Spinal Reactive Oxygen Species and Oxidative Damage Mediate Chronic Pain in Lame Dairy Cows

Ferulic acid via attenuation of oxidative stress and neuro-immune response utilizes antinociceptive effect in mouse model of formalin test

Introduction

Plenty evidences suggests that neuroinflammation and oxidative stress augmented the neural sensitivity specifying that neuro-immune response is involved in the pathophysiology of pain. Ferulic acid (FA), a natural antioxidant found in various fruits, has various pharmacological properties. The purpose of the current study was to assess the antinociceptive effect of FA in a mouse model of formalin test with focus on its anti-neuroinflammatory and antioxidative stress effects.

Methods

The injection of FA (40 mg/kg), piroxicam (2 mg/kg), and saline (0.9% NaCl) (1 ml/kg) was done intraperitoneally and after one hour, formalin injected into the plantar surface of the hind paw of mice. Then pain behavior was documented during 60 min. Then mice were euthanized and prefrontal cortex (PFC) samples were taken. Malondialdehyde (MDA) level, antioxidant capacity and expression of inflammatory genes, counting tumor necrosis factor (TNF-) and interleukine 1 (IL-1) evaluated in the PFC.

Results

exhibited that FA declined the pain behavior following injection of formalin. Besides, FA significantly diminished the MDA level and increased the antioxidant capacity in the PFC. We revealed that FA diminished the expression of TNF-α and IL-1β genes in the PFC.

Conclusion

We conclude that FA exerted antinociceptive effects in the formalin test in mice, at least partially, by reducing oxidative stress and neuroimmune response in the PFC.

Evaluated periodontal tissues and oxidative stress in rats with neuropathic pain-like behavior

BACKGROUND

Oxidative stress has a critical effect on both persistent pain states and periodontal disease. Voltage-gated sodium NaV1.7 (SCN9A), and transient receptor potential ankyrin 1 (TRPA1) are pain genes. The goal of this study was to investigate oxidative stress markers, periodontal status, SCN9A, and TRPA1 channel expression in periodontal tissues of rats with paclitaxel-induced neuropathic pain-like behavior (NPLB).

METHODS AND RESULTS

Totally 16 male Sprague Dawley rats were used: control (n = 8) and paclitaxel-induced pain (PTX) (n = 8). The alveolar bone loss and 8-hydroxy-2-deoxyguanosine (8-OHdG) levels were analyzed histometrically and immunohistochemically. Gingival superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities (spectrophotometric assay) were measured. The relative TRPA1 and SCN9A genes expression levels were evaluated using quantitative real-time PCR (qPCR) in the tissues of gingiva and brain. The PTX group had significantly higher alveolar bone loss and 8-OHdG compared to the control. The PTX group had significantly lower gingival SOD, GPx and CAT activity than the control groups. The PTX group had significantly higher relative gene expression of SCN9A (p = 0.0002) and TRPA1 (p = 0.0002) than the control in gingival tissues. Increased nociceptive susceptibility may affect the increase in oxidative stress and periodontal destruction.

CONCLUSIONS

Chronic pain conditions may increase TRPA1 and SCN9A gene expression in the periodontium. The data of the current study may help develop novel approaches both to maintain periodontal health and alleviate pain in patients suffering from orofacial pain.

Non-Invasive Biomarkers in Saliva and Eye Infrared Thermography to Assess the Stress Response of Calves during Transport

Animal transport is currently a stressful procedure. Therefore, animal-based indicators are needed for reliable and non-invasive welfare assessment. Saliva is a biospecimen with potential validity for the determination of cortisol and oxidative stress, although its use to assess calf welfare during transport has never been tested. Similarly, the applicability and reliability of infrared thermography to assess temperature change during calves' transport have never been evaluated. These objectives were outlined following the known and growing need to identify non-invasive methodologies for stress assessment in bovines. This study was conducted on 20 calves of the Arouquesa autochthone breed, at about nine months of age, during their transport to slaughter. For each animal, saliva samples and thermographic images of the eye were collected at three time points: before transport, after transport, and at slaughter. The saliva was then processed to measure cortisol levels and oxidative stress parameters (reactive oxygen species, thiobarbituric acid reactive substance, carbonyls, and advanced oxidation protein products), and the images were analyzed using FLIR Tools+ software. There was an increase in cortisol concentration and oxidative stress parameters (reactive oxygen species, thiobarbituric acid reactive substance, carbonyls, and advanced oxidation protein products) in saliva after transport. An increase in eye temperature triggered by transport was also observed. The cortisol and eye temperature results at slaughter were returned to values similar to those before transport; however, the values of oxidative stress remained increased (mainly TBARS values). These non-invasive techniques seem to be reliable indicators of stress in bovine transport, and oxidative stress parameters in saliva may be a persistent marker for welfare assessment.

