Protective effect of curcumin on N-nitrosodiethylamine and carbon tetrachloride-induced hepatocarcinogenesis in Sprague–Dawley rats

Curcumin, the yellow spice derived from the roots (rhizomes) of the plant Curcuma longa, has been reported to have a chemoprotective effect against several neoplasms. The protective effect of curcumin during N-nitrosodiethylamine- and carbon tetrachloride-induced hepatocarcinogenesis in Sprague–Dawley rats and its effect on the expression of IkappaB-alpha mRNA were evaluated. Sixty male rats were randomly assigned into four experimental groups. Group A animals received a single i.p. injection of N-nitrosodiethylamine (200 mg/kg b.w.). After 1 week, the animals received weekly s.c. injections of carbon tetrachloride (3 ml/kg b.w./week) for 6 weeks. Group B was given diet containing 0.2 % curcumin 2 weeks before the injection of N-nitrosodiethylamine and continued throughout the experimental period (20 weeks). Group C was given only a diet containing 0.2 % curcumin for the whole period of the experiment. Group D animals served as control. The level of IkappaB-alpha (IкB-α) mRNA was determined by semiquantitative PCR. Administration of diet containing 0.2 % curcumin, 2 weeks before the injection of N-nitrosodiethylamine and throughout the period of experiment, decreased percentage of preneoplastic foci in hepatic parenchyma and inhibited the development of hepatocellular carcinoma, cholangiofibrosis, and cystic cholangioma in rat liver. Moreover, curcumin administration decreased the number and size of the preneoplastic foci induced by N-nitrosodiethylamine and carbon tetrachloride in the liver. The densitometric analysis of the IкB-α mRNA bands revealed that curcumin administration blocked the decrease of IкB-α mRNA induced by N-nitrosodiethylamine and carbon tetrachloride. These results concluded that curcumin inhibited hepatocarcinogenesis induced by N-nitrosodiethylamine and carbon tetrachloride through blocking IкB-α degradation.     

Immunostimolatory activities of Vigna mungo L. extract in male Sprague–Dawley rats

Vigna mungo L. (Fabaceae) is a popular food legume used in the traditional Indian system of medicine for the treatment of a variety of disease conditions. The objective of the study was to evaluate any immunostimulatory activities of the extract of V. mungo seeds in an animal model. The induction of any immunostimulatory effects were evaluated using measures of sheep red blood cells (SRBC)-induced humoral antibody titer, SRBC-induced delayed-type hypersensitivity (DTH), neutrophil adhesion, and in vivo phagocytosis (via the carbon clearance method) after host treatment with the extract. The results here indicated that primary and secondary antibody titers in the rats were significantly increased by treatment with the V. mungo extract as compared with those noted among rats in a control group. Increases in DTH response, the percentage (%) neutrophil adhesion, and in situ phagocytosis were also observed after treatment with the extract. We summarize that the apparent immunostimulatory effect of the V. mungo seed extract might be attributed to an augmentation of humoral and cell-mediated responses, phagocytosis, and hematopoiesis in the treated rats. The findings in this study suggest that V. mungo seed extract possesses profound immunostimulatory activities. Whether such outcomes are also evidenced by consumption of the intact seeds themselves, as is most likely to be the case with humans, remains to be determined. Nonetheless, the present study provides evidence that could help explain how the traditional use of V. mungo has been successful in the treatment of various disorders in humans.     

Phytoestrogen Effects on Vaginal Microbiocenosis of Sprague–Dawley Rats

Phytoestrogens present in the plants endemic for Chile were studied. The effects of phytoextract [specimen of preparation No. 181 (fraction b)] on target tissues were similar to those of estradiol. The preparation inhibited the stimulatory effect of estradiol on vaginal lactobacilli population.     

