Introduction: Inappropriate and excess vitamin supplementation, particularly for vitamin A, is increasingly recognized as a public health problem in developed countries. On the other hand, blind supplementation of vit...Introduction: Inappropriate and excess vitamin supplementation, particularly for vitamin A, is increasingly recognized as a public health problem in developed countries. On the other hand, blind supplementation of vitamin A, for children in developing countries is a subject of controversy in the literature. The crucial role of vitamin A in the process of spermatogenesis in adult rodents is well established, but only a few publications are consecrated to the long-term effect of vitamin A intake at a young age on testicular development and differentiation. Objectives: Our study aimed to evaluate the long-term effects of acute supplementation at an early age, in the post-natal period, on spermatogenesis and testicular trophicity at adult age. Material and Methods: Young Wistar Albinos rats of 22 days received an acute high dose of supplementation of vitamin A (retinyl palmitate). The control group, group 1, received only extra virgin olive oil, Group 2 a dose of 7000 IU/kg of retinyl palmitate, group 3, 14,000 IU/kg, and Group 4 a dose of 28,000 IU/kg. At 10 weeks of age, the testes’ testosterone levels were measured by ELISA. For histological assessment, sections were stained with Hematoxylin eosin, and the Johnsen score was used to evaluate spermatogenesis in the seminiferous tubules. Results: The average testicular weights of rats were significantly lower in group 4 (p < 0.05), and so was the testosterone level in the testis compared to the control group (p .01). Most of the seminiferous tubules were concerned by an arrest of spermatogenesis and the Johnsen score was decreased with a mean score of 5.96 ± 1.60 (p .001) in that Group. In Group 3, Johnsen’s score was significantly better than the one obtained with the control. Conclusion: We observed a negative effect in the long term with a high acute dose of supplementation of retinyl palmitate at a young age, on testicular development and differentiation. Despite a return to normal diet after that supplementation, during childhood, impaired spermatogenesis w展开更多
Retinyl palmitate(RP) is a derivative of Vitamin A and widely applied as the active component in the fields of cosmetic and pharmaceutics.RP can easily lose its physiological activity under UV irradiation due to its p...Retinyl palmitate(RP) is a derivative of Vitamin A and widely applied as the active component in the fields of cosmetic and pharmaceutics.RP can easily lose its physiological activity under UV irradiation due to its photosensitivity.In this work,it was found that the activity of RP remained 75% after 80 min of UVA irradiation when RP was entrapped in supramolecular gels formed by self-assembly of sorbitol-based gelators.By contrast,the activity of RP in conventional hydroxyethyl cellulose gels only remained 10% under the same conditions.These results showed that the supramolecular gels exhibited a significant protective effect on the photostability of RP.UV spectra of RP in supramolecular gels and corresponding solutions showed no distinct differences,indicating no change of the physicochemical properties of RP.The images of field-emission scanning electron microscopy and fluorescent optical microscopy suggested that the protection by supramolecular gels on the photostability of RP may be attributed to the three-dimensional network structure formed by the self-assembly of the gelators,which reduced the molecular collisions and the degradation process of the photoactivated RP.The present results showed that this protection can be influenced by the structures and the concentration of gelators as well as by the solvent composition.展开更多
文摘Introduction: Inappropriate and excess vitamin supplementation, particularly for vitamin A, is increasingly recognized as a public health problem in developed countries. On the other hand, blind supplementation of vitamin A, for children in developing countries is a subject of controversy in the literature. The crucial role of vitamin A in the process of spermatogenesis in adult rodents is well established, but only a few publications are consecrated to the long-term effect of vitamin A intake at a young age on testicular development and differentiation. Objectives: Our study aimed to evaluate the long-term effects of acute supplementation at an early age, in the post-natal period, on spermatogenesis and testicular trophicity at adult age. Material and Methods: Young Wistar Albinos rats of 22 days received an acute high dose of supplementation of vitamin A (retinyl palmitate). The control group, group 1, received only extra virgin olive oil, Group 2 a dose of 7000 IU/kg of retinyl palmitate, group 3, 14,000 IU/kg, and Group 4 a dose of 28,000 IU/kg. At 10 weeks of age, the testes’ testosterone levels were measured by ELISA. For histological assessment, sections were stained with Hematoxylin eosin, and the Johnsen score was used to evaluate spermatogenesis in the seminiferous tubules. Results: The average testicular weights of rats were significantly lower in group 4 (p < 0.05), and so was the testosterone level in the testis compared to the control group (p .01). Most of the seminiferous tubules were concerned by an arrest of spermatogenesis and the Johnsen score was decreased with a mean score of 5.96 ± 1.60 (p .001) in that Group. In Group 3, Johnsen’s score was significantly better than the one obtained with the control. Conclusion: We observed a negative effect in the long term with a high acute dose of supplementation of retinyl palmitate at a young age, on testicular development and differentiation. Despite a return to normal diet after that supplementation, during childhood, impaired spermatogenesis w
基金supported by the National Natural Science Foundation of China (51073062)the National Basic Research Program of China (2012CB812500)
文摘Retinyl palmitate(RP) is a derivative of Vitamin A and widely applied as the active component in the fields of cosmetic and pharmaceutics.RP can easily lose its physiological activity under UV irradiation due to its photosensitivity.In this work,it was found that the activity of RP remained 75% after 80 min of UVA irradiation when RP was entrapped in supramolecular gels formed by self-assembly of sorbitol-based gelators.By contrast,the activity of RP in conventional hydroxyethyl cellulose gels only remained 10% under the same conditions.These results showed that the supramolecular gels exhibited a significant protective effect on the photostability of RP.UV spectra of RP in supramolecular gels and corresponding solutions showed no distinct differences,indicating no change of the physicochemical properties of RP.The images of field-emission scanning electron microscopy and fluorescent optical microscopy suggested that the protection by supramolecular gels on the photostability of RP may be attributed to the three-dimensional network structure formed by the self-assembly of the gelators,which reduced the molecular collisions and the degradation process of the photoactivated RP.The present results showed that this protection can be influenced by the structures and the concentration of gelators as well as by the solvent composition.
