Early behavioral changes and quantitative analysis of neuropathological features in murine prion disease: Stereological analysis in the albino Swiss mice model

Behavioral and neuropathological changes have been widely investigated in murine prion disease but stereological based unbiased estimates of key neuropathological features have not been carried out. After injections of ME7 infected (ME7) or normal brain homogenates (NBH) into dorsal CA1 of albino Swiss mice and C57BL6, we assessed behavioral changes on hippocampal-dependent tasks. We also estimated by optical fractionator at 15 and 18 weeks post-injections (w.p.i.) the total number of neurons, reactive astrocytes, activated microglia and perineuronal nets (PN) in the polymorphic layer of dentate gyrus (PolDG), CA1 and septum in albino Swiss mice. On average, early behavioral changes in albino Swiss mice start four weeks later than in C57BL6. Cluster and discriminant analysis of behavioral data in albino Swiss mice revealed that four of nine subjects start to change their behavior at 12 w.p.i. and reach terminal stage at 22 w.p.i and the remaining subjects start at 22 w.p.i. and reach terminal stage at 26 w.p.i. Biotinylated dextran-amine BDA-tracer experiments in mossy fiber pathway confirmed axonal degeneration and stereological data showed that early astrocytosis, microgliosis and reduction in the perineuronal nets are independent of a change in the number of neuronal cell bodies. Statistical analysis revealed that the septal region had greater levels of neuroinflammation and extracellular matrix damage than CA1. This stereological and multivariate analysis at early stages of disease in an outbred model of prion disease provided new insights connecting behavioral changes and neuroinflammation and seems to be important to understand the mechanisms of prion disease progression.Key words: prion disease, optical fractionator, neuropathology, behavioral changes, albino Swiss mice     

Effect of metformin on clastogenic and biochemical changes induced by adriamycin in Swiss albino mice

Diabetes mellitus (DM) is a chronic disease that is characterized by deteriorating glycemic control. The disease is known to be caused by imbalance between reactive oxygen species (ROS) and antioxidant defense systems. Hyperglycemia is commonly observed in a wide variety of diseases, including cancer. Although, therapy against glycemic control, is used in all these diseases, the diabetic cancer patients are on additional therapy with anticancer drugs. The objective of present study was to study if Glucophage (metformin), a very popular antidiabetic agent can avert the mutagenicity and lipid peroxidation caused by adriamycin (ADR), which is a commonly used cytotoxic drug. The experimental protocol included oral treatment of mice with different doses (62.5, 125 and 250 mg/kg day) of metformin for 7 days. Some mice in each group were injected i.p. with ADR (15 mg/kg). In each case animals were killed, 30 or 24, 48 and 72 h after the last treatment and femurs were excised for cytological studies by micronucleus test. Additional experiments on estimation of glutathione (GSH) and malondialdehyde (MDA) were undertaken in blood and serum, respectively. Twenty-four hour after the treatment, blood from each mouse was collected from heart and preserved for analysis. The results obtained revealed that pretreatment with metformin: (i) reduced the ADR-induced frequency of micronuclei without any alteration in its cytotoxicity and (ii) protected against the ADR-induced increase and decrease of MDA and GSH, respectively. The exact mechanism of action is not known, however, the inhibition of ADR-induced clastogenicity and lipid peroxidation by metformin may be attributed to the antioxidant action of the latter. Our results demonstrate that metformin might be useful to avert secondary tumor risk by decreasing the accumulation of free radicals and inhibition of mutagenicity.     

Effect of metformin on clastogenic and biochemical changes induced by adriamycin in Swiss albino mice

