Effect of various physical stress models on serum cortisol level in wistar rats

Chronic ecologically relevant stress effects on reverse-translated touchscreen assays of reward responsivity and attentional processes in male rats: Implications for depression

Stagnation in the development of novel therapeutic strategies for treatment-resistant depression has encouraged continued interest in improving preclinical methods. One tactic prioritizes the reverse translation of behavioral tasks developed to objectively quantify depressive phenotypes in patient populations for their use in laboratory animals via touchscreen technology. After cross-species concordance in task outcomes under healthy conditions is confirmed, construct validity can be further enhanced by identifying environmental stressors that reliably produce deficits in task performance that resemble those in depressive participants. The present studies characterized in male rats the ability of two chronic ecologically relevant stressors, inescapable ice water or isolated restraint, to produce depressive-like behavioral phenotypes in the Probabilistic Reward Task (PRT) and Psychomotor Vigilance Task (PVT). These tasks previously have been reverse-translated using touchscreen technology for rodents and nonhuman primates to objectively quantify, respectively, reward responsivity (anhedonia) and attentional processes (impaired cognitive function), each of which are core features of major depressive disorder. In the PRT, both inescapable ice water and isolated restraint produced persistent anhedonic phenotypes compared to non-stressed control performance (i.e., significantly blunted response bias for the richly rewarded stimulus). In the PVT, both chronic stressors impaired attentional processing, revealed by increases in titrated reaction times; however, these deficits largely subsided by the end of the chronic condition. Taken together, these findings confirm the ability of reverse-translated touchscreen tasks to effectively generate behavioral phenotypes that exhibit expected deficits in performance outcomes following exposure to chronic ecologically relevant stress. In turn, this approach is well positioned to appraise the ability of candidate therapeutics to attenuate or reverse such behavioral deficits and, thereby, contribute to preclinical medications development for treatment-resistant depression.

Seed extract of Thai Mucuna pruriens reduced male reproductive damage in rats induced by chronic stress

CONTEXT

Thai Mucuna pruriens (L.) DC. var. pruriens (Fabaceae) (TMP) is known to enrich reproduction but preventive effects on stress related adverse reproductive parameters are not documented.

OBJECTIVE

This study investigates the protective property of TMP seed extract on reproductive damage under chronic stress (CS).

MATERIALS AND METHODS

Male Sprague-Dawley rats were divided into four groups. The control and CS groups received distilled water, whereas the pre-treated rats received the aqueous TMP seed extract at doses of 150 and 300 mg/kg BW for 20 days before co-treatments with CS induction (immobilization and forced swimming) for 81 days. Serum was used to determine the cortisol and testosterone levels. Histology of testis and epididymis was observed with localization of androgen receptor (AR). Sperm parameters and the expression of steroidogenic acute regulatory (StAR), cytochrome P450 family 11 subfamily a member 1 (CYP11A1), AR, HSP70, caspases (3 and 9) and tyrosine phosphorylation (TyrPho) proteins were investigated.

RESULTS

TMP extract improved cortisol level (0.84 ± 0.02 µg/dL) and protected against the damage of reproductive tissues and sperm parameters (count [49.78 ± 3.74 million sperm/mL], viability [90.01 ± 1.17%] and precocious acrosome reaction [1.38 ± 0.48%]). Expression of testicular StAR, CYP11A1, AR and HSP70 proteins was improved. Caspase expression was decreased in treated rats. TMP increased AR expression in CS sperm. Moreover, TyrPho protein expression was corrected after TMP administration.

CONCLUSIONS

TMP seed protected against adverse reproductive parameters in CS via improvements of functionally testicular markers and reductions of apoptotic proteins. It is possible to develop the TMP beans as an alternative medicine in treating of male subfertility caused by CS.

The Preventive Role of Spirulina Platensis (Arthrospira Platensis) in Immune and Oxidative Insults in a Stress-induced Rat Model

Introduction

There is a balance between oxidative stress, antioxidant capacity and immune response. Their roles in physiological and behavioural mechanisms are important for the maintenance of the organism's internal equilibrium. This study aimed to evaluate the antioxidant effects of the exogenous alga Spirulina platensis (Arthrospira platensis) in a stress-induced rat model, and to describe its possible mechanism of action.

