Veterinary Research Forum

Abstract Crocetin (CRT) is one of the active chemical compounds of saffron and has many biological effects such as antioxidant property. The present study investigated the effects of CRT on crushed sciatic nerve function. Vitamin (Vit) C was used as an antioxidant drug. Thirty rats were divided into six groups including intact, sham, crush, CRT 7.50, CRT 30.00 and Vit C 100. Nine other rats with no surgery were scheduled in three groups to receive 7.50 and 30.00 mg kg^-1 CRT and 100 mg kg^-1 Vit C. In anesthetized rats, right sciatic nerve was crushed using a small hemostatic forceps. Sciatic functional index values on days five, 10, 15 and 20 after crush were accelerated, the severities of sciatic nerve degeneration and gastrocnemius muscle atrophy were ameliorated, and the increased malondialdehyde level and the decreased superoxide dismutase activity in the serum were restored by 20 consecutive days of oral administration of 30.00 mg kg^-1 CRT and 100 mg kg^-1 Vit C. No significant differences were observed between 30.00 mg kg^-1 and 100 mg kg^-1 Vit C. The groups that did not have surgery but received CRT (7.50 and 30.00 mg kg-1) and Vit C (100 mg kg-1) showed no behavioral, histopathological and biochemical alterations when compared to intact group. It was concluded that CRT and Vit C produced similar improving effects on crushed-injured sciatic nerve function. Inhibition of oxidative stress, enhancement of endogenous antioxidant activity might be involved in improving effects of CRT and Vit C.

Abstract Doxorubicin (DOX), as a potent anti-cancer agent, exerts side effects in vital organs. Various chemical compounds with tissue protective properties are used to prevent the side effects of DOX. This study was planned to investigate the effects of histidine (HIS) and N-acetylcysteine (NAC) ​​on DOX-induced acute kidney injury. The possible mechanisms were followed by determining the histopathological changes of the kidney along with the biochemical alterations of the blood and kidney tissue. Forty-eight rats were divided into eight groups of six animals each to receive normal saline and DOX after alone and combined treatments with HIS and NAC. The DOX at a single dose of 15.00 mg kg^-1 was intraperitoneally injected on day one. The separate and combined intraperitoneally injections of HIS and NAC at a similar dose of 100 mg kg^-1 were began 30 min after DOX administration and continued for seven consecutive days. The DOX increased kidney weight and caused congestion, hemorrhages and degeneration in kidney tissue. It also increased serum urea and creatinine concentrations and kidney tissue levels of malondialdehyde, tumor necrosis factor-alpha and caspase-3, and decreased superoxide dismutase activity in this tissue. Separate and combined treatments with HIS and NAC improved all the above-mentioned effects of DOX. The restoring effects of the combined treatment were more prominent than the effect of amino acids alone. It was concluded that anti-oxidative, anti-inflammatory and anti-apoptotic mechanisms might be related to the tissue protective effects of HIS and NAC against DOX-induced acute renal injury.

Abstract Surgery commonly causes post-operative pain that should be alleviated to prevent complications. In addition to the use of synthetic drugs, there has been a widespread desire to use medicinal plants for surgical pain management. Thymoquinone (TQ), a constituent of Nigella sativa black seeds, exhibits a potent anti-oxidant property. Celecoxib (CLX), a potent non-steroidal anti-inflammatory drug, is widely used in pain management. In the present study, the effects of TQ and CLX on pain caused by hind paw surgical incision were compared. Fifty-six rats were divided into four groups of 14 rats as intact, vehicle, TQ, and CLX groups. In each group, six rats were planned to record pain-related behaviors on days 1 - 10 and eight rats were designed for determination of serum biochemical alterations on days 1 (four rats) and 3 (four rats) after surgery. Oral administrations of TQ and CLX at a same dose of 10.00 mg kg^-1 alleviated paw lifting number (spontaneous pain) and paw withdrawal threshold evoked by von Frey filaments on metal mesh floor, improved the decreased contents of serum total anti-oxidant capacity and superoxide dismutase, and restored the increased levels of serum malondialdehyde and tumor necrosis factor-alpha. The results suggested that TQ by employing anti-oxidant and anti-inflammatory mechanisms, might relieve the pain induced by hind paw plantar incision, being comparable with CLX.