Diabetes mellitus (DM) is a chronic disease that is characterized by deteriorating glycemic control. The disease is known to be caused by imbalance between reactive oxygen species (ROS) and antioxidant defense systems. Hyperglycemia is commonly observed in a wide variety of diseases, including cancer. Although, therapy against glycemic control, is used in all these diseases, the diabetic cancer patients are on additional therapy with anticancer drugs. The objective of present study was to study if Glucophage (metformin), a very popular antidiabetic agent can avert the mutagenicity and lipid peroxidation caused by adriamycin (ADR), which is a commonly used cytotoxic drug. The experimental protocol included oral treatment of mice with different doses (62.5, 125 and 250 mg/kg day) of metformin for 7 days. Some mice in each group were injected i.p. with ADR (15 mg/kg). In each case animals were killed, 30 or 24, 48 and 72 h after the last treatment and femurs were excised for cytological studies by micronucleus test. Additional experiments on estimation of glutathione (GSH) and malondialdehyde (MDA) were undertaken in blood and serum, respectively. Twenty-four hour after the treatment, blood from each mouse was collected from heart and preserved for analysis. The results obtained revealed that pretreatment with metformin: (i) reduced the ADR-induced frequency of micronuclei without any alteration in its cytotoxicity and (ii) protected against the ADR-induced increase and decrease of MDA and GSH, respectively. The exact mechanism of action is not known, however, the inhibition of ADR-induced clastogenicity and lipid peroxidation by metformin may be attributed to the antioxidant action of the latter. Our results demonstrate that metformin might be useful to avert secondary tumor risk by decreasing the accumulation of free radicals and inhibition of mutagenicity.     

Effect of sesamol on radiation-induced cytotoxicity in Swiss albino mice

The radio-protective ability of sesamol (SM) at various doses viz., 0, 10, 25, 40, 50, 70 and 100mg/kg bw, administered intraperitoneally 30min prior to 9.5Gy whole-body gamma-irradiation was studied in Swiss albino mice. Radiation toxicity and mortality were observed during a period of 30 days and the percentage mortality was calculated. SM pretreatment with 50mg/kg bw was found to be the most effective dose in maintaining body weight and in reducing the percentage mortality, while 100mg/kg bw was found to be more effective in maintaining the spleen index and in stimulation of endogenous spleen colony-forming units. Pretreatment with SM (50mg/kg bw) in mice irradiated with 15Gy significantly reduced dead, inflammatory, mitotic and goblet cells in irradiated jejunum. SM at 50mg/kg bw also increased crypt cells, maintained villus height, and prevented mucosal erosion. Nuclear enlargement in epithelial cells was found less in SM-treated mice compared with the irradiated control. The radiation-induced decrease in endogenous antioxidant enzymes (GSH, GST, catalase) and the increase in lipid peroxidation were also reduced by pretreatment with SM [50 and 100mg/kg bw] at all monitored post-irradiation intervals. There was no protection at a dose less than 25mg/kg bw.     

Effect of sesamol on radiation-induced cytotoxicity in Swiss albino mice

The radio-protective ability of sesamol (SM) at various doses viz., 0, 10, 25, 40, 50, 70 and 100 mg/kg bw, administered intraperitoneally 30 min prior to 9.5 Gy whole-body γ-irradiation was studied in Swiss albino mice. Radiation toxicity and mortality were observed during a period of 30 days and the percentage mortality was calculated. SM pretreatment with 50 mg/kg bw was found to be the most effective dose in maintaining body weight and in reducing the percentage mortality, while 100 mg/kg bw was found to be more effective in maintaining the spleen index and in stimulation of endogenous spleen colony-forming units. Pretreatment with SM (50 mg/kg bw) in mice irradiated with 15 Gy significantly reduced dead, inflammatory, mitotic and goblet cells in irradiated jejunum. SM at 50 mg/kg bw also increased crypt cells, maintained villus height, and prevented mucosal erosion. Nuclear enlargement in epithelial cells was found less in SM-treated mice compared with the irradiated control. The radiation-induced decrease in endogenous antioxidant enzymes (GSH, GST, catalase) and the increase in lipid peroxidation were also reduced by pretreatment with SM [50 and 100 mg/kg bw] at all monitored post-irradiation intervals. There was no protection at a dose less than 25 mg/kg bw.     