Intrastriatal infusion of the Parkinsonian neurotoxin,MPP+, induces damage of striatal cell nuclei in Sprague–Dawley rats

The potent Parkinsonian neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine is known to destroy dopaminergic neurons of the basal ganglia. Its neurotoxically active metabolite, 1-methyl-4-phenyl pyridinium (MPP⁺), has been examined in the present study to verify whether administration of the neurotoxin that depletes about 70% of the striatal dopamine (DA) can cause damage to nuclear components of the cells at the terminal region, the striatum. Unilateral intrastriatal infusion of MPP⁺ (100 and 200 nmol in 4 μl saline) caused a dose-dependent depletion of striatal DA (69 and 92%, respectively), as measured employing HPLC electrochemistry. It also resulted in the loss of tyrosine hydroxylase (TH) immunoreactivity in the striatum and in the perikarya at substantia nigra pars compacta (SNpc) and acetylcholinesterase histoenzymological staining in the striatum. Specific nuclear staining employing Hoechst 33342 and acridine orange revealed distorted and spindle shaped nuclei, and perinuclear positioning of nucleolus, respectively, for the former and latter dyes in several of the cell populations in the ipsilateral striatum compared to the contralateral side. Existence of a widened lateral ventricle at the side that received the neurotoxin, as well as denser cellular population, as compared to the contralateral side under transmission electron microscope evidenced general shrinkage of the striatum. Extensive damage of the nuclei was visible in the cell bodies in the treated side. These results demonstrate non-specific damage extending to the cellular groups including cholinergic neurons in addition to dopaminergic neurons in the striatum to intrastriatal administration of the Parkinsonian neurotoxin, MPP⁺.     

Effects of lifelong exercise training on mammary tumorigenesis induced by MNU in female Sprague–Dawley rats

Breast cancer is the most common malignancy in women worldwide. Several studies have suggested that exercise training may decrease the risk of breast cancer development. This study aimed to evaluate the effects of long-term exercise training on mammary tumorigenesis in an animal model of mammary cancer. Fifty female Sprague–Dawley rats were randomly divided into four groups: MNU sedentary, MNU exercised, control sedentary and control exercised. Animals from MNU groups received an intraperitoneal administration of N-methyl-N-nitrosourea (MNU). Animals were exercised on a treadmill during 35 weeks. When animals were killed, blood samples were collected to determine the hematocrit and to perform the biochemical analysis. Mammary tumors were collected and histologically evaluated; the expression of ERs α and β was evaluated in tumor sections by immunohistochemistry. All survived animals from both MNU groups developed mammary tumors. The number of mammary tumors (p > 0.05) and lesions (p = 0.056) was lower in MNU exercised than in MNU sedentary animals. MNU exercised animals showed lower number of malignant lesions than MNU sedentary animals (p = 0.020). C-reactive protein serum concentration was lower in exercised animals; however, the levels of 17-β estradiol were higher in exercised animals. Tumors from exercised animals exhibited higher expression of ER α than tumors from sedentary animals (p < 0.05). This study analyzes the impact of the longest exercise training protocol on mammary tumorigenesis ever performed. We concluded that the lifelong endurance training has beneficial effects on mammary tumorigenesis in female rats (reduced the inflammation, the number of mammary tumors and lesions, and histological grade of malignancy). Additionally, the mammary tumors from MNU exercised group exhibited higher immunoexpression of ER α that is an indicator of well-differentiated tumors and better response to hormone therapy.     

Prolonged effects of DPP-4 inhibitors on steato-hepatitic changes in Sprague–Dawley rats fed a high-cholesterol diet

Objective

Sitagliptin and other dipeptidyl peptidase (DPP)‐4 inhibitors/gliptins are antidiabetic drugs known to improve lipid profile, and confer anti‐inflammatory and anti‐fibrotic effects, which are independent of their hypoglycemic effects. However, in our previous short-term (35 days) studies, we showed that sitagliptin accentuates the hepato-inflammatory effects of high dietary cholesterol (Cho) in male Sprague–Dawley rats. Since most type 2 diabetics also present with lipid abnormalities and use DPP-4 inhibitors for glucose management, the present study was conducted to assess the impact of sitagliptin during long-term (98 days) feeding of a high Cho diet. An additional component of the present investigation was the inclusion of other gliptins to determine if hepatic steatosis, necro‐inflammation, and fibrosis were specific to sitagliptin or are class effects.

Methods

Adult male Sprague–Dawley rats were fed control or high Cho (2.0%) diets, and gavaged daily (from day 30 through 98) with vehicle or DPP-4 inhibitors (sitagliptin or alogliptin or saxagliptin). On day 99 after a 4 h fast, rats were euthanized. Blood and liver samples were collected to measure lipids and cytokines, and for histopathological evaluation, determination of hepatic lesions (steatosis, necrosis, inflammation, and fibrosis) using specific staining and immunohistochemical methods.

