Effect of sugar beet tubers as a partial replacer to green fodder on production performance and economics of lactating Surti buffaloes in lean period.

AIM: The objective of this study was to evaluate the effects of sugar beet tubers as a replacer to green fodder on production performance and economics of lactating Surti buffaloes. MATERIALS AND METHODS: This trial was conducted at the Livestock Research Station, Navsari Agricultural University, Navsari. Twenty lactating Surti buffaloes in a changeover experimental design were selected to assess the effects of replacing green fodder with sugar beet (Beta vulgaris L.) tubers on production performance, economics of feeding sugar beet and blood biochemical profile. Half (50%) of the hybrid Napier was replaced with sliced sugar beet tubers in the ration of experimental animals. RESULTS: Partial replacement of hybrid Napier with that of sugar beet tubers numerically improved dry matter intake, milk yield, 4% fat corrected milk and milk composition parameters such as fat, solid non-fat, protein and lactose, but not significantly. The blood parameters were in normal range and non-significant except that of glucose and triglycerides, which were increased in the sugar beet group. Replacing sugar beet tubers also proved to be cost-effective with improved net profit around Rs. 6.63/day. CONCLUSION: It can be concluded that 50% hybrid Napier fodder can be replaced with sugar beet tubers without any adverse effect on animal production performance, milk composition blood biochemical profile and economics of feeding.

Nicotine and estrogen synergistically exacerbate cerebral ischemic injury.

The greater incidence of myocardial infarction, cardiac arrest, and ischemic stroke among women who smoke and use oral contraception (OC) compared to women who do not smoke and who do or do not use OC may be due in part to how nicotine influences endocrine function in women. For example, we recently demonstrated that chronic exposure to nicotine, the addictive agent in tobacco smoke responsible for the elevated risk of cardiac arrest, abolishes the endogenous or exogenous 17ß-estradiol-conferred protection of the hippocampus against global cerebral ischemia (a potential outcome of cardiac arrest) in naive or ovariectomized female rats. In the current study we examined the hypotheses that (1) a synergistic deleterious effect of nicotine plus oral contraceptives exacerbates post-ischemic hippocampal damage in female rats, and (2) nicotine directly inhibits estrogen-mediated intracellular signaling in the hippocampus. To test first hypothesis and to simulate smoking behavior-induced nicotine levels in the human body, we implanted osmotic pumps containing nicotine in the female rats for 16 days. Furthermore, we mimicked the use of oral contraceptives in females by administering oral contraceptives orally to the rat. Rats exposed to either nicotine alone or in combination with oral contraceptives were subjected to an episode of cerebral ischemia and the resultant brain damage was quantified. These results showed for the first time that nicotine with oral contraceptives did indeed exacerbate post-ischemic CA1 damage as compared to nicotine alone in naive female rats. In ex vivo hippocampal slice cultures, we found that nicotine alone or with 17ß-estradiol directly hinders estrogen receptors-mediated phosphorylation of cyclic-AMP element binding protein, a process required for neuronal survival and also exacerbates ischemic damage. Thus, nicotine can affect the outcome of cerebral ischemia by influencing brain endocrine function directly rather than through indirect systemic effects.

Post-ischemic activation of protein kinase C ε protects the hippocampus from cerebral ischemic injury via alterations in cerebral blood flow.

Protein kinase C (PKC) is a family of serine/threonine-isozymes that are involved in many signaling events in normal and disease states. Previous studies from our lab have demonstrated that ɛPKC plays a pivotal role in neuroprotection induced by ischemic preconditioning. However, the role of ɛPKC during and after brain ischemia is not clearly defined. Therefore, in the present study, we tested the hypothesis that activation of ɛPKC during an ischemic event is neuroprotective. Furthermore, other studies have demonstrated that ɛPKC mediates cerebral ischemic tolerance in the rat brain by decreasing vascular tone. Thus, we also tested the effects of ɛPKC activation during ischemia on cerebral blood flow (CBF). We found that ψɛ-Receptors for Activated C Kinase (RACK), a ɛPKC-selective peptide activator, injected intravenously 30min before induction of global cerebral ischemia conferred neuroprotection in the CA1 region of the rat hippocampus. Moreover, measurements of CBF before, during, and after cerebral ischemia revealed a significant reduction in the reperfusion phase of rats pretreated with ψɛRACK as compared to Tat peptide (vehicle). Our results suggest that ɛPKC can protect the rat brain against ischemic damage by regulating CBF. Thus, ɛPKC may be one of the treatment modalities against ischemic injury.

