Social. Pain. Rat

BACKGROUND AND AIMS: Newborn infants are vulnerable to procedural stress and pain exposure on the first weeks of life that represents a critical period for the development of nociceptive, sensory, emotional, and social functions. We evaluated the nociceptive behavior of adult male and female rats that were submitted to nociceptive experience in the neonatal period and the maternal behavior in the postnatal period. METHODS: The animals were submitted to repetitive needle pricking from the second to the fifteenth postnatal day (PND2-15)...

Nerve injuries often result in neuropathic pain with co-morbid changes in social behaviours, motivation, sleep-wake cycles and neuroendocrine function. In an animal model of neuropathic injury (CCI) similar co-morbid changes are evoked in a subpopulation (~30%) of injured rats. In addition to anatomical evidence of altered neuronal and glial function, the periaqueductal grey (PAG) of these rats shows evidence of cell death. These changes in the PAG may play a role in the disruption of the normal emotional coping responses triggered by nerve injury...

The ventral tegmental area (VTA) is a brain region recently shown to interfere with pain perception. According to previous studies, improvement of antioxidant defense mechanisms reduces pain. The aim of this study was to show that lack of social interaction influences oxidative stress in the VTA and that this results in increased pain tolerance. In this study, 21 male Sprague-Dawley rats were randomly divided into 2 groups: paired and socially isolated (SI). After one week of acclimatization, the SI rats were isolated for 14 days and the other rats were paired for the same period...

Pain can be socially transferred between familiar rats due to empathic responses. To validate rat model of empathy for pain, effects of pain expressions in a cagemate demonstrator (CD) in pain on empathic pain responses in a naïve cagemate observer (CO) after 30 min priming dyadic social interactions (PDSI) were evaluated. The CD rats were prepared with four pain models: bee venom (BV), formalin, complete Freund's adjuvant (CFA), and spared nerve injury (SNI). Both BV and formalin tests are characterized by displayable and eye-identifiable spontaneous pain-related behaviors (SPRB) immediately after treatment, while CFA and SNI models are characterized by delayed occurrence of evoked pain hypersensitivity but with less eye-identifiable SPRB...

Low back pain (LBP) is a common worldwide disease that causes an enormous social economic burden. Intervertebral disc degeneration (IDD) is considered as a major cause of LBP. The process of IDD is complicated and involves both inflammation and senescence. The production of pro-inflammatory cytokines, including tumor necrosis factor (TNF)α and interleukin (IL)-1β, is increased in the degenerating intervertebral disc, inducing extracellular matrix degradation. Urolithin A (UA) is a metabolite compound resulting from the degradation of ellagitannins by gut bacteria...

BACKGROUND: Infant nerve injury causes delayed adolescent neuropathic pain, but whether it also leads to psychiatric illness is unknown. Environmental enrichment (EE) increases social communication and activity. Thus, our goal was to test anxiety- and depression-like behaviors after infant peripheral nerve injury and evaluate the effect of environmental enrichment on these models of affective disorders. METHODS: Open field, elevated plus maze, sucrose preference, and pain behaviors (paw withdrawal threshold, spontaneous guarding score, and cold response to acetone) were measured in rats that received infant spared nerve injury (SNI)...

Oxytocin (OT), known for its neurohormonal effects around birth, has recently been suggested for being a critical determinant in neurodevelopmental disorders. This hypothalamic neuropeptide exerts a potent analgesic effect through an action on the nociceptive system. This endogenous control of pain has an important adaptive value but might be altered by early life stress, possibly contributing to its long-term consequences on pain responses and associated comorbidities. We tested this hypothesis using a rat model of neonatal maternal separation (NMS) known to induce long-term consequences on several brain functions including chronic stress, anxiety, altered social behavior, and visceral hypersensitivity...

The cumulative and match/mismatch hypotheses of stress are still under discussion regarding the effects of early life stress (ELS) on the vulnerability or resilience to psychopathology. In this context, an additional stress in later life (second hit) often leads to stress-related disorders that frequently include comorbid pain states. We previously observed that maternal separation (MS), a model of ELS, reduces vulnerability to neuropathic and inflammatory pain in rats. In the present study, we investigated the effects of an additional later stressor on the vulnerability to inflammatory pain...

After peri-adolescence isolation rearing (IS) and subchronic ketamine (KET) treatment, adult, selectively bred Wistar rats (named WISKET) mimic abnormal behaviors reminiscent of human schizophrenia, including reduced prepulse-inhibition of startle reflex, disturbances in cognition, locomotor activity and thermoregulation, decreased pain sensitivity and electrophysiological alterations. To further validate our WISKET rat line, regarding its translational utility in schizophrenia research, we examined their social behavior and introduced a short and simple holeboard (HB)-like test to investigate their motivational deficit that predicts the cognitive disturbance...

OBJECTIVE: To assess the validity of the e-OAKHQOL questionnaire and analyze whether the answers were affected by the form of administration (electronic vs. paper). METHODS: Two samples of patients with knee osteoarthritis were constituted. The first was recruited by general practitioners. Patients could choose to respond to the electronic or paper version. The second included subjects who responded to the paper version and were matched with respondents to the electronic version in the first sample...