Material and Methods

Thirty-six adult male Sprague Dawley rats were separated into four groups: control (C), stress (S), S. platensis (Sp), and S. platensis + stress (SpS). The rats in groups Sp and SpS were fed with 1,500 mg/kg b.w./day Spirulina platensis for 28 days. All rats were exposed to prolonged light phase conditions (18 h light : 6 h dark) for 14 days. The SpS and S groups were exposed to stress by being kept isolated and in a crowded environment. Blood samples were obtained by puncturing the heart on the 28th day. The effect of stress on serum corticosterone, oxidative stress markers (TOS, TAC, PON1, OSI) and immunological parameters (IL-2, IL-4, IFN-ɣ) were tested. Also, the brain, heart, intestines (duodenum, ileum, and colon), kidney, liver, spleen, and stomach of the rats were weighed.

Results

Serum corticosterone levels were higher in the S group than in the C group, and significantly lower in the SpS group than in the S group. Mean total antioxidant capacity were lower in the S group than in the C group, and Spirulina reversed this change. Although not significantly different, IL-2 was lower in the S group than in the C group. However, in the SpS group, IL-2 increased due to Spirulina platensis mitigating effects of stress.

Conclusion

Male rats fed a diet with Spirulina platensis could experience significantly milder physiological changes during stress, although stress patterns may be different. Exogenous antioxidant supplements merit further investigation in animals and humans where the endogenous defence mechanism against stress may not be sufficient.

The Effect of Aerobic Physical Activity in Adrenaline Level in White Laboratory Rats

Introduction

Physical activity is one important factor in the nervous system of animals, it may affect the structure also the function of the brain. Regular aerobic exercises have a good effect on the whole body and thus improves the sense of well-being.

Aim

The aim of this experiment was to evaluate the effect of aerobic physical activity in white laboratory rats for 21 days.

Methods

The experimental animals used were twenty Wistar rats, divided into 2 groups of 10 animals they were subjected to forced swim test for 21 days for 60-90 min swim. The evaluation of levels of Adrenaline was performed on 1st, 7th, 14th day and on the last day of the experiment day 21 using ELISA kit protocol, also body mass was compared between groups.

Results

Our results showed that inducing aerobic physical activity for 21 days on the rats affects their levels of adrenaline. Comparatively, the control group of rats had significantly higher levels of adrenalin compared with day 21 (p=0.435) but lower compared with day 7 and 14 (p=0.231). There was also a difference in body mass which demonstrates adaptability to the surroundings and better coping with physical stress.

Conclusion

Regular aerobic activity for 21 days, for 60-90 min swim has a positive impact on adrenaline level also this aerobic exercise protocol could have a positive impact on reducing and maintaining body weight, thus preventing overweight.

Prostate cancer cell growth characteristics in serum and prostate-conditioned media from moderate-intensity exercise-trained healthy and tumor-bearing rats

Physical activity is associated with diminished risk of several cancers, and preclinical studies suggest exercise training may alter tumor cell growth in certain tissue(s) (e.g., adipose). From moderate-intensity exercise-trained rats versus sedentary controls, we hypothesized 1) there will be a decreased prostate cancer cell viability and migration in vitro and, within the prostate, a reduced 5α-reductase 2 (5αR2) and increased caspase-3 expression, and 2) that exercise training in tumor-bearing (TB) animals will demonstrate a reduced tumor cell viability in prostate-conditioned media. Serum and prostate were harvested from sedentary or exercise-trained (treadmill running, 10-11 weeks) immune-competent (Copenhagen; n = 20) and -deficient (Nude; n = 18) rats. AT-1 and PC-3 prostate cancer cells were grown in one or more of the following: serum-supplemented media (SSM), SSM from TB rats (SSM-TB), prostate-conditioned media (PCM) or PCM from TB rats (PCM-TB) for 24-96 h under normoxic (18.6% O₂) or hypoxic (5% O₂) conditions. Under normoxic condition, there was a decreased AT-1 cell viability in SSM and PCM from the exercise-trained (ET) immune-competent rats, but no difference in PC-3 cell viability in SSM and PCM from ET Nude rats versus the sedentary (SED) group, or in SSM-TB from ET-TB Nude rats versus the SED-TB group. However, there was a decreased PC-3 cell viability in the PCM-TB of the ET-TB group versus SED-TB group. PC-3 cell viability in all conditioned media types was not altered between groups with hypoxia. In the prostate, exercise training did not alter 5αR2 expression levels, but increased caspase-3 expression levels. In conclusion, prior exercise status reduced prostate cancer cell viability in the serum and prostate of trained rats but did not modify several other key prostate tumor cell growth characteristics (e.g., migration, cell cycle except in S phase of PC-3 cells in PCM-TB). Importantly, once the tumor was established, exercise training reduced tumor cell viability in the surrounding prostate, which may help explain the reduced severity of the disease in patients that exercise.

