Effect of explosive noise on gastrointestinal transit and plasma levels of polypeptide hormones

Acute High Level Noise Exposure Can Cause Physiological Dysfunction in Macaque Monkeys: Insight on the Medical Protection for Special Working Environmental Personnel

The high level noise caused by intense acoustic weapons and blasting is a common source of acute acoustic trauma faced by some special environmental personnel. Studies have shown that high level noise can cause auditory and non-auditory effects. However, there are few reports on the biological effects, especially the non-auditory effects of acute high level noise exposure in simulated special working environments, and the great differences between experimental animals and human beings make it difficult to extrapolate from research conclusions. In this study, macaque monkeys were used to detect the effects of acute high level noise exposure on hearing, cognition, and cardiovascular function. Auditory brainstem response, auditory P300, and electrocardiogram (ECG) of macaque monkeys were measured. Results showed that acute high level noise exposure caused permanent hearing threshold shifts; partial hearing loss which couldn’t recover to normal levels in the detection period; pathological changes in T wave and QRS complexes; and large fluctuations in cognitive ability after exposure, which finally recovered to normal. These alterations may be a combination of effects caused by stress-induced neuroendocrine dysfunction and mechanical damage of auditory organs. To elaborate the exact mechanism, further studies are still needed. Meanwhile, positive measures should be taken to reduce the incidence of acute high level noise injury.

Effect of short-term and long-term traffic noise exposure on the thyroid gland in adult rats: a sexual dimorphic study

OBJECTIVES

Traffic noise, as one of the noise types, is a widespread feature of the urban environments. Traffic noise exposure can lead to hearing loss, hypertension, obesity and ischemic heart diseases. Thyroid hormones involved in the physiological and pathological conditions of the body. Therefore, this study was designed to aim the evaluation of traffic noise effects on thyroid hormones secretion and thyroid tissue structure.

METHODS

Seventy two males and females wistar rats were used in this study. After one week adaptation, they divided randomly into 12 groups; the control, short term (one day) and long term (one, two, three and four weeks) groups. Traffic sound was recorded, adjusted and played (86 dB) for animals. Female rats' cycle estrus was matched. At the end of experiment, the animals were anesthetized and cardiac blood sample was drawn. Thyroid tissue was then removed. Levels of the T3, T4, TSH, corticosterone and H&E staining were measured. p<0.05 considered to be statistically significant.

RESULTS

Findings showed that in the one-day group, T3 levels increased and T3 levels decreased in the long term groups (p<0.05). In the same way, concentration of TSH decreased in the one day, while they increased in the one, two, three and four weeks' groups (p<0.05). Histopathological evaluations showed that in the female and male animals, long-term traffic noise increased the full follicles and decreased empty follicles (p<0.05).

CONCLUSIONS

This study revealed that traffic noise exposure led to increase of T3 plasma concentration and decrement of TSH level, although in the long term, they return to basal status. It may be due to adaptation to traffic noise.

Gut Microbiota, Its Role in Induction of Alzheimer's Disease Pathology, and Possible Therapeutic Interventions: Special Focus on Anthocyanins

The human gut is a safe environment for several microbes that are symbiotic and important for the wellbeing of human health. However, studies on gut microbiota in different animals have suggested that changes in the composition and structure of these microbes may promote gut inflammation by releasing inflammatory cytokines and lipopolysaccharides, gut-wall leakage, and may affect systemic inflammatory and immune mechanisms that are important for the normal functioning of the body. There are many factors that aid in the gut’s dysbiosis and neuroinflammation, including high stress levels, lack of sleep, fatty and processed foods, and the prolonged use of antibiotics. These neurotoxic mechanisms of dysbiosis may increase susceptibility to Alzheimer’s disease (AD) and other neurodegenerative conditions. Therefore, studies have recently been conducted to tackle AD-like conditions by specifically targeting gut microbes that need further elucidation. It was suggested that gut dyshomeostasis may be regulated by using available options, including the use of flavonoids such as anthocyanins, and restriction of the use of high-fatty-acid-containing food. In this review, we summarize the gut microbiota, factors promoting it, and possible therapeutic interventions especially focused on the therapeutic potential of natural dietary polyflavonoid anthocyanins. Our study strongly suggests that gut dysbiosis and systemic inflammation are critically involved in the development of neurodegenerative disorders, and the natural intake of these flavonoids may provide new therapeutic opportunities for preclinical or clinical studies.