Changes in Dynamic Thiol/Disulfide Homeostasis, and Substance P, B-Endorphin and α-Tocopherol Concentrations in the Spinal Cord of Chronically Lame Dairy Cows

Initial lameness inflammation leads to chronic lameness and development of chronic pain due to the release of pro-inflammatory mediators such as reactive oxygen species (ROS), which are implicated in the transition from acute to chronic pain, and free radical scavengers countering thiol, substance P (SP), and β-endorphin (BE). The present study aimed to evaluate the dynamic thiol-disulfide homeostasis, α-tocopherol concentrations and SP and BE concentrations in the spinal cord of chronically lame dairy cows. Ten lame and 10 non-lame cows with a parity range of 2-6 were selected for the study. Lame cows had a history of up to 3 months of lameness. Spinal cord samples were obtained from the L2 to L4 lumbar vertebrae aspect of each animal. A thiol-disulfide homeostasis assay was performed using absorbance, and the α-tocopherol concentration was determined by HPLC. SP and BE concentrations were measured using ELISA kits. The results indicated that SP and BE were significantly higher in the spinal cord of lame cows. In contrast, disulfide levels and α-tocopherol concentrations were significantly lower in the spinal cord of lame cows. In conclusion, disulfide levels and α-tocopherol concentrations indicated a defective antioxidant response in cows with chronic lameness. The results of SP and BE concentrations suggested chronic pain and a defective endogenous analgesic response.

Animal welfare in Latin America: Trends and characteristics of scientific publications

The present study constitutes a review of the scientific articles about animal welfare in terrestrial farmed animals, published in 19 countries of Latin America. The main objectives were to quantify and characterize articles produced between 1992 and 2021 in farm animals' welfare using "Web of Science [v.5.32]" and "CAB Abstracts" databases. A total of 663 articles were found for the period analyzed, which were mainly in English (87%). The countries with the most publications were Brazil (43%), México (25%), Chile (12%), Uruguay (10%), Colombia (4%) and Argentina (2%). Cattle was the farm species most considered in the publications (41%), and the studies addressed mostly the on-farm production stage (76%). There was a rapid increase in the number of articles published in the last 15 years, accounting for 95% of the publications. This could be related to the publication of welfare standards by the World Organization for Animal Health (WOAH) since 2005, the creation of the Collaborating Center for Animal Welfare and Sustainable Livestock Systems-Chile-Uruguay-México in 2009, a Regional Strategy of Animal Welfare prompted by the WOAH in 2012 and the inclusion of animal welfare in the veterinary curriculum. The fact that most articles were in English shows that Latin American researchers have somehow overcome the challenge of publishing in a non-native language and their research can be read/cited worldwide. However considerable gaps in scientific productivity were identified in comparison to European and North American countries. Scientific research concerning the livestock industry in Latin America faces new challenges arising from the need to move toward more sustainable production systems within the One Welfare and One Health frame.

Potential benefits of melatonin to control pain in ventilated preterm newborns: An updated review

Infants admitted to neonatal intensive care units are repeatedly stimulated by painful events, especially if intubated. Preterm infants are known to have greater pain perception than full term infants due to immaturity of descending inhibitory circuits and poor noxious inhibitory modulation. Newborns exposed to repetitive painful stimuli are at high risk of impairments in brain development and cognition. Chronic pain is induced and supported by proinflammatory cytokines, free radicals, and reactive oxygen species creating a self‐ sustaining vicious circle. Melatonin is a neurohormone secreted by the pineal gland with antioxidant and anti‐inflammatory functions. This review describes the in‐depth beneficial effects of melatonin for pain control in ventilated preterm newborns. As yet, a minimal amount of literature has been undertaken to consider all its promising bioactivities. The rationale behind the use of melatonin for pain control has also been taken into account in this review. Besides, this review addresses safety concerns and dosages. The potential benefits of melatonin have been assessed against neurological disorders, respiratory distress, microbial infections, and as analgesic adjuvant during ventilation. Additionally, a possible approach for the use of melatonin in ventilated newborns will be discussed.

