Efecto del donepecilo y la cerebrolisina en la neuromorfología y actividad motora del ratón

Abstract

Cognitive decline associated with ageing and age-related disorders emerges as one of the greatest health challenges in the next decades. To date, the molecular mechanisms underlying the onset of neuronal physiological changes in the central nervous system (CNS) remain unclear. Studies have indicated the decline in working memory performance in older adults. Similarly, age-related disorders such as Alzheimer´s disease (AD), are associated with changes in the prefontral cortex and related neural circuitry, wich underlines the decline of integrative function between different brain regions. The basal forebrain cholinergic complex comprising medial septum, horizontal and vertical diagonal band of Broca, and nucleus basalis of Meynert provides the mayor cholinergic projections to the cerebral cortex and hippocampus. The cholinergic neurons of this complex have been assumed to undergo moderate degenerative changes during aging, resulting in cholinergic hypofunction that has related to the progressing memory deficits with aging. Then, we evaluated the effect of combination of cholinergic (donepezil) and neurotrophic (cerebrolysin) on the locomotor activity induced by a novel environment as well the effect on the morphology of neuronal cells from the brain of mayor adult male mouse. The DON is a potent and selective acetylcholinesterase inhibitor used in the treatment of Alzheimer´s disease. CBL is a mixture of neuropeptides with effects similar to the endogenous neurotrophic factors and is considered one of the best drugs used in the treatment of dementias such as Alzheimer´s disease. NIH male mouse of 7 months old were obtained, the animals were grouped and each mouse was assigned to either a vehicle (water and “Tween 80” solution 1:4 (1 ml/100 g of body weight), group donepezil DON (0.1 mg/100 g), group cerebrolysin CBL (0.1 g/100 g), and the combined group DON+CBL (0.1 mg/ 0.1 g/100 g), and was administered daily for 9 weeks i.p. After treatment the locomotor activity induced by a novel environment was assessed in vehicle, DON, CBL, and DON+CBL, immediately after the animals were sacrificed and the brains were removed and stained using a modified "Golgi-Cox" method. Finally slices of the brains were obtained and fixed with synthetic resin. Pyramidal cells from layers III and V of the PFC, from BLA, area CA1 of the dorsal and ventral hippocampus, granule cells from the dentate gyrus, and medium spiny neurons of the Shell and core of NAcc were selected for study. We analyzed each neuron and her density distal spines with "Sholl's analysis" (SA) method. We found that the motor activity was increased in the experimental groups compared to control group, nevertheless we did not find the additive effect in the combined therapy. In the prefrontal cortex layer III the DON monotherapy as well as the CBL monotherapy increased the dendritic branching compared to the control group, besides in the combined group (D+CBL) we find pharmacological additive effect demonstrated by the branching increment compared to the control and monotherapy groups. In the distal spines density both monotherapies as well as the combinated therapy increased the spines density compared to the control group, but without showed differences among them. In the layer V of the prefrontal cortex the branching increased in the experimental groups compared to the control group but without showed differences among them, with the exemption in the second and third order dendritic length only with the combined therapy. In dorsal hippocampus CA1 the DON monotherapy did not modify the branching, however the branching decreased in the CBL and therapy combined groups. The dendritic spine density only increased with the DON monotherapy. In the ventral hippocampus CA1, dentate gyrus, basolateral amygdala, and the shell and core of accumbens nucleus the DON and CBL monotherapies increased the dendritic branching of the same way as the combined therapy also increased the branching but without generating additive effects, a similar effect of the treatments on the spines density in these regions were observed. Cerebrolysin was as effective as donepezil, and the combinacion of neurotrophic (CBL) and cholinergic (DON) treatment was effective only in the prefrontal cortex.