Allethrin-induced genotoxicity and oxidative stress in Swiss albino mice

Allethrin (C(19)H(26)O(3)) is non-cyano-containing pyrethroid insecticide that is used extensively for controlling flies and mosquitoes. Apart from its neurotoxic effects in non-target species, allethrin is reported to be mutagenic in bacterial systems. In this study, we observed oxidative damage-mediated genotoxicity caused by allethrin in Swiss albino mice. The genotoxic potential of allethrin was evaluated using chromosome aberrations (CAs) and a micronuclei (MN) induction assay as genetic end-points. The oral intubation of allethrin (25 and 50mg/kg b.wt.) significantly induces CAs and MN in mouse bone marrow cells. The DNA-damaging potential of allethrin was estimated in mouse liver using the DNA alkaline unwinding assay (DAUA) and by measuring the levels of 8-hydroxy-2'-deoxy-guanosine (8-OH-dG). Furthermore, a dose-dependent increase in reactive oxygen species (ROS) generation and lipid peroxidation (LPO), with a concurrent decrease in superoxide dismutase (SOD) and catalase, confirm its pro-oxidant potential. The DNA-damaging potential of allethrin was found to be mediated through the modulation of p53, p21, GADD45α and MDM-2. These results confirm the genotoxic and the pro-oxidant potential of allethrin in Swiss albino mice.     

Inhibition of adriamycin-induced micronuclei by desferrioxamine in Swiss albino mice

Swiss albino male mice, 6–8 weeks old, were treated i.p. with different doses of desferrioxamine dissolved in water for 7 days. Some of the mice in each group were injected i.p. with adriamycin (15 mg/kg) and killed after 30 or 24, 48 and 72 h. The femoral cells of mice in different groups were collected and studied. Desferrioxamine treatment failed to affect the incidence of micronuclei at doses of 125–250 mg/kg/day. Pretreatment with desferrioxamine was found to provide significant protection against adriamycin-induced micronuclei without interfering with its cytotoxic potential.     

Occurrence of priapism after transient right MCAO in Swiss albino mice

Introduction: There are few reports about sexual problems in animal models after stroke. The aim of this paper is to report the occurrence of priapism after right MCAO in Swiss albino mice. In addition, we compared neurological score and apoptosis between the priapism-affected and unaffected mice.

Methods: Swiss albino mice were subjected to 45?min’ MCAO and 7?days’ reperfusion. Mice were observed before MCAO, then daily for 7?days to assess priapism. Neurological status and apoptosis (TUNEL assay) were assessed and compared in priapism and non-priapism mice.

Results: The results showed that the incidence of priapism after MCAO in Swiss albino mice were 65%. Priapism was detectable often at day 2 after stroke. Priapism-affected group had more severe behavioural deficits after stroke compared to non-priapism stroke mice.

Conclusion: Priapism after right MCAO is not rare in albino mice and could be considered as a marker of stroke severity. Further studies are needed to assess the incidence of priapism after stroke in other animal species used for stroke studies such as rat.     

Motor behavioral and neuropathological deficits in mice deficient for normal prion protein expression

It has been difficult to reconcile the absence of pathology and apparently normal behavior of mice lacking prion protein (PrP), referred to as Prnp(0/0) mice, with a mechanism of prion pathogenesis involving progressive loss of PrP(C)-mediated neuroprotection. However, here we report that Prnp(0/0) mice exhibit significant age-related defects in motor coordination and balance compared with mice expressing wild type Prnp on a syngeneic background, and that the brains of behaviorally-impaired Prnp(0/0) mice display the cardinal neuropathological hallmarks of spongiform pathology and reactive astrocytic gliosis that normally accompany prion disease. Consistent with the appearance of cerebellar ataxia as an early symptom in patients with Gerstmann-Str?ussler-Scheinker syndrome (GSS), an inherited form of human prion disease, motor coordination and balance defects manifested in a transgenic (Tg) mouse model of GSS considerably earlier than the onset of end-stage neurodegenerative disease. Our results are consistent with a mechanism in which loss of normal PrP(C) function is an important pathological component of prion diseases.     

Tissue specific and variable collagen proliferation in Swiss albino mice treated with clenbuterol

Chronic administration of clenbuterol, a beta-adrenoceptor agonist (2 mg/kg body weight/day for 30 days) to mice resulted in an increased body mass. Measurement of dry tissue mass suggested a protein anabolic effect in the gastrocnemius and heart. Quantitative estimation of collagen content, a non-contractile element as calculated from hydroxyproline assay revealed its proliferation in the gastrocnemius, cardiac ventricle, intestine and to some extent also in the kidney. Clenbuterol did not induce collagen proliferation in non-muscle tissues such as the lungs and liver. Histopathological examination of sections from treated ventricles showed an extensive collagen infiltration in the subendocardium and at myonecrosis sites.     

