere or sham-operated and treated with GH or vehicle at 35 days post-injury (dpi) for five days. At 36 dpi, all rats received daily injections of bromodeoxyuridine (BrdU) for four days. We assessed motor function through the paw-reaching-for-food task. GH treatment and rehabilitation at 35 dpi significantly improved the motor deficit caused by the injury and promoted an increase of cell proliferation in the PC ipsilateral to the injury, which could be involved in the improvement observed. Cortical ablation promoted a greater number of BrdU+ cells in the piriform cortex that was maintained long-term, which could be involved in the compensatory mechanisms of the brain after injury.

Delayed Diagnosis of Congenital Combined Pituitary Hormone Deficiency including Severe Growth Hormone Deficiency in Children with Persistent Neonatal Hypoglycemia—Case Reports and Review

“…Early rhGH substitution is important not only for correcting hypoglycemia and maintaining normal linear growth, but also for improvement of psychomotor development, as has been observed in our patients. Similar beneficial effects of rhGH administration have previously been reported in the studies on rats after experimental brain injuries (recovery of lost motor function) [ 29 ], as well as humans [ 30 , 31 ].…”

“…An interesting issue is GH’s contributions to cell proliferation and recovery of lost motor functions after brain injuries or cortical ablation, documented in the studies on rats [ 29 , 54 ]. The therapy with rhGH may contribute to recovery in children with cerebral palsy [ 30 ], after asphyxia during delivery [ 31 ], after traumatic brain injury [ 55 ] or with congenital defects of spinal cord development (caudal regression syndrome) [ 56 ].…”

Gonadotropin-releasing hormone and growth hormone act as anti-inflammatory factors improving sensory recovery in female rats with thoracic spinal cord injury

“…In the sham group, surgery was performed as usual, but omitting the damaging step: the catheter insufflation. Treatments were administered as follows: Human recombinant gonadotropin-releasing hormone (GnRH, 0.06 mg/kg) (L7134, Sigma, MO, USA) was injected every 12 h by intramuscular (IM) administration (Calderón-Vallejo and Quintanar, 2012); a single daily dose (0.15 mg/kg; Heredia et al, 2021) of human recombinant growth hormone (rhGH) (somatropin; Genotropin C, Pfizer, México) was subcutaneously (SC) administered in the morning; and vehicle (100 µL of saline solution, 0.9% NaCl in distilled water) was administered IM (Figure 1). The treatments started 24 h after the SCI surgery and stopped 24 h before euthanasia.…”