Effects of Psychological, Environmental and Physical Stressors on the Gut Microbiota

Stress, a ubiquitous part of daily human life, has varied biological effects which are increasingly recognized as including modulation of commensal microorganisms residing in the gastrointestinal tract, the gut microbiota. In turn, the gut microbiota influences the host stress response and associated sequelae, thereby implicating the gut microbiota as an important mediator of host health. This narrative review aims to summarize evidence concerning the impact of psychological, environmental, and physical stressors on gut microbiota composition and function. The stressors reviewed include psychological stress, circadian disruption, sleep deprivation, environmental extremes (high altitude, heat, and cold), environmental pathogens, toxicants, pollutants, and noise, physical activity, and diet (nutrient composition and food restriction). Stressors were selected for their direct relevance to military personnel, a population that is commonly exposed to these stressors, often at extremes, and in combination. However, the selected stressors are also common, alone or in combination, in some civilian populations. Evidence from preclinical studies collectively indicates that the reviewed stressors alter the composition, function and metabolic activity of the gut microbiota, but that effects vary across stressors, and can include effects that may be beneficial or detrimental to host health. Translation of these findings to humans is largely lacking at present. This gap precludes concluding with certainty that transient or cumulative exposures to psychological, environmental, and physical stressors have any consistent, meaningful impact on the human gut microbiota. However, provocative preclinical evidence highlights a need for translational research aiming to elucidate the impact of stressors on the human gut microbiota, and how the gut microbiota can be manipulated, for example by using nutrition, to mitigate adverse stress responses.

Relationship between occupational noise exposure and the risk factors of cardiovascular disease in China: A meta-analysis

BACKGROUND

At present, occupational noise exposure has become one of the risk factors of occupational workers and attracted serious concerned of most of occupational disease researchers. To assess associations of occupational noise exposure and cardiovascular disease by meta-analysis.

METHODS AND ANALYSIS

Results from primary studies about occupational noise and cardiovascular disease (2000-2017) were retrieved from literatures, which were conducted in China only. Both random and fixed effect model were used to calculate pooled odds ratio (OR) and their corresponding 95% confidence interval (CI). Review Manager and Stata software were used to perform data analysis. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statements.

RESULTS

After applying stringent inclusion and exclusion criteria, 4771 exposures and 3068 controls from 11 primary studies were used to analyze the relationship between occupational noise exposure and cardiovascular disease. The risk of developing high blood pressure for workers exposed to noise is 2.55 times higher than the controls (I = 52%, 95% CI: 1.94-3.36), and electrocardiograph (ECG) abnormality is 2.27 times higher than the control groups (I = 22%, 95% CI: 1.96-2.62). The bias analysis suggested that there is publication bias, but it didn't affect the conclusions from trim test.

CONCLUSION

The impact of high-intensity noise exposure on the worker's cardiovascular system is much greater than that of the unexposed control group, and the effect on hypertension of the exposed group is greater than that of the ECG.

Insect tea attenuates hydrochloric acid and ethanol-induced mice acute gastric injury

The aim of the present study was to investigate the protective effect of insect tea on HCl/ethanol-induced gastric ulcers in ICR mice. The serum levels of vasoactive intestinal peptide, substance P, somatostatin, motilin and endothelin-1 in mice were assessed using commercial kits and gastric tissues of superoxide dismutase (SOD, nitric oxide (NO) and malondialdehyde (MDA) were determined using western blot analysis Insect tea significantly reduced HCl/ethanol-induced gastric juice secretion and increased the pH of gastric juice (P<0.05). Insect tea treatment signfiicantly increased vasoactive intestinal peptide and somatostatin, and significantly decreased motilin, substance P and endothelin levels in the serum (P<0.05). Treatment with insect tea was demonstrated to significantly increase levels of gastric SOD and NO and to reduce levels of MDA in the gastric ulcer mouse model (P<0.05). The gastric expression of inhibitor of nuclear factor-κB (NF-κB), epidermal growth factor (EGF), EGF receptor, neuronal nitric oxide synthase (nNOS), endothelial NOS, Mn-SOD, Cu/Zn-SOD and catalase was significantly increased in mice treated with inset tea compared with untreated model mice (P<0.05). Levels of NF-κB, and inducible NOS were demonstrated to be decreased in mice treated with insect tea compared with untreated model mice (P<0.05). The results of the present study suggest that insect tea has a protective effect against HCl/ethanol-induced gastric ulcers in ICR mice. This effect may be achieved via modulating serum neuropeptide levels, reducing gastric juice secretion, and modulating the inflammation- and antioxidant-associated protein expressions in gastric tissue.