Orungo virus: organ distribution with histopathology and development of experimentally infected Swiss albino mice

The organ distribution and pathogenecity of Orungo virus were studied in Swiss Albino mice following intracerebral and intraperitoneal inoculations. There was an age-related response in mice to Orungo virus ic infection. Virus multiplied to higher titres in the brain of newborn (2-day-old) mice than in the other organs. The histopathologic changes which were restricted to the brain included diffuse mononuclear cell infiltration, prominent perivascular and interstitial oedema in the cerebrum and cerebellum. In 10-day-old mice, low level infective virus was detected only in the brain, with resultant mild and focal mononuclear cell infiltration in the cerebral cortex. Recovery from Orungo virus ic infection in 10-day-old animals is accompanied by stunted growth. Orungo virus did not multiply in 21-day-old mice which were found to be histologically unremarkable. Following ip inoculation Orungo virus did not multiply, nor was there an histopathological change in inoculated newborn, 10-day or 21-day-old mice.     

Mutagenic profiles of carbazole in the male germ cells of Swiss albino mice

Mutagenic effect of carbazole was evaluated by employing dominant lethal mutation and sperm head abnormality assays in male Swiss albino mice. For the dominant lethal mutation assay, adult male mice were treated for five consecutive days either with 30 or 60 mg/kg body weight (b.w.) of carbazole by single intraperitoneal (i.p.) injection. For the sperm head abnormality assay mice were treated with 50, 100, 150, 200 and 300 mg/kg b.w as a single i.p. injection. Treatment of adult male mice with carbazole resulted in induction of dominant lethal mutation and abnormal sperm heads. The results show that carbazole is mutagenic in male germ cells of mice.     

Chemomodulatory effect of Dolichos biflorus Linn. on skin and forestomach papillomagenesis in Swiss albino mice

Effect of consumption of three different doses (2%, 4% and 6%, w/w) of Dolichos biflorus Linn. seeds on hepatic drug metabolizing enzymes, antioxidant enzymes, reduced glutathione content, lactate dehydrogenase and lipid peroxidation in Swiss albino mice has been reported. Anti-carcinogenic effect has been studied by 7,12-dimethylbenzanthracene (DMBA)-induced skin and benzo(a)pyrene[B(a)P]-induced forestomach papillomagenesis models. D. biflorus consumption resulted in a significant increase in hepatic carcinogen metabolizing enzyme systems especially at 4% and 6% doses. Significant increase in reduced glutathione content (GSH) and specific activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glutathione reductase (GR) in liver of mice, at 4% and 6% doses has been reported. Lactate dehydrogensae (LDH) activity and peroxidative damage has been significantly decreased at 4% and 6% doses. In skin papillomagenesis model, 4% and 6% dose in diet significantly reduced the tumor incidence (up to 25%), tumor multiplicity (up to 59%) and tumor volume per mouse (up to 70%) as compared to DMBA treated group. Importantly, significant reduction in tumor incidence (up to 33%) and tumor multiplicity (up to 61%) was evident for forestomach papillomagenesis model.     

Effect of glutathione on mitomycin C-induced micronuclei in bone marrow erythrocytes of Swiss albino mice

The antimutagenic potential of glutathione (GSH) on mitomycin C (MMC)-induced micronuclei was evaluated in Swiss albino mice using the in vivo bone marrow micronucleus test. Six groups of animals were maintained simultaneously. The first group received distilled water only, the second group of animals received 2 mg/kg MMC and the third group was administered 4 doses of GSH, i.e., 20, 40, 80 and 160 mg/kg. The fourth group of animals received GSH and MMC simultaneously. The fifth and sixth groups received a cumulative dose of GSH followed by MMC after 24 h. The fifth group of animals were killed 6 h after the administration of MMC, while the sixth group were killed 24 h after the administration of MMC. The results clearly show a statistically significant increase in micronuclei in MMC-treated animals and also in animals that received GSH followed by MMC. However, there was a decrease in micronuclei in animals that received GSH and MMC simultaneously. The results clearly indicate that GSH exhibits an antimutagenic property in the presence of MMC. It is also observed the treatment with GSH prior to MMC does have some protective effect.