Results

Compared to controls, the high Cho diet produced a robust increase in NASH like phenotype that included increased expression of hepatic (Tnfa, Il1b, and Mcp1) and circulatory (TNFα and IL-1β) markers of inflammation, steatosis, necrosis, fibrosis, and mononuclear cell infiltration. These mononuclear cells were identified as macrophages and T cells, and their recruitment in the liver was facilitated by marked increases in endothelium‐expressed cell adhesion molecules. Importantly, treatment with DPP‐4 inhibitors (3 tested) neither alleviated the pathologic responses induced by high Cho diet nor improved lipid profile.

Conclusions

The potential lipid lowering effects of DPP-4 inhibitors were diminished by high Cho (a significant risk factor for inducing liver damage). The robust inflammatory responses induced by high Cho feeding in long-term experiment were not exacerbated by DPP-4 inhibitors and a consistent hepatic inflammatory environment persisted, implying a prospective physiological adaptation.

     

Excitotoxic lesions to the prefrontal cortex of Sprague–Dawley rats do not impair response matching

Perseveration refers to maladaptive persistence of behavior outside appropriate contexts and despite negative outcomes. In humans, perseveration is a symptom of a variety of psychiatric disorders. In rats, perseveration has been observed in reversal learning tasks following lesions of the prefrontal cortex (PFC). However, the exact nature of the impairment underlying this effect remains unclear. Male Sprague–Dawley rats were trained on a novel reversal task that requires switching between two rewarded options varying in effort (concurrent fixed and progressive ratios) necessary to obtain the reward. Following initial training, bilateral lesions of the dorsal PFC, medial PFC, or orbitofrontal cortex were produced by NMDA infusions. When animals were re-tested post-surgery, no significant impairments were found. These results indicate that, in trained rats, the PFC is not necessary for selecting responses on the basis of favorable effort-to-reward contingencies.     

Subacute toxicity and stability of Soshiho-tang,a traditional herbal formula,in Sprague–Dawley rats

Backgroud

Soshiho-tang (SST, Xiao-chai-hu-tang in Chinese and Sho-saiko-to in Japanese), an oriental herbal formula, is used for treatment of chronic liver diseases. Although many researchers have studied the pharmacological properties of SST, information about its safety and toxicity is limited. Therefore, we evaluated the potential safety of SST in Sprague–Dawley rats over a period of 4-weeks.

Methods

The SST was administered once daily by gavage to male and female rats at doses of 0, 500, 1000 and 2000 mg/kg/day for 4 weeks. We measured the body weight, mortality, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross pathological findings, absolute/relative organ weights and histopathology. In addition, we analyzed the component of SST and measured the stability of its component in SST according to study periods using high performance liquid chromatography.

Results

The SST treatment did not result in any toxicologically significant changes in mortality, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross pathological findings, absolute/relative organ weights and histopathology, except for salivation and reduction in body weight in the 2000 mg/kg/day male group. These findings in the 2000 mg/kg/day male group are considered toxicologically insignificant because they are not accompanied by other pathological findings, including in hematology, serum biochemistry and histopatholgy, and they do not exhibit a dose–response relationship. SST is detected three components including liquiritin, baicalin, and glycyrrhizin. In addition, there were not observed the significant differences among the contents of three components in SST according to storage periods.

Conclusion

These results indicate that SST may be a safe material. Based on these results, the no-observed-adverse-effect level was more than 2000 mg/kg for both genders.

     

Individual differences in cocaine-induced locomotor activity of male Sprague–Dawley rats are not explained by plasma corticosterone levels