Aims Bullying is a prevalent issue in society, with adverse effects ranging from psychological symptoms to somatic ailments like chronic pain. The purpose of this study was to generate new knowledge about the underlying mechanisms behind this association. Using an animal model, we investigated the changes in microRNA expression in plasma, in the pituitary gland and the adrenal gland following social stress. Methods A resident-intruder paradigm where male Sprague Dawley rats (intruders) were exposed to male Long Evans rats (resident) 1 h daily for a week was used...

Psychosocial factors such as anxiety, depression and catastrophizing, commonly associated with established chronic pain, also may be associated with an increased risk of chronic postsurgical pain (CPSP) when present preoperatively. We used a repeat social defeat (RSD) paradigm to induce psychosocial stress in rodents prior to incisional surgery of the paw. Mixed effects growth curve models were utilized to examine resolution of mechanical hypersensitivity in rats for four weeks following surgery. Eight days following surgery, immunohistochemistry was conducted to examine glial activation as well as evoked neuronal activation in the spinal cord...

PURPOSE: Lumbar intervertebral disc degeneration is a common cause of lower back pain that affects the physical and mental health of patients and increases social burden. Parathyroid hormone has been reported to be effective at inhibiting disc degeneration; however, these effects have not been fully established in vivo in ovariectomized (OVX) rats. Thus, in this study, we aimed to address this issue and examine the effects of parathyroid hormone treatment in OVX rats. METHODS: Thirty female Sprague-Dawley rats, three months-old, were subjected to sham or ovariectomy surgery...

Despite several advances in percutaneous coronary intervention and the discovery of new drugs, the incidence of myocardial infarction and deaths due to cardiovascular diseases (CVD) has not decreased markedly in China. The quality of life is affected seriously, which further results in great social and family burden. Many drugs, from the century-old aspirin to the newly FDA-approved Byvalson, have been proven to be effective in the treatment and prevention of CVD. As clinically reported, those life-saving drugs still have their side effects in regards to the narrow therapeutic indexes influenced by individual genetic variations...

Empathy, which is a highly cognitive and emotional process, is the ability to share the emotional states of others. Empathy has also been observed in rodents. The empathic sharing of the distressful experience of a conspecific can even motivate altruistic behaviors, which are critical for survival. However, previous studies investigating empathy or prosocial behaviors in rodents mainly employed fearful or other stressful stimuli to elicit emotional changes; whether pain empathy can also motivate prosocial behaviors has yet to be investigated...

Empathy for pain (vicariously felt pain), an ability to feel, recognize, understand and share the painful emotions of others, has been gradually accepted to be a common identity in both humans and rodents, however, the underlying neural and molecular mechanisms are largely unknown. Recently, we have developed a rat model of empathy for pain in which pain can be transferred from a cagemate demonstrator (CD) in pain to a naïve cagemate observer (CO) after 30 min dyadic priming social interaction. The naïve CO rats display both mechanical pain hypersensitivity (hyperalgesia) and enhanced spinal nociception...

The hippocampal area Cornu Ammonis (CA) CA2 is important for social interaction and is innervated by Substance P (SP)-expressing supramammillary (SuM) nucleus neurons. SP exerts neuromodulatory effects on pain processing and central synaptic transmission. Here we provide evidence that SP can induce a slowly developing NMDA receptor- and protein synthesis-dependent potentiation of synaptic transmission that can be induced not only at entorhinal cortical (EC)-CA2 synapses but also at long-term potentiation (LTP)-resistant Schaffer collateral (SC)-CA2 synapses...

Neonatal injury is associated with persistent changes in sensory function and altered nociceptive thresholds that give rise to aberrant pain sensitivity in later life. Although these changes are well documented in adult rodents, little is known about the consequences of neonatal injury during adolescence. Because adolescence is a critical developmental period during which persistent pain conditions can arise, we examined the effect of neonatal injury on nociception, social behavior, and response to morphine in adolescent Sprague Dawley rats...

The medial prefrontal cortex (mPFC) is critical for selecting and shaping complex behavioral responses. In rodent models of neuropathic pain there is evidence for both structural and functional changes in the mPFC. Brain derived neurotrophic factor (BDNF) plays a critical role in the normal functioning of the mPFC. It has been suggested that the disruption of complex behaviors and mood seen in some neuropathic pain patients is mediated in part by alterations of BDNF in this cortical region. In Sprague-Dawley rats, mPFC levels of BDNF and TrkB mRNA and protein, were quantified and compared to controls (n = 24) 6 days after either: (a) halothane (1...

Clinical data have shown that chronic exposure to stress may be accompanied by an enhancement of inflammation-related pain sensitivity. In this context, little is however known on the impact of stress on neuropathic pain. In the present study we addressed this issue by combining the chronic constriction injury (CCI) model with an ongoing social stress (OSS) paradigm. Cold plate and von Frey tests were performed in 48 rats divided into four groups: OSS exposed to OSS, CCI subjected to chronic nerve constriction, OSS+CCI with a combination of neuropathy and stress and CON, a control group lacking any manipulation...