Forebrain ischemia triggers GABAergic system degeneration in substantia nigra at chronic stages in rats.

The long-term consequences of forebrain ischemia include delayed Parkinson's syndrome. This study revealed delayed neurodegeneration in the substantia nigra 8 weeks after 12.5 minutes of global ischemia in rat brain. Following neuronal loss of 30-40% in central and dorsolateral striatum at day 3, neuronal damage in the substantia nigra (SN) was assessed at 4-8 weeks using immunohistochemistry for glutamate decarboxylase 67 (GAD67), vesicular GABA transporter (VGAT), and calretinin (CR). At day 56, the optical density of GAD67-, but not VGAT-, immunoreactivity in substantia nigra pars reticulata (SNR)-significantly decreased. CR-neurons concentrated in substantia nigra pars compacta (SNC) were reduced by 27% from day 3 (n = 5) to day 56 (n = 7, ANOVA, p < .01). Movement coordination was impaired at day 56, as evaluated using beam-walking test (time-to-traverse 5.6 ± 1.2 sec versus 11.8 ± 5.4 sec; sham versus ischemia, p < .05, n = 5, and 7, resp.). Our results demonstrate delayed impairment of the GABAergic system components in SN and associated with movement deficits after global ischemia.

Derangements of post-ischemic cerebral blood flow by protein kinase C delta.

Cerebral ischemia causes blood flow derangements characterized by hyperemia (increased cerebral blood flow, CBF) and subsequent hypoperfusion (decreased CBF). We previously demonstrated that protein kinase C delta (δPKC) plays an important role in hippocampal neuronal death after ischemia. However, whether part of this protection is due to the role of δPKC on CBF following cerebral ischemia remains poorly understood. We hypothesized that δPKC exacerbates hyperemia and subsequent hypoperfusion resulting in CBF derangements following ischemia. Sprague-Dawley (SD) rats pretreated with a δPKC specific inhibitor (δV1-1, 0.5 mg/kg) exhibited attenuation of hyperemia and latent hypoperfusion characterized by vasoconstriction followed by vasodilation of microvessels after 2-vessel occlusion plus hypotension measured by 2-photon microscopy. In an asphyxial cardiac arrest model (ACA), SD rats treated with δV1-1 (pre- and post-ischemia) exhibited improved perfusion after 24 h and less hippocampal CA1 neuronal death 7 days after ACA. These results suggest possible therapeutic potential of δPKC in modulating CBF and neuronal damage after cerebral ischemia.

Resveratrol pretreatment protects rat brain from cerebral ischemic damage via a sirtuin 1-uncoupling protein 2 pathway.