DNA Damage as a Potential Non-Invasive Indicator of Welfare: A Preliminary Study in Zoo-Housed Grizzly Bears (Ursus arctos horribilis)

Measures of oxidative stress have potential for integrating positive and negative life experiences into comprehensive cellular indicators of animal welfare. We explored this possibility when three adult grizzly bear brothers at the Detroit Zoo were temporarily moved to a smaller habitat while their primary home was expanded. We expected that the spatial compression and construction activity might be sources of stress. We observed increased social play and other affiliative behavior in the smaller habitat, and we used daily fecal samples (17 to 24 per bear) to examine whether concentrations of fecal glucocorticoid metabolites (FGM) and 8-hydroxy-2′-deoxyguanosine (8-OHdG, a by-product of DNA damage) were correlated with social behavior. Our overall aim was to explore 8-OHdG as a potential indicator of welfare based on the prediction that 8-OHdG would be lower when more positive social interactions occurred. Concentrations of fecal 8-OHdG increased significantly with higher FGM concentrations, supporting a potential relationship between adrenal activity and rates of DNA damage. However, we found that on days when they engaged in higher rates of affiliative interactions, there were trends for 8-OHdG concentrations to increase for one bear and decrease for another, and no relationship for the third bear. These preliminary results should be interpreted with caution, but suggest a potential relationship between social behavior and 8-OHdG that is modulated by health, personality, or other individual factors. Further validation research is needed, but 8-OHdG may have promise as a non-invasive, cumulative indicator of animal welfare.

Effect of reactive oxygen species of the psoas major muscle in complete Freund's adjuvant-induced inflammatory pain in rats

Lower limb pain is a common clinical disease that affects millions of people worldwide. It is found in previous studies that reactive oxygen species is closely related to neuropathic, cancer, chemotherapy, and inflammatory pain, which can be relieved by reactive oxygen species scavengers. Furthermore, acupuncture or electroacupuncture on the psoas major muscle has a great effect on adjuvant-induced arthritis and lower back pain. In our study, we investigated the function of reactive oxygen species scavengers locally injecting into the ipsilateral psoas major muscle on complete Freund’s adjuvant-induced inflammatory pain. Our results demonstrated that in the development of complete Freund’s adjuvant-induced inflammatory pain, early local continuous application of N-tert-Butyl-α-phenylnitrone (PBN, 1 and 5 mg/kg/0.2 ml) on the ipsilateral psoas major muscle effectively reduced mechanical and cold hyperalgesia. However, intraperitoneal injection of PBN (1 and 5 mg/kg) or local injection of PBN (1 and 5 mg/kg/0.2 ml) into contralateral psoas major muscle, ipsilateral quadratus lumborum, and ipsilateral erector spinae showed limited effect. In the developed inflammatory pain model, local injection of PBN into the ipsilateral psoas major muscle also alleviated pain and paw edema. In addition, reactive oxygen species level increased in ipsilateral psoas major muscle at seven days after complete Freund’s adjuvant injection. In general, PBN reduces complete Freund’s adjuvant-evoked inflammatory pain by inhibiting reactive oxygen species in the psoas major muscle.

Intracerebroventricular injection of propranolol blocked analgesic and neuroprotective effects of resveratrol following L5 spinal nerve ligation in rat

OBJECTIVES

Resveratrol as a natural polyphenolic agent can alleviate neuropathic pain symptoms. The mechanism of analgesic activity of resveratrol is far from clear. The current study examine whether analgesic activity of resveratrol is mediated by its neuroprotective and anti-oxidant activity in the neuropathic pain. We further examine whether analgesic activity of resveratrol is mediated by β-adrenoceptors in the brain.

METHODS

Neuropathic pain induced by L₅ spinal nerve ligation (SNL). Male Wistar rats assigned into sham, SNL, SNL + resveratrol (40 μg/5 μL), and SNL + resveratrol + propranolol (a non-selective β-adrenoceptor antagonist, 30 μg/5 μL) groups. Drugs injected intracerebroventricular (ICV) at day SNL surgery and daily for 6 days following SNL. Thermal allodynia and anxiety examined on days of -1, 2, 4, and 6 following SNL. Electrophysiological study performed on day 6 following SNL for evaluation of resveratrol effects on sciatic nerve conduction velocity (NCV). The activity of catalase (Cat) and superoxide dismutase (SOD) enzymes in the brain assessed on days 6 following SNL.

RESULTS

Resveratrol significantly decreased thermal allodynia (and not anxiety) in all experimental days. Additionally, resveratrol significantly increased NCV, and also normalized the disrupted Cat and SOD activities following neuropathic pain. Furthermore, propranolol significantly blocked the analgesic and neuroprotective effects of resveratrol.

CONCLUSIONS

It is suggested that the analgesic effects of resveratrol is mediated by its neuroprotective and antioxidant activities in the neuropathic rats. Furthermore, propranolol blocked the analgesic and neuroprotective effects of resveratrol.

