Effect of Pulicaria mauritanica on Glucose Metabolism and Glycogen Content in Streptozotocin-Induced Diabetic Rats.

AIMS: The study aimed to assess the antihyperglycemic activity of Pulicaria mauritanica. BACKGROUND: Pulicaria mauritanica is a medicinal and aromatic plant used for the treatment of many diseases such as inflammation, diabetes, and intestinal disorders. OBJECTIVE: The main goals of this present paper were to confirm the antihyperglycemic capacity of aqueous extract from Pulicaria mauritanica in normoglycemic and diabetic rats over a period of time (7 days of treatment). METHODS: The effect of the aqueous extract of Pulicaria mauritanica from aerial parts (AEPM) on glucose and lipid metabolism was tested using an acute test (single dose during 6 hours) and subchronic assay (repeated oral administration for seven days) at a dose of 60 mg/kg and the serum glucose levels were measured in normoglycemic and streptozotocin(STZ)-induced diabetic rats. In addition, the glycogen content in the liver, extensor digitorum longus (EDL), and soleus was evaluated. The antioxidant activity, phytochemical screening, and quantification of some secondary metabolites of this extract were also performed. RESULTS: AEPM at a dose of 60 mg/kg reduced the plasma glucose concentrations significantly in STZ-induced diabetic rats after a single oral administration (p<0.05). This lowering effect became more significant during the repeated oral administration in hyperglycemic rats (p<0.0001). Also, the findings showed that this plant exhibited a significant increase in liver and skeletal soleus muscle glycogen content in diabetic rats. AEPM revealed a remarkable antioxidant activity in addition to the presence of polyphenol compounds such as flavonoids, tannins, saponins, sterols, glucides, terpenoids, quinones, anthraquinones, and mucilage. CONCLUSION: The study shows that AEPM exhibits antihyperglycemic activity in diabetic rats, and it increases liver and muscle glycogen content.

Brain glycogen content is increased in the acute and interictal chronic stages of the mouse pilocarpine model of epilepsy.

Glucose is the main brain fuel in fed conditions, while astrocytic glycogen is used as supplemental fuel when the brain is stimulated. Brain glycogen levels are decreased shortly after induced seizures in rodents, but little is known about how glycogen levels are affected interictally in chronic models of epilepsy. Reduced glutamine synthetase activity has been suggested to lead to increased brain glycogen levels in humans with chronic epilepsy. Here, we used the mouse pilocarpine model of epilepsy to investigate whether brain glycogen levels are altered, both acutely and in the chronic stage of the model. One day after pilocarpine-induced convulsive status epilepticus (CSE), glycogen levels were higher in the hippocampal formation, cerebral cortex, and cerebellum. Opposite to expected, this was accompanied by elevated glutamine synthetase activity in the hippocampus but not the cortex. Increased interictal glycogen amounts were seen in the hippocampal formation and cerebral cortex in the chronic stage of the model (21 days post-CSE), suggesting long-lasting alterations in glycogen metabolism. Glycogen solubility in the cerebral cortex was unaltered in this epilepsy mouse model. Glycogen synthase kinase 3 beta (Gsk3b) mRNA levels were reduced in the hippocampal formations of mice in the chronic stage, which may underlie the elevated brain glycogen content in this model. This is the first report of elevated interictal glycogen levels in a chronic epilepsy model. Increased glycogen amounts in the brain may influence seizure susceptibility in this model, and this warrants further investigation.

Biochemical and clinical aspects of glycogen storage diseases.

The synthesis of glycogen represents a key pathway for the disposal of excess glucose while its degradation is crucial for providing energy during exercise and times of need. The importance of glycogen metabolism is also highlighted by human genetic disorders that are caused by mutations in the enzymes involved. In this review, we provide a basic summary on glycogen metabolism and some of the clinical aspects of the classical glycogen storage diseases. Disruptions in glycogen metabolism usually result in some level of dysfunction in the liver, muscle, heart, kidney and/or brain. Furthermore, the spectrum of symptoms observed is very broad, depending on the affected enzyme. Finally, we briefly discuss an aspect of glycogen metabolism related to the maintenance of its structure that seems to be gaining more recent attention. For example, in Lafora progressive myoclonus epilepsy, patients exhibit an accumulation of inclusion bodies in several tissues, containing glycogen with increased phosphorylation, longer chain lengths and irregular branch points. This abnormal structure is thought to make glycogen insoluble and resistant to degradation. Consequently, its accumulation becomes toxic to neurons, leading to cell death. Although the genes responsible have been identified, studies in the past two decades are only beginning to shed light into their molecular functions.

Endometritis, salpingitis and fertilisation rates after mating mares with a history of intrauterine lumenal fluid accumulation.

The occurrence of uterine and oviductal inflammation, and fertilisation rates, were measured on Day 3 post ovulation in inseminated mares that had either exhibited intrauterine lumenal fluid during a previous dioestrus (Experiment 1) or had acute endometritis induced by intrauterine infusion of 1% glycogen (Experiment 2). Endometritis was assessed by uterine cytology and histology whereas oviductal inflammation was measured histologically. Fertilisation rates were calculated from the percentage of cleaved ova recovered by retrograde flushing of the oviducts. Mares with or without pre-existing uterine fluid during dioestrus that were inseminated showed a higher incidence of endometritis than control mares without pre-existing uterine fluid that were not inseminated (n = 7 mares/group). However, inseminated mares with uterine fluid did not show a higher incidence of endometritis than inseminated mares without uterine fluid. Mares with or without pre-existing uterine fluid showed a higher incidence of endometritis than salpingitis and these 2 groups of mares showed equivalent rates of fertilisation and oviductal oocyte recovery. Mares inseminated with semen alone or semen following 1% glycogen treatment had a higher incidence of endometritis than control noninseminated mares (n = 17 mares/group) but mares that received semen plus 1% glycogen did not show a higher incidence of endometritis than mares that received semen alone. Both these groups of mares showed a higher incidence of endometritis than salpingitis and those that received semen plus 1% glycogen showed an equal recovery rate of recently ovulated ova but a lower fertilisation rate than the mares that received semen alone.

Patrón de envejecimiento vascular del ovario postmenopáusico / Vascular againg pattern of post-menopausic ovary

Se ha establecido que los vasos sanguíneos durante la postmenopausia, sufren cambios progresivos que consisten en el engrosamiento de su pared vascular, con la consiguiente disminución del diámetro en su luz, pero se desconoce el material a expensas del cual ocurre dicho engrosamiento vascular, por lo que se analizaron histológicamente y mediante técnicas de coloración especial 70 ovarios, 35 de ellos postmenopáusicos y 35 del ciclo reproductivo. En el ovario postmenopáusico se encontró que las arterias, venas y arteriolas tenían su luz disminuída hasta en 88.5 por ciento. El 95.2 por ciento tenían engrosada su pared vascular a expensas del glucógeno y la colágena la cual se encontró aumentada en 65.7 de lso caos, además de que las fibras elásticas de los vasos sanguíneos estuvieron duplicadas en 52.9 por ciento de los ovarios postmenopáusicos. Esto confirma nuestra hipótesis de que el envejecimiento vascular en el ovario posmenopáusico, comprende el engrosamiento de los vasos sanguíneos a expensa del depósito de glucógeno y colágena, por lo que en consecuencia se observa su luz dismunuída.