Resveratrol is a natural polyphenol found in grapes and wine and has been associated with protective effects against cardiovascular diseases. In vitro, both resveratrol preconditioning (RPC) and ischemic preconditioning (IPC) require activation of sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide (NAD(+))-dependent deacetylase, to induce neuroprotection against cerebral ischemia. In the present study, we tested two hypotheses: (a) that neuroprotection against cerebral ischemia can be induced by RPC in vivo; and (b) that RPC neuroprotection involves alterations in mitochondrial function via the SIRT1 target mitochondrial uncoupling protein 2 (UCP2). IPC was induced by 2 min of global ischemia (temporary bilateral carotid artery occlusion with hypotension), and RPC, by i.p. injection of resveratrol at 10, 50 and 100 mg/kg dosages. Forty-eight hours later, we compared the neuroprotective efficacy of RPC and IPC in vulnerable cornu ammonis 1 hippocampal pyramidal neurons using a rat model of asphyxial cardiac arrest (ACA). SIRT1 activity was measured using a SIRT1-specific fluorescent enzyme activity assay. In hippocampal mitochondria isolated 48 h after IPC or RPC, we measured UCP2 levels, membrane potential, respiration, and the mitochondrial ATP synthesis efficiency (ADP/O ratio). Both IPC and RPC induced tolerance against brain injury induced by cardiac arrest in this in vivo model. IPC increased SIRT1 activity at 48 h, while RPC increased SIRT1 activity at 1 h but not 48 h after treatment in hippocampus. Resveratrol significantly decreased UCP2 levels by 35% compared to sham-treated rats. The SIRT1-specific inhibitor sirtinol abolished the neuroprotection afforded by RPC and the decrease in UCP2 levels. Finally, RPC significantly increased the ADP/O ratio in hippocampal mitochondria reflecting enhanced ATP synthesis efficiency. In conclusion, in vivo resveratrol pretreatment confers neuroprotection similar to IPC via the SIRT1-UCP2 pathway.

Pretreatment with a single estradiol-17beta bolus activates cyclic-AMP response element binding protein and protects CA1 neurons against global cerebral ischemia.

Estradiol-17beta is released from the ovaries in a cyclic manner during the normal estrous cycle in rats. During the transition from the diestrous to proestrous stage, the 17beta-estradiol increases in blood circulation. We hypothesized that a higher serum level of endogenous 17beta-estradiol would protect hippocampal pyramidal neurons against global cerebral ischemia via activation of the cyclic-AMP response element binding protein (CREB)-mediated signaling cascade. Furthermore, we asked if a single 17beta-estradiol bolus provides protection against ischemia in the absence of endogenous estradiol. To test these hypotheses, rats were subjected to global cerebral ischemia at different stages of the estrous cycle. Ischemia was produced by bilateral carotid occlusion and systemic hypotension. Brains were examined for histopathology at 7 days of reperfusion. Higher serum levels of 17beta-estradiol (at proestrus and estrus stages) correlated with increased immunoreactivity of pCREB in hippocampus and ischemic tolerance. At diestrus, when circulating gonadal hormone concentrations were lowest, the pCREB protein content of hippocampus was reduced and showed the least number of normal neurons after ischemia compared to other stages of the estrous cycle. A similar phosphorylation pattern was also observed for mitogen-activated protein kinase (MAPK) and calcium-calmodulin-dependent protein kinase (CaMKII) in hippocampus. The cyclic variation in ovarian hormones did not reflect phosphorylation of protein kinase B (Akt). To test the efficacy of a single bolus of 17beta-estradiol before ischemia, ovariectomized rats were treated with 17beta-estradiol (5/10/50 microg/kg) or vehicle (oil) and 48/72/96 h later rats were exposed to cerebral ischemia. A single 17beta-estradiol bolus treatment in ovariectomized rats significantly increased CREB mRNA activation and protected CA1 pyramidal neurons against ischemia. These results suggest that an exogenous bolus of 17beta-estradiol to ovariectomized rats protects hippocampus against ischemia via activation of the CREB pathway in a manner similar to the endogenous estrous cycle.

Ischemic preconditioning via epsilon protein kinase C activation requires cyclooxygenase-2 activation in vitro.

The signaling pathway of cyclooxygenase-2 (COX-2) induction following ischemic preconditioning (IPC) in brain remains undefined. To determine role of COX-2 in ischemic preconditioning, we used two in vitro models: mixed cortical neuron/astrocyte cell cultures and organotypic hippocampal slice cultures. We simulated IPC by exposing cell or slice cultures to 1 h or 15 min of oxygen/glucose deprivation (OGD), respectively, 48 h prior to ischemia. To mimic ischemia in vitro, we exposed cell or slice cultures to OGD of 4 h or 40 min, respectively. In cell cultures, these experiments revealed that COX-2 induction peaked at 24 h following IPC in cell culture. Inhibition of COX-2 activation with 50 microM NS-398 (a COX-2 selective inhibitor) abolished IPC-mediated neuroprotection in both in vitro models. Next, we tested whether epsilon protein kinase C (epsilonPKC) and extracellular signal regulated kinase 1/2 (ERK1/2) activation was involved in IPC-mediated neuroprotection and COX-2 expression in cell culture. Cell cultures were treated with an epsilonPKC-specific activating peptide (psiepsilonRACK, 100 nM) for 1 h, and 48 h later were exposed to OGD. epsilonPKC activation increased ERK1/2 phosphorylation and COX-2 induction and conferred neuroprotection similar to IPC. Additionally, inhibition of either epsilonPKC or ERK1/2 activation abolished COX-2 expression and neuroprotection due to ischemic preconditioning. These results demonstrate a crucial role for the epsilonPKC-->ERK1/2-->COX-2 pathway in the induction of neuroprotection via ischemic preconditioning.