Humans differ in their initial response to, and subsequent abuse of, addictive drugs like cocaine. Rodents also exhibit marked individual differences in responsiveness to cocaine. Previously, we classified male Sprague–Dawley rats as either low or high cocaine responders (LCRs or HCRs, respectively), based on their acute low-dose cocaine-induced locomotor activity, and found that with repeated drug exposure LCRs exhibit greater cocaine locomotor sensitization, reward and reinforcement than HCRs. Differential cocaine-induced increases in striatal dopamine help to explain the LCR/HCR phenotypes. Differential levels of stress and/or anxiety could also contribute but have not been explored. Here we measured open-field activity and plasma corticosterone levels both pre- and post-cocaine treatment in LCRs, HCRs, and saline-treated controls. The three groups did not differ in baseline locomotor activity or corticosterone levels. Importantly, LCR/HCR differences in corticosterone levels were also not observed following acute cocaine (10 mg/kg, i.p.), when cocaine induced approximately 3.5-fold greater locomotor activity in HCRs than LCRs. Additionally, there were no LCR/HCR differences in plasma corticosterone levels following 5 days of once-daily cocaine, during which time LCRs developed locomotor sensitization such that their cocaine-induced locomotor activity no longer differed from that of HCRs. Likewise, there were no group activity differences in any of four concentric zones within the open-field chamber. In summary, neither plasma corticosterone levels nor thigmotaxis-type anxiety appears to be a factor that contributes to the observed cocaine-induced LCR/HCR behavioral differences.     

The effect of erythropoietin on endometrial edema during ischemia–reperfusion injury in rats

This experimental study examined the effect of erythropoietin (Epo) in a rat model and particularly in an ischemia–reperfusion protocol. The potential beneficial effect of Epo was studied pathologically using endometrial edema (EE) lesions. Endometrial edema was evaluated 60 min after reperfusion (Groups A and C) and 120 min after reperfusion (Groups B and D) in rats. Epo was administered only in Groups C and D. Epo administration non-significantly increased the EE scores by 0.05 (p = 0.9315). Reperfusion non-significantly increased the EE scores by 0.15 (p = 0.6508). Epo administration and reperfusion together non-significantly increased the EE scores by 0.027 (p = 0.8898). Epo administration, reperfusion, and their interaction reduced the EE scores from significant to non-significant levels. Perhaps a study time longer than 2 h or a higher Epo dose could result in complete resolution of the endometrial edema formed as a result of the ischemia–reperfusion injury in this rat model.     

Comparison of Two Sensitization Paradigms of the Acoustic Startle Response in Wistar and Sprague–Dawley Rats

An increase in general responsiveness after aversive stimulation has provided a most widely accepted and well-understood sensitization paradigm. According to a second paradigm (based on the dual process theory of habituation and sensitization), not only additional aversive stimuli, but also the response-eliciting stimuli themselves, induce sensitization. To relate these two sensitization paradigms, we compared the course of startle response parameters during repetitive acoustic stimulation with the change in startle amplitude after electric footshocks in outbred Wistar and Sprague–Dawley rats. Compared to the Wistar rats used, the Sprague–Dawley rats showed a lower response decrement and a shortened latency during repetitive stimulation, both of which are indicators of increased sensitization by the startle-eliciting stimuli. In addition, the Sprague–Dawley rats also demonstrated a reduced increase in startle amplitude following footshock. This was postulated to be a consequence of the strong sensitization by startle-eliciting stimuli, which interferes with sensitization elicited by footshock. Because our Wistar and Sprague–Dawley rats did not differ in initial startle amplitude, but mainly in susceptibility to sensitization, further comparisons of these genetically different stocks of rats seem to be of potential value in studying differences in fear-motivated behavior.     

Nine Generations of Selection for High and Low Nicotine Intake in Outbred Sprague–Dawley Rats

Previous animal studies have revealed significant involvement of genetics in nicotine intake; however, the extent of the genetic contribution to this behavior has not been well addressed. We report the first study of nine generations of selection for high and low voluntary nicotine intake in outbred Sprague–Dawley rats. Bidirectional mass selection resulted in progressively greater nicotine consumption in the high nicotine-preferring line but no decrease in nicotine intake in the low nicotine-preferring line across generations. Our estimated realized heritability for high voluntary nicotine intake is 0.26 vs close to zero for low voluntary nicotine intake. In contrast, we found no differences between the lines across generations for saccharine intake. These selected lines may provide useful animal models for identifying susceptibility and resistance genes and variants for controlling voluntary nicotine intake in rodents, although we recognize that more generations of selection of these two lines and independent replication of our selection for high and low nicotine-preferring lines are needed.     

Induction of Chronic Subclinical Systemic Inflammation in Sprague–Dawley Rats Stimulated by Intermittent Bolus Injection of Lipopolysaccharide

Archivum Immunologiae et Therapiae Experimentalis - Chronic subclinical systemic inflammation has a key role in stimulating several chronic conditions associated with cardiovascular diseases,...     