The role of neuropeptide-Y in nandrolone decanoate-induced attenuation of antidepressant effect of exercise

Since the increased prevalence of anabolic androgenic steroids abuse in last few decades is usually accompanied by various exercise protocols, the scope of our study was to evaluate the effects of chronic nandrolone decanoate administration in supraphysiological dose and a prolonged swimming protocol (alone and simultaneously with nandrolone decanoate) on depressive state in male rats. Simultaneously, we investigated the possible alterations in neuropeptide Y (NPY) content in blood and the hippocampus, in order to determine the role of NPY in the modulation of depressive-like behavior.Exercise induced antidepressant effects in tail suspension test (decrease of the total duration of immobility), as well as significant increase in the number of hippocampal NPY-interneurons in CA1 region. Chronic nandrolone decanoate treatment attenuated the beneficial antidepressant effects of exercise as measured by the tail suspension test parameters. Simultaneously, nandrolone decanoate treatment resulted in diminution of NPY content both in blood (decreased serum levels) and in hippocampus (the significant decrease in NPY expression in all three investigated hippocampal regions-CA1, CA2/3 and DG). Our findings indicate that alterations in serum and hippocampal NPY contents may underlie the changes in depressive state in rats. The exercise was beneficial as it exerted antidepressant effect, while chronic nandrolone decanoate treatment resulted in depressive-like behavior. Furthermore, the behavioral indicators of depression showed strong correlations with the serum levels and the hippocampal content of NPY.

Effects of Pulsed Electromagnetic Field with Predatory Stress on Functional and Histological Index of Injured-Sciatic Nerve in Rat

OBJECTIVE

To assess the effect of combination of pulsed electromagnetic fields (PEMF) with predatory stress on transected sciatic nerve regeneration in rats.

METHODS

In sham- operated group (SOG) the nerve was manipulated and left intact. The 10-mm rat sciatic nerve gap was created in rats. In transected group (Transected) nerve stumps were sutured to adjacent muscle and in vein graft group (VG) the gap was bridged using an inside-out vein graft. In VG/PEMF group the transected nerve was bridged using vein graft, phosphate buffered saline was administered into the graft and the whole body was exposed to PEMF. In VG/PS group the transected nerve was bridged using vein graft, phosphate buffered saline was administered into the graft and the rats underwent predatory stress (PS).  In VG/PEMF/PS group the transected nerve was bridged using vein graft, phosphate buffered saline was administered into the graft, the whole body was exposed to PEMF and the rats underwent predatory stress. The regenerated nerve fibers were studied within 12 weeks after surgery.

RESULTS

Functional, gastrocnemius muscle mass findings and morphometric indices confirmed faster recovery of regenerated axons in VG/PEMF and VG/PEMF/PS groups compared to those in the other groups (p=0.001). The whole body exposure to PEMF improved functional recovery. Predatory stress did not affect nerve regeneration in the animals undergone predatory stress (p=0.343).

CONCLUSION

Pulsed electromagnetic fields could be considered as an effective, safe and tolerable treatment for peripheral nerve repair in clinical practice.

Osho Dynamic Meditation's Effect on Serum Cortisol Level

INTRODUCTION

Dynamic meditation is one of the most popular active meditation, introduced by an Indian mystic Osho in 1970. This one hour meditation consists of five stages: Deep fast chaotic breathing, catharsis, using a mantra "Hoo", silence, and dancing. A previous study observed that Osho dynamic meditation causes decrease in several psychopathological variables such as aggressive behaviour, anxiety and depression. However, it is not objectively established that the dynamic meditation has an anti-stress effect.

AIM

To find out the effect of Osho dynamic meditation on the serum cortisol levels (cortisol is an indicator of stress) and therefore to observe whether it has any anti-stress effect.

MATERIALS AND METHODS

An experimental study was planned doing the dynamic meditation empty stomach in morning at 6 to 7 am every day for 21 days from 1^st March 2015 to 21^st March 2015 at Lucknow. Twenty healthy volunteers between 20 to 50 years (14 males and 6 females) participated in the study. Serum cortisol level was estimated from the blood samples collected in the morning one day prior (baseline) and post-meditation on the 21^st day of the study. The difference between mean cortisol levels of the baseline and post-meditation groups were tested for significance by applying the paired t-test.

RESULTS

Sixteen volunteers out of the 20 completed the study while four dropped out due to their health and personal reasons. The serum cortisol levels were decreased in all the 16 participants on 21^st day as compared to the baseline levels and the decline in the mean cortisol level was highly significant (p<0.001).