Estrogen preconditioning protects the hippocampal CA1 against ischemia.

Estrogen is neuroprotective against ischemia in both in vivo and in vitro injury models. Because of the promising preclinical data on neuroprotection, the Women's Estrogen for Stroke Trial was initiated. The outcomes from this trial were, however, unsuccessful and questions emerged about the safety of chronic estrogen treatment in women. In contrast to the chronic estrogen treatment strategy, the present study aims to investigate: (1) the neuroprotective efficacy of single estrogen pretreatment/preconditioning; and (2) the existence of a similarity between estrogen- and ischemic preconditioning-induced neuroprotection against cerebral ischemia. The efficacy of estrogen was tested in an in vitro model of cerebral ischemia using hippocampal organotypic slice culture system. The hippocampal organotypic slice cultures were generated from female neonatal (9-11 days old) Sprague-Dawley rats. The slices were exposed to estradiol-17beta (0.5, 1, 5 nM) for various durations (1, 2 or 4 h) 48 h prior to ischemia (40 min of oxygen-glucose deprivation). For ischemic preconditioning, slices were exposed to sublethal oxygen-glucose deprivation (15 min), 48 h prior to lethal oxygen-glucose deprivation. Quantification of cell death in hippocampal CA1 region was conducted by using propidium iodide fluorescence staining technique. Results demonstrated that estrogen preconditioning significantly protects the hippocampal CA1 region against ischemia (P<0.001) and mimicked ischemic preconditioning-induced neuroprotection. The propidium iodide fluorescence values of estrogen preconditioning, ischemic preconditioning and ischemia groups were 21+/-2 (mean+/-S.E.M.) (1 nM; 2 h; n=15), 18+/-2 (5 nM; 4 h; n=12), 32+/-3 (n=8), 65+/-3 (n=27), respectively. Further, estrogen preconditioning initiated a calcium-mediated signaling pathway leading to protection of CA1 neurons against ischemia. Future investigations in estrogen preconditioning may suggest new estrogen regimens that avoid potential side effects of chronic estrogen treatment for stroke patients.

Hyperbaric oxygen therapy protects against mitochondrial dysfunction and delays onset of motor neuron disease in Wobbler mice.

The Wobbler mouse is a model of human motor neuron disease. Recently we reported the impairment of mitochondrial complex IV in Wobbler mouse CNS, including motor cortex and spinal cord. The present study was designed to test the effect of hyperbaric oxygen therapy (HBOT) on (1) mitochondrial functions in young Wobbler mice, and (2) the onset and progression of the disease with aging. HBOT was carried out at 2 atmospheres absolute (2 ATA) oxygen for 1 h/day for 30 days. Control groups consisted of both untreated Wobbler mice and non-diseased Wobbler mice. The rate of respiration for complex IV in mitochondria isolated from motor cortex was improved by 40% (P<0.05) after HBOT. The onset and progression of the disease in the Wobbler mice was studied using litters of pups from proven heterozygous breeding pairs, which were treated from birth with 2 ATA HBOT for 1 h/day 6 days a week for the animals' lifetime. A "blinded" observer examined the onset and progression of the Wobbler phenotype, including walking capabilities ranging from normal walking to jaw walking (unable to use forepaws), and the paw condition (from normal to curled wrists and forelimb fixed to the chest). These data indicate that the onset of disease in untreated Wobbler mice averaged 36+/-4.3 days in terms of walking and 40+/-5.7 days in terms of paw condition. HBOT significantly delayed (P<0.001 for both paw condition and walking) the onset of disease to 59+/-8.2 days (in terms of walking) and 63+/-7.6 days (in terms of paw condition). Our data suggest that HBOT significantly ameliorates mitochondrial dysfunction in the motor cortex and spinal cord and greatly delays the onset of the disease in an animal model of motor neuron disease.