The antioxidant N-(2-mercaptopropionyl)-glycine (tiopronin) attenuates expression of neuropathic allodynia and hyperalgesia

The current pharmacotherapy of neuropathic pain is inadequate as neuropathic pain involves varied clinical manifestations with multifactorial etiology, modulated by a cascade of physical and molecular events leading to different clinical presentations of pain. There is an accumulating evidence of the involvement of oxidative stress in neuropathy, and antioxidants have shown promise in mitigating neuropathic pain syndromes. To explore the evidence supporting this beneficial proclivity of antioxidants, this study investigated the antinociceptive effectiveness of N-(2-mercaptopropionyl)glycine or tiopronin, a well-recognized aminothiol antioxidant, in a refined chronic constriction injury (CCI) rat model of neuropathic pain. Tiopronin (10, 30, and 90 mg/kg, i.p.) and pregabalin (30 mg/kg, i.p.) were administered daily after CCI surgery. The neuropathic paradigms of mechanical/cold allodynia and mechanical/heat hyperalgesia were assessed on days 3, 7, 14, and 21 post-nerve ligation. At the end of study, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels were estimated in the sciatic nerve, dorsal root ganglion, and spinal cord for assessing the extent of oxidative stress. The expression of neuropathic nociception was attenuated by tiopronin which was observed as a significant attenuation of CCI-induced allodynia and hyperalgesia. Tiopronin reversed the neuronal oxidative stress by significantly reducing MDA, and increasing SOD, CAT, and GSH levels. Pregabalin also showed similar beneficial propensity on CCI-induced neuropathic aberrations. These findings suggest prospective neuropathic pain attenuating efficacy of tiopronin and further corroborated the notion that antioxidants are effective in mitigating the development and expression of neuropathic pain and underlying neuronal oxidative stress.

Antinociceptive, anti-inflammatory and antioxidant effects of Boerhavia coccinea extracts and fractions on acute and persistent inflammatory pain models

Background Boerhavia coccinea (Nyctaginaceae) is an herbaceous plant used for the treatment of pain. The aim of this study was to evaluate the antinociceptive and anti-inflammatory activities of the aqueous (AEBC) and ethanol (EEBC) extracts of Boerhavia coccinea as well as the major fractions (F1, F2 and F3) from EEBC. Methods The antinociceptive effect of the extracts and fractions was evaluated using formalin test. AEBC, EEBC and F1 were selected and further evaluated acutely (24 h) and chronically (16 days) in Complete Freund's Adjuvant (CFA)-induced persistent inflammatory pain for their antihyperalgesic and anti-inflammatory effects. They were administered orally (100 and 200 mg/kg/day) from 48 h following the intraplantar injection of 100 µL of CFA. After the 16 days of chronic treatment, rats' spinal cord and brain were collected for the evaluation of oxidative stress parameters namely nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT). Results AEBC, EEBC and F1 significantly inhibited the first and second phases of the formalin-induced pain. They significantly reduced the hyperalgesia both in acute and chronic treatments. These extracts showed no acute anti-inflammatory effect. AEBC and EEBC exhibited anti-inflammatory activities after repeated administration. AEBC, EEBC and F1 significantly reduced MDA level and significantly increased SOD and catalase activities, mainly in the spinal cord. AEBC and EEBC also reduced the NO production in the spinal cord. Conclusions Boerhavia coccinea extracts and F1 possess potent antinociceptive activity which is not related to their anti-inflammatory properties. Their antioxidant effects may contribute to these activities in chronic treatment.

Surgical castration versus chemical castration in donkeys: response of stress, lipid profile and redox potential biomarkers

Background

Castration is a husbandry practice raising important questions on the welfare and physiological status of farm animals. Searching for effective castration methods that minimally compromise the body physiology is worthy of attention. Therefore, this study aimed to evaluate the differential response of biological systems in donkeys to surgical castration versus the chemical one by CaCl₂ with special emphasis on stress, lipid profile, and oxidative stress biomarkers. Donkeys were divided randomly and equally into two groups; the chemical (Ch) and surgical (S) groups (n = 6). The Ch group was chemically castrated by intratesticular injection of 20% CaCl₂ dissolved in absolute ethanol. Blood samples were collected prior to castration and at 15, 30, 45, and 60 days after the beginning of experiment.

Results

Surprisingly, the Ch group at the end of the experiment was characterized by significantly higher cortisol level compared to the S group. TC and LDL-C levels in the S group significantly decreased at day 45, while TG levels significantly increased at days 45 and 60 in comparison with day 0. HDL-C levels at days 30 and 60 in the Ch group significantly increased in comparison with day 0. At day 30 post-castration, HDL-C was significantly higher and LDL-C was significantly lower in the Ch group than the S group. A significant elevation in TC and LDL-C was observed at day 45 and in HDL-C at the end of experimental duration in the Ch group when compared with the S group. TPX level was significantly lower and TAC was significantly higher in the Ch group at day 45 than the S group.

Conclusion

Surgical castration evoked less stress and minor changes in lipid profile and oxidant/antioxidant balance relative to chemical castration by intratesticular 20% CaCl₂ dissolved in absolute ethanol.