Melatonin Attenuates Noise Stress-induced Gastrointestinal Motility Disorder and Gastric Stress Ulcer: Role of Gastrointestinal Hormones and Oxidative Stress in Rats

BACKGROUND/AIMS

There are increasing evidences for gastrointestinal motility disorder (GIMD) and gastric stress ulcer induced by noise stress. The present study was to investigate the reversed effect of melatonin on GIMD and gastric stress ulcer induced by noise stress and potential mechanism.

METHODS

Noise stress was induced on rats, and melatonin (15 mg/kg) was administered to rats by intraperitoneal injection. Differences were assessed in gastric residual rate (GRR), small intestine propulsion rate (SPR), Guth injury score, cortisol, gastrointestinal hormones (calcitonin-gene-related peptide and motilin) and oxidative stress markers (superoxide dismutase and malondialde hyde) in blood plasma as well as gastric mucosa homogenate with or without melatonin. The pathological examination of gastric mucosa was also performed.

RESULTS

The GRR and SPR were improved by noise stress compared with control (P < 0.05). The pathological examination and Guth injury score revealed gastric stress ulcer. Moreover, the levels of cortisol, motilin and malondialdehyde in blood plasma and ma-londialdehyde in gastric mucosa homogenate were increased by noise stress (P < 0.05). CGRP and superoxide dismutase activ-ity in both of blood plasma and gastric mucosa homogenate were significantly decreased (P< 0.05). Furthermore, melatonin reversed changes in GRR, SPR, pathological examination, Guth injury score, cortisol, motilin, CGRP, superoxide dismutase activity and malondialdehyde (P < 0.05).

CONCLUSIONS

Melatonin is effective in reversing the GIMD and gastric stress ulcer induced by noise stress. The underlying mechanism may be involved in oxidative stress and gastrointestinal hormones.

Effects on neuroendocrinoimmune network of Lizhong Pill in the reserpine induced rats with spleen deficiency in traditional Chinese medicine

AIM OF THE STUDY

Lizhong Pill, composed of radix Ginseng (Panax ginseng C.A. Meyer), rhizoma Zingiberis (Zingiber officinale Roscoe), rhizoma Atractylodis Macrocephalae (Atractylodes macrocephala Koidz.) and radix Glycytthizae (Glycyrrhiza uralensis Fisch.), is a classical herbal product for curing spleen deficiency in traditional Chinese medicine (TCM), and reserpine treated rats show similar signs to TCM spleen deficiency pattern. This paper is aimed to explore the regulatory effect on neuroendocrinoimmune network by Lizhong Pill in reserpine induced TCM spleen deficiency rats.

MATERIALS AND METHODS

100 healthy adult male SD rats, with a mean weight of 200 g, were randomly divided into five groups in average: control group, reserpine treated group, atropine treated group, treatment groups with Lizhong Pill at high dose and low dose (equal to the dosage of crude drugs for 4 g/kg/d and 8 g/kg/d). Rats in reserpine treated group were induced by intraperitoneal injection of reserpine at 0.5 mg/kgd for 4 weeks. The levels of IL-1, IL-6 and gastrin were measured with radioimmunoassay, TNF-α and IFN-γ in serum were measured with ELISA, the level of vasoactive intestinal peptide (VIP) and substance P (SP) in small intestine were determined with radioimmunoassay, and the TNF-α and TGF-β positive cells in small intestine were detected by immunohistological staining. Data were analyzed with SAS 9.1 software package.

RESULTS

The rats in reserpine treated group, body weight, concentrations of IFN-γ, IL-1 and TNF-α in serum, expression of TGF-β in small intestine, VIP in small intestine decreased (P<0.05), and the level of IL-6 in serum, expression of TNF-α, SP in small intestine and gastrin were increased (P<0.05). Administration of Lizhong Pill at high dose could increase the body weights at day 21, and the weights of rats in Lizhong Pill groups were much higher compared to reserpine treated group. At high dose of Lizhong Pill could increase the level of TNF-α in serum. Lizhong Pill at high dose and low dose could reverse the changes of IL-1, IL-6 and IFN-γ, gastrin, expression of TGF-β and TNF-α, VIP and SP in small intestine.

CONCLUSIONS

The rats treated with reserpine, with similar signs to TCM spleen deficiency, show neuroendocrinoimmune disorders, and the restoration of the neuroendocrinoimmune disorders might be the part of mechanism of Lizhong Pill for reinforcing TCM spleen deficiency.