CONCLUSION

The results of the study showed a significant reduction in plasma cortisol levels when the participants were tested after 21 days of meditation; it can be concluded that the Osho dynamic meditation produces anti-stress effects. The mechanism of action could primarily be attributed to the release of repressed emotions and psychological inhibitions and traumas. Thus, dynamic meditation could be recommended for the amelioration of stress and stress related physical and mental disorders. More clinical studies should be done on dynamic meditation to prove its efficacy and become an approved therapy in hospitals.

Effects of voluntary exercise on apoptosis and cortisol after chronic restraint stress in mice

[Purpose]

To determine whether voluntary exercise (wheel running) has the potential of relieving stress.

[Methods]

In this study, restraint stress with or without voluntary wheel running was performed for mice housed in individual cages. A total of 21 ICR male mice were assigned into control (CON), restraint stress with voluntary exercise (RSVE), or restraint stress (RS) without voluntary exercise groups (n = 7 each).

[Results]

No significant difference in body weight increase was found among the three groups, although CON and RS groups had a tendency of having smaller body weight increase compared to the RSVE group. No significant difference in the expression level of liver heat shock protein 70, Bcl-2, or p53 was found among the three groups. However, caspase-3 protein level in RS group was significantly higher than that in the other two groups. Blood cortisol concentration in RS was higher (p < 0.05) than that in RSVE or CON group. It was the lowest (p < 0.05) in the RSVE group.

[Conclusion]

Our findings suggest that apoptosis caused by chronic restraint stress might be suppressed by voluntary exercise in mice.

Effect of Drug Alprazolam on Restrained Stress Induced Alteration of Serum Cortisol and Antioxidant Vitamins (Vitamin C and E) in Male Albino Rats

INTRODUCTION

Stress can cause harmful effects in the body that induce a wide range of biochemical and behavioural changes. As anti-stress drugs are routinely used to combat stress hence study is needed to assess the contraindication of these drugs in the physiological systems.

AIM

To investigate the effect of alprazolam on restrained stress induced alteration of serum cortisol, and antioxidant vitamin levels in male albino rats.

MATERIALS AND METHODS

Adult male albino rats (body weight 175-225g) were divided into four groups of six animals in each. Group I (control), kept undisturbed in the metabolic cage throughout the 42 days experimental period. Group II (stress) rats were kept in a wire mesh restrainer for 6 hr/day for 42 days. Group III (stress+ withdrawal) rats were stressed for 21 days and withdrawal of stress for remaining 21 days (total 42 days). Group IV (stress + alprazolam) rats were only stressed for 21 days and treated with drug alprazolam (5mg/kg body weight, intraperitoneal) in continuation with stress for remaining 21 days (total period is 42 days). At the end of 42 days all the rats were sacrificed and serum cortisol, vitamin C and E levels were estimated.

RESULTS

Group II (stressed) showed a significant increase in serum cortisol level with concomitant decrease of serum vitamin C and E levels. Group III (withdrawal) and Group IV (+alprazolam) rats showed significant reduction of serum cortisol along with subsequent increase of serum vitamin C and E concentrations.

CONCLUSION

Results indicate a possible antioxidant effect of alprazolam on restrained stress induced alteration of serum cortisol and antioxidant vitamin levels.

Effects of Prepubertal Acute Immobilization Stress on Serum Kisspeptin Level and Testis Histology in Rats

Stress has inhibitory effect on HPG axis through increasing cortisol serum level. In this study, the effect of acute prepubertal stress on kisspeptin, which plays essential role in puberty achievement is assessed. To do this experimental study thirty immature healthy male wistar rats of 4 weeks old and without any symptoms of puberty were selected randomly. These rats were divided into three groups, randomly. Two groups were chosen as control and pretest and one as stress (test) group. Immobilization stress was applied for 10 days and serum level of cortisol, testosterone and kisspeptin were measured. Primary and secondary spermatocyte and sertoli cell evaluated and compared among groups. Mean serum level of kisspeptin in pretest group, control group and stress (test) group were 0.0381 ± 0.0079, 91.0500 ± 4.87430 and 15.2156 ± 3.88135 pg mL(-1) respectively. Serum level of kisspeptin had significant differences between three groups (p < 0.001). Acute prepubertal immobilization stress led to decrease in serum level of kisspeptin and testosterone in stress (test) group compared to control groups. Also stress caused a significant decrease in the numbers of secondary spermatocytes of the test group.