Skeletal muscle choristoma in the lung of a female Sprague–Dawley rat: A case report

In this report we describe a choristoma in the lung of a female placebo rat. The lesion was observed microscopically in the central part of the left lung lobe and was characterized by a nodule consisting of well-differentiated skeletal muscle cells. The muscle fibers were haphazardly organized giving the nodule a poorly demarcated border. Choristoma is a very rare lesion.     

Micropatterning–retinoic acid co-control of neuronal cell morphology and neurite outgrowth

Creating physical–biochemical superposed microenvironments optimal for stimulating neurite outgrowth would be beneficial for neuronal regenerative medicine. We investigated potential co-regulatory effects of cell micropatterning and retinoic acid (RA) soluble factor on neuronal cell morphology and neurite outgrowth. Human neuroblastoma (SH-SY5Y) cell patterning sensitivity could be enhanced by poly-l-lysine-g-polyethylene glycol cell-repellent back-filling, enabling cell confinement in lanes as narrow as 5 μm. Cells patterned on narrow (5 and 10 μm) lanes showed preferred nucleus orientation following the patterning direction. These cells also showed high nucleus aspect ratio but constrained nucleus spreading. On the other hand, cells on wide (20 μm and above) lanes showed random nucleus orientation and cell and nucleus sizes similar to those on unpatterned controls. All these changes were generally maintained with or without RA. Confining cells on narrow (5 and 10 μm) lanes, even without RA, significantly enhanced neurite extension relative to unpatterned control, which was further stimulated by RA. Interestingly, cell patterning on 5 and 10 μm lanes without RA produced longer neurites relative to the RA treatment alone case. Our data on the potential interplay between microscale physical cell confinement and RA-soluble stimulation may provide a new, integrative insight on how to trigger neurite/axon formation for neuronal regenerative medicine.     

Effect of methanolic leaf extract of <Emphasis Type="Italic">Telfairia occidentalis</Emphasis> (Hook f.) on vaginal cytology,serum hormonal levels and ovarian histomorphology of female (Sprague—Dawley) albino rats

Telfairia occidentalis is one of the most commonly consumed leafy vegetable and a component of the Nigerian ethnomedical pharmacopoeia. It is used frequently as a hematinic in the treatment of postmenstrual blood loss. This study evaluated the effect of the oral administration of methanolic leaf extract of T. occidentalis on vaginal cytology, serum hormone (progesterone and estrogen) levels, and histomorphology of the ovaries of female albino rat. Fifteen female albino rats were used for the study. They were randomly assigned to three groups of five rats each. The first group (A) served as the untreated control and received distilled water while the second group (B) and third (C) received 200 and 800 mg/kg body weight of the extract respectively for 21 days. Evaluation of vaginal cytology did not show any effect of the extract on the estrous cycle. The group C rats that received the highest dose (800 mg/kg body weight) had a significantly higher (p < 0.05) serum concentration of progesterone during the prestrus and estrus phases and a significant lower (p < 0.05) serum levels of oestrogen during the metestrus and diestrus. Histological examination of ovarian tissues of the different groups did not show obvious abnormalities.     

Effect of mode and schedule of administration on carcinogenic effect of N-methyl-N′-nitro-N-nitrosoguanidine in rats

Laboratory of Methods of Carcinogen Screening, Research Institute of Carcinogenesis, All-Union Oncologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. N. Trapeznikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 109, No. 2, pp. 175–176, February, 1990.     

The effect of treatment with recombinant γ-interferon on adjuvant-induced arthritis in rats

We have investigated the effects of recombinant rat -interferon (rIFN) on adjuvant-induced arthritis (AA). Lewis rats, inoculated in the left hind-paw with adjuvant (day 0), were given 10⁵ U/rat of rIFN daily (days 0 to 20), subcutaneously and intramuscularly on alternate days. rIFN suppressed the secondary phase of swelling of both hind-paw on and after day 18 without influencing the earlier phases, both primary and secondary, of swelling. rIFN also reduced the hind-paw bone lesions, the degree of splenomegaly, and the increase in erythrocyte sedimentation rate and plasma fibrinogen. These results indicate a new aspect of the regulatory role of IFN in chronic inflammation.