Choosing the optimal rat stock as a model for research into pharmacological correction of male sexual dysfunction

The aim of the study is to identify the mechanisms mediating differences in sexual behavior between Sprague Dawley and Wistar rats, in order to choose the optimal stock for research into pharmacological correction of male sexual dysfunction. Materials and Methods. The experiments were carried out on sexually mature male rats of two stocks (Sprague Dawley and Wistar) weighing 350–450 g and aged 3 to 6 months. The comparative study of animal behavior was performed using standard tests for social interaction, locomotor activity, and anxiety level, as well as male mating behavior patterns. In order to determine the role of hypothalamic glycine receptors in the male sexual behavior, pharmacological manipulations of glycine receptor activity during mating with receptive females were conducted via bilateral intracerebral microcannulas implanted in the medial preoptic area (mPOA) of the male rat anterior hypothalamus. Results. The obtained results revealed statistically significant inter-stock differences in sexual behavior at the final consummatory stage of both intact animals and those after pharmacological activation of glycine receptors in the mPOA. The number of anxiety-related grooming patterns in the Open Field test significantly differed between the stocks for both intact animals and those after pharmacological activation of glycine receptors; the observed differences disappeared after the mPOA glycine receptors were blocked. In the Crowley test of social interaction, no significant difference was found between the stocks. Thus, the revealed difference in sexual behavior between Sprague Dawley and Wistar male rats is likely due to the difference in the level of anxiety, which, in turn, may be associated with difference in the mechanisms of glycinergic neurotransmission in the hypothalamic mPOAs of these rats. Conclusion. To study the relationship between the level of anxiety and sexual behavior, the choice of the Wistar rat stock is optimal since the male sexual behavior in this stock is more sensitive to stress than that in Sprague Dawley rats. However, to model male sexual dysfunction not associated with anxiety, the use of Sprague Dawley male rats should be preferred as these animals show more stable sexual behavior, which is less dependent on the level of anxiety

Study of Stimulus-Induced Plasticity in Neural Networks Cultured in Microfluidic Chips

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3D in vitro platform produced by two-photon polymerization for the analysis of neural network formation and function

Zr-Si organic-inorganic scaffolds fabricated by a two-photon polymerization technique were used for the primary culture of mouse embryonic neural cells. We observed that dissociated hippocampal cells adhere to the scaffolds, produce neurites, elongate and differentiate into adult neurons. Neuronal outgrowth and synaptogenesis were confirmed by immunohistochemical staining with antibodies against βIII-Tubulin and synaptophysin. The formation of a functional neural network was assessed by the measurement of spontaneous activity using Ca2+ imaging of dissociated hippocampal cultures grown on Zr-Si scaffolds. The results of this study suggest that two-photon-induced polymerization of organic-inorganic hybrid biomaterials provides a robust model for 3D neuronal tissue engineering studies

Long-term neurological and behavioral results of biodegradable scaffold implantation in mice brain

The aim of the study was to assess the integral outcomes of implantation biocompatible scaffold as the carrier of neural stem cells in the reconstructive surgery of open traumatic brain injury (TBI) by parameters of neurological and cognitive status of the animals in the experiment. Materials and Methods. Adult male C57BL/6 mice were injured with open-skull weight-drop method. 3D hydrogel scaffold based on modified chitosan in complex with hyaluronic acid was transplanted into the lesion cavity 1 week after TBI. Using a variety of behavioral and cognitive tests (modified neurological severity scores (mNSS), open field test as well as novel object recognition and passive avoidance tests) the short-and long-term neurological and memory functions sequelae induced by TBI were assessed. Magnetic resonance imaging was used to visualize the injury site. Results. Significant functional recovery was observed on both the mNSS and open field tests in the scaffold transplantation group compared to the control TBI group. In addition, enhanced improvement of short and long-term memory functions was found 5 months post injury. Magnetic resonance imaging data revealed that the scaffold transplantation result in decreasing of the volume of injury area compared to control TBI group and preventing the disruption of the neural networks of the brain. Conclusion. Taken together, our findings indicated that transplantation of 3D biodegradable scaffold into injury cavity contributed to the preservation of volume in the damaged region in the first months after TBI which in turn led to a better functional recovery in the remote period

Long-term neurological and behavioral results of biodegradable scaffold implantation in mice brain

The aim of the study was to assess the integral outcomes of implantation biocompatible scaffold as the carrier of neural stem cells in the reconstructive surgery of open traumatic brain injury (TBI) by parameters of neurological and cognitive status of the animals in the experiment. Materials and Methods. Adult male C57BL/6 mice were injured with open-skull weight-drop method. 3D hydrogel scaffold based on modified chitosan in complex with hyaluronic acid was transplanted into the lesion cavity 1 week after TBI. Using a variety of behavioral and cognitive tests (modified neurological severity scores (mNSS), open field test as well as novel object recognition and passive avoidance tests) the short-and long-term neurological and memory functions sequelae induced by TBI were assessed. Magnetic resonance imaging was used to visualize the injury site. Results. Significant functional recovery was observed on both the mNSS and open field tests in the scaffold transplantation group compared to the control TBI group. In addition, enhanced improvement of short and long-term memory functions was found 5 months post injury. Magnetic resonance imaging data revealed that the scaffold transplantation result in decreasing of the volume of injury area compared to control TBI group and preventing the disruption of the neural networks of the brain. Conclusion. Taken together, our findings indicated that transplantation of 3D biodegradable scaffold into injury cavity contributed to the preservation of volume in the damaged region in the first months after TBI which in turn led to a better functional recovery in the remote period