Abstract
<title>Abstract</title> <p> <bold>Background and Objective:</bold> The objective of this study is to evaluate the therapeutic effect of two known peptides on traumatic brain injury (TBI) in rats. <bold>Methods</bold> : After approval from the Institutional Review Board and the Main Committee for Animal Care of Imam AbdulRahman Bin Faisal University, Dammam, Saudi Arabia, the study began. A total of 30 skeletally mature Sprague-Dawley rats weighing 350-450 grams and aged 8 to 12 weeks were used in the study. Animals were housed 1 animal per cage. Standard environmental conditions (relative humidity of 60 ± 5% and a temperature of 25 ± 3 °C) were maintained in the animal room, with a 12 hour light/dark cycle for the animals. Animals were given food and water freely during the experimental period. Animal handling and housing were performed in accordance with good laboratory practice. Animals were acclimatized for one week. Rats were assigned to three groups. Animals were divided into three groups. Group 1 served as the control group; Group 2 was the study group, in which a known New Neuronal Growth factor (NNGF) was used; and Group 3 used an Angiogenesis Factor (AF). Animals were subjected to TBI using Marmarou’s weight-drop method, <sup>1</sup> ( Free weight drop of a 450-gm weight falling from a 2-meter height). Once the weight was dropped, oxygen (4 liters O2 per minute) was immediately supplied to the animals using a pressurized cylinder for 2 minutes to avoid respiratory depression. After 48 hours under anesthesia, a partial laminectomy was performed at the lumbar 1st vertebra in 24 animals. In the study group, NNGF (Group 2) and Angiogenesis factor (Group 3) were administered intrathecally at 50 mg/kg body weight in 0.5 ml normal saline, and treatment was continued daily for 7 days. In the control group, 0.5 ml of normal saline was injected. Neurological severity score (NSS), a rating system was used to assess neurological deficits, based on a series of 9 tasks measuring motor function, sensory function, balance, and the time points for assessment done at 2 weeks and 4 weeks. After the assessment, the animals were euthanized 30 days after injury, and brain sections were processed for measurement of lesion volume, hippocampal cell loss, angiogenesis, neurogenesis, and dendritic spine remodeling. <bold>Results</bold> : There were 2 deaths in the control group within 2 days of the incurred injury. At two weeks, the assessment of the 9 tasks of the neurological severity score in the control group was Compared to the control (Group 1: 9.98±2.51), Group 2 and Group 3 had scores of 5.66±1.32 (P = 0.0039, 95% CI: -6.90 to -1.74) and 5.66±1.32 (P = 0.0038, 95% CI: -6.89 to -1.75), respectively. Four weeks before euthanization, the NSS for Group 1 was 9.34±1.76, Group 2 was 3.25±0.63 (P = 0.0001, 95% CI: -6.90 to -1.74), and Group 3 was 3.25±1.32 (P = 0.0001, 95% CI: -8.09 to -4.09). Histological analysis showed minimal healing in the control group, moderate healing in Group 2, and marked healing in Group 3, as demonstrated by H&E and immunohistochemistry stains (APP, NF, GFAP, NeuN, CD68): Group 1 vs Group 2 (P = 0.0111, 95% CI: 0.27 to 1.73), Group 1 vs Group 3 (P = 0.009, 95% CI: 0.84 to 5.16), and Group 2 vs Group 3 (P = 0.004, 95% CI: 1.09 to 2.91). <bold>Conclusions</bold> : Our study convincingly shows that the use of peptides after TBI resulted in moderate to marked improvement in the injured brain, as assessed by neurological and histological assessments. We believe our data provide sufficient evidence of safety and demonstrate efficacy, and are ready for human trials in patients with TBI. </p>