Effect of acute administration of isoproterenol on submandibular salivary gland of female rat.

The functions of salivary glands are under the regulation of both sympathetic as well as parasympathetic nerve fibers. Further, it has also been demonstrated that chronic administration of a beta-adrenergic agonist isoproterenol (IPR) results in hypertrophy and hyperplasia of submandibular gland [Schneyer C A, Am J Physiol, 203 (1962) 232]. Specific purpose of the present attempt was to look for metabolic responses of submandibular gland of oestrous female rats at very short intervals after 10 min of administration of 5, 10 and 15 micrograms of IPR to females in oestrous condition; pharmacological action and clearance time being only 8 min. The results indicated significant reduction in case of enzymic activities of phosphorylase, total ATPase and Na(+)-K+ ATPase. Cyclic AMP-specific phosphodiesterase and succinate dehydrogenase activities were suppressed only with 5 micrograms dose, but with rising dose levels the effect was not so apparent. Protein content of the gland was reduced slightly by administration of IPR. Hence, it became clear that submandibular gland responds rapidly to IPR administration. Implications of these observations are discussed.

Possible significance of anogenital licking by female rat during precopulatory behavioural patterns.

Possible significance of licking of anogenital region by female rat in the initial steps of precopulatory behaviour was studied in short bouts of 3 min each. The order of conspicuous events was--(1) exploratory behaviour, (2) partners pursuing each other, (3) head-to-tail orientation and mutual licking of anogenital regions; particularly when females were in oestrous and metoestrous stages and (4) obvious avoidance and even aggressive behaviour by female during dioestrous stage.

Influence of oestrous cyclicity on certain metabolic alterations in the submandibular glands of female rats.

This report concerns changes brought about in the submandibular salivary gland during different stages of the oestrous cycle in the concentrations of total lipids, cholesterol and protein, together with an assessment of the activities of cyclic AMP-specific phosphodiesterase, ATPase, succinate dehydrogenase and an estimation of plasma glucose concentrations. As it is known that the ovarian steroids influence metabolic processes, it was thought desirable to study such metabolic alterations. During the transition from a dioestrous to oestrous stage, lipid accumulation occurred. However, during the metoestrous stage, catabolic tendencies predominated although there was some protein synthesis.

Influence of oestrous cyclicity on some aspects of carbohydrate metabolism of the submandibular salivary gland of the albino rat.

Titres of oestrogen are known to rise from dioestrous to proestrous stage of the oestrous cycle. Such a rising level of estrogen may be responsible for rise in intracellular concentration of cAMP. The estrogen primed tissue, changing from proestrous to oestrous, under known increasing progesterone level and preovulatory LH surge, may led to a sort of balancing action on the varying levels of glycogen synthetase and phosphorylase enzyme activities so as to play a role in maintaining a steady state of glycogen concentration in the salivary gland. Therefore, alterations in glycogen concentration and the activities of concerned enzymes viz. glycogen synthetase, phosphorylase and cAMP-specific phosphodiesterase (cAMP-PDE) have been studied in albino rats. An abrupt but significant drop in cAMP-specific phosphodiesterase (cAMP-PDE) activity was found to facilitate corresponding reduction in glycogen and lowering protein concentration of the gland, during transition from oestrous to metoestrous. Main features of the meteostrous stage were depletion of glycogen and protein concentration. Taking into consideration the alteration of glandular glycogen and protein concentration, during various stages of oestrous cycle, variation in the viscosity of saliva has been suggested; in phase with the cyclicity.