Stress ulceration in rats: impact of prior stress experience

Effect of Huanglian Decoction on the Intestinal Microbiome in Stress Ulcer (SU) Mice

Background

Stress ulcer (SU) is a serious gastrointestinal mucosal lesion under acute stress. Huanglian decoction is a famous traditional Chinese medicine prescription, which has been used to treat digestive system diseases for thousands of years. Many clinical cases have proved that Huanglian decoction has a good effect on SU. Some studies have shown that the intestinal bacteria will be changed accordingly when the gastrointestinal mucosa is damaged. However, there are few published reports on the effect of the intestinal microbiome with SU mice that were treated by Huanglian decoction. In this study, we investigated the effect of the fecal microbiome in mice with SU by the 16S rDNA sequencing technology.

Methods

Male KM mice were induced by cold-restraint stress except for the normal control group and then treated by Huanglian decoction (Group HD) and Esomeprazole magnesium solution (Group ES) separately for 7 days. 16S rDNA sequencing technology analysis was applied to evaluate the changes of bacterial flora in mice feces. And, histopathological methods and molecular biological detection methods were also performed.

Results

Huanglian decoction could help to repair the gastric mucosal injury and regulate the relative content of TNF-α and IL-1β. Moreover, Huanglian decoction could increase the relative abundance of intestinal probiotics in the intestine of mice with SU, especially in Verrucomicrobiae and Akkermansia.

Conclusions

Huanglian decoction might effectively promote the repair of gastrointestinal mucosal injury and regulate the number and species of intestinal bacteria to maintain the stability of gastrointestinal microecology.

Catecholamines, stress, and disease: a psychobiological perspective

OBJECTIVE

Research on the relationship between physiological responses to stressful stimulation and the onset of psychosomatic illnesses has been an area of intense interest for many years. Studies using animal models have contributed significantly to this field of inquiry by taking several complementary approaches.

METHOD

Three specific research strategies taken in our laboratory will be highlighted here. Each involves studies in conscious, freely behaving animals.

RESULTS

Genetically selected animals have been exposed to acute stressors to unmask neuroendocrine and autonomic abnormalities related to disease susceptibility. In addition, studies of aged animals suggest that exaggerated physiological responses to acute stress may underlie some age-related pathologies. Finally, a series of studies has revealed that exposure of laboratory animals to stressful stimulation may exert long-lasting influences on the ways in which these subjects respond in the future to the same or novel stressors.

CONCLUSIONS

These findings illustrate how studies with laboratory animals have the potential for refining the questions that are posed in research with clinical populations and for providing insight into the underlying physiological mechanisms of individual variability in disease susceptibility and the development of appropriate therapeutic interventions.

Prenatal stress attenuates ulceration in the activity stress paradigm

In the present study, 28 pregnant rats were subjected to either light-restraint stress or no manipulation for days 14-21 of the gestational period. At approx. 50 days of age, both male (n = 16) and female (n = 16) prenatally stressed (PS) and control offspring were subjected to the activity stress (AS) paradigm. During this subsequent stress experience, PS rats developed less ulceration than control rats. PS rats also displayed about half the activity of the control animals during the habituation phase of the AS paradigm, prior to the induction of stress. Given this decrease in baseline activity in PS animals, implications of using activity as a measure of emotionality in PS animals are discussed. Several sex differences were also observed; females differed from males in that they 1) exhibited higher activity levels in both the habituation and experimental phases of the AS procedure, 2) developed heavier relative adrenal weights, and 3) reached criteria for sacrifice in fewer days.

Influence of environmental enrichment and sex on predator stress response in rats

Based on sex, rats were randomly assigned to either an enriched or standard environment for 30 days prior to behavioral testing. The predator stress testing consisted of placing the rat in a cat avoidance apparatus so that the rat's behavioral response to a natural stressor, the cat, could be assessed. The rats were subsequently exposed to a partial predator stimulus (cat urine) that was placed in the home cages for 7 days. Each animal was then sacrificed and the stomach, adrenal glands, and thymus gland were removed and assessed. Results indicated that 1) the enriched rats engaged in less defensive behavior than the standard rats during behavioral testing, 2) female rats demonstrated more defensive behavioral patterns compared to male rats, and 3) the enriched environment affected females more than males, as evidenced by the interaction effects on various recorded behaviors.

Restraint stress in biomedical research: an update

Since the publication of our initial review of restraint stress in 1986, much work has continued with this technique, either as a tool for the investigation of other pharmacological, physiological, or pathologic phenomena or with restraint stress itself serving as the object of the study. As we noted in 1986, the major use of restraint has been for the induction of stress responses in animals and, more specifically, for the investigation of drug effects, particularly as they affect typical stress-related pathology--gastrointestinal, neuroendocrine, and immunological agents have been extensively studied. In compiling this update on restraint stress and its effects, we noted an increasing emphasis on central nervous system mechanisms in peripheral disease, especially gastrointestinal disease. In particular, many CNS-active agents have been tested for their effects on gastric and duodenal lesion formation and gastric secretion, including antidepressants, antipsychotics, anxiolytics, noradrenergic, serotonergic, dopaminergic, and peptidergic compounds. Some of these agents are especially active in the gastrointestinal tract even when administered centrally, further solidifying the concept of a brain-gut axis. The present update includes studies of: methods and procedures, pre-restraint manipulations, post-restraint/healing effects, and drug effects. In addition, a current bibliography of reports that have employed restraint is included.

Some psychosomatic causal factors of restraint-in-water stress ulcers

Rats were stressed by 75 min restraint in a tube suspended vertically while dry (19 degrees C) or partially immersed in tanks of water at different temperatures (19, 27, 35 degrees C), either in a conscious state or while under pentobarbital anesthesia. Restraint was followed by 75 min rest in the home cage and then sacrificed under halothane anesthesia. Assessment of the degree of gastric erosion indicated that restraint alone, whether the animal was rendered unconscious or not, was not sufficient to induce ulceration. However, in conscious animals, the addition of partial immersion did induce ulceration that was inversely related to the temperature of the water bath. This effect was not merely the result of brain stem and spinal reflex processes, because unconscious animals exposed to the most severe conditions (19 degrees C) showed no ulceration.

The activity-stress paradigm: possible mechanisms and applications

The mechanisms and applications of the activity-stress (A-S) research paradigm are examined in this article. Past research has reflected the value of this paradigm in the investigation of ulcerogenesis. Evidence is offered to support a theory explaining the excessive running observed in the A-S animals, according to which, animals commence running to increase body temperature after failing to adapt to the restricted feeding regime. Further, excessive running levels are hypothesized to be sustained by reinforcement resulting from increased mesolimbic dopaminergic activity. Finally, parallels between the behavior observed in the A-S animals and some forms of maladaptive behavior observed in humans are discussed.

Parallelism among stress effects on ulcer, immunosuppression and analgesia: commonality of mechanisms?

Some general principles and mechanisms have been discovered that govern proactive effects of one stress on animals' later stress or challenge induced behavior, nociception, immune function, and stomach ulcerations. As described below, these principles demonstrate a considerable degree of parallelism across the domains represented by measures of learning deficits and fear-related behaviors, hypoalgesia, immunological status and stress gastric ulcerations. At a minimum, these parallels suggest that operational factors found important in one domain are likely factors of importance in the other domains. Beyond this, these parallels are permissive of an inference of commonality in underlying processes. Nonetheless, results reviewed below suggest that the specific response of the organism to stress is highly dependent on specific characteristics of the stressor.