Abstract Neuroprotective effects for natural products are supported by several studies. In this regard, safranal, a constitute of saffron, has the potential to exert beneficial effects in neurological disorders such as Parkinson's disease, epilepsy, stroke, multiple sclerosis and Alzheimer's disease. Here, we investigated the effect of safranal on penicillin-induced epileptiform activity. Also, the effects of intracerebroventricular (ICV) microinjection of AM251 as a CB1-cannabinoid receptors antagonist to clarify the possible mechanism of safranal were evaluated. Epileptiform activity was induced by intra-cortical administration of penicillin (300 IU, 1.50 μL) in urethane-anesthetized rats. Electrocorticographic recordings were used to analyze the frequency and amplitude of spike waves. Intraperitoneal injections of safranal at doses of 1.00 and 4.00 mg kg^-1 significantly reduced both the number and amplitude of spike waves. The ICV microinjection of AM251 (0.50 μg 2.00 μL^-1) significantly increased the frequency and amplitude of spike waves. In addition, the anti-epileptic effect induced by administration of safranal at a dose of 4.00 mg kg^-1 was partially prevented by ICV microinjection of 0.50 μg 2.00 μL^-1 of AM251. The results showed anti-epileptiform activities for safranal. Central CB1 cannabinergic receptors might be involved in the anti-epileptiform activity of safranal.

Abstract Crocin is a plant-derived carotenoid and bears potent antioxidant property. Ranitidine (a histamine H₂ receptor blocker) is used for peptic ulcer treatment. The present study was planned to investigate the effects of crocin and ranitidine on indomethacin-induced ulcer in small intestine of rats. Animals were randomized into two major groups including indo-methacin (10.00 mg kg^-1, ulcer group, 48 rats) and normal saline (1.00 mL kg^-1, intact group, 48 rats) groups. Each of these two major groups was subdivided into eight subgroups for intra-peritoneal (IP) injections of normal saline, crocin (2.50, 10.00 and 40.00 mg kg^-1), ranitidine (5.00 and 20.00 mg kg^-1), crocin (2.50 and 10.00 mg kg^-1) plus ranitidine (5.00 mg kg^-1). Indomethacin induced intestinal ulcer was characterized by bleeding, inflammation, epithelial hyperplasia and crypt loss. This non-steroidal anti-inflammatory drug (NSAID), indomethacin decreased goblet cell number and superoxide dismutase (SOD) activity and increased small intestine weight, organo-somatic index (OSI), malodealdehyde (MDA), tumor necrosis factor-α (TNF-α) and caspase-3 contents of intestine. Crocin resolved all the above-mentioned parameter changes induced by indomethacin. These treatments produced no significant effects on the above-mentioned parameters of intact group. The results of the present study showed tissue protective and anti-ulcer effects of crocin on small intestine by antioxidant, anti-inflammatory and anti-apoptotic mechanisms. Ranitidine alone showed no effect; however, in combination with crocin it exerted recovery effects. It is recommended that crocin, be considered as a therapeutic agent for NSAIDs-induced intestinal damage management.

Abstract Vitamin B₁₂ modulates pain at the local and peripheral levels. This study has investigated the effects of intracerebroventricular (ICV) injection of vitamin B₁₂ on themuscle pain. We used diclofenac (cyclooxygenase inhibitor) and naloxone (opioid receptors antagonist) to clarify the possible mechanisms. For ICV injections, a guide cannula was implanted in the left lateral ventricle of the brain. Muscle pain was induced by intramuscular injection of formalin (2.50%; 50 µl) in the right gastrocnemius muscle and the number of paw flinching was recorded at 5-min blocks for 60 min. Locomotor activity was performed using an open-field test. Formalin induced a biphasic pain. Vitamin B₁₂ (1.25, 2.50, 5.00 and 10.00 µg per rat) and diclofenac (12.50 and 25.00 µg per rat) significantly reduced both phases pain intensity. Significant antinociceptive effects were observed after combined treatments of diclofenac (6.25 and 12.50 µg per rat) with vitamin B₁₂ (0.63 and 2.50 µg per rat), respectively. Prior ICV injection of naloxone (10.00 µg per rat) prevented vitamin B₁₂ (10.00 µg per rat) and diclofenac (25.00 µg per rat) induced antinociceptive effects. All the above-mentioned chemicals did not alter locomotor behavior in an open-field test. The present results showed that the cyclooxygenase pathway and opioid receptors may be involved in the central antinociceptive effect of vitamin B₁₂. In addition, opioid receptors might be involved in diclofenac-induced antinociception.

Abstract The parafascicular nucleus (PFN) of thalamus, as a supraspinal structure, has an important role in processing of nociceptive information. In addition, μ-opioid receptor contributes to supraspinal modulation of nociception. In the present study, the effects of microinjection of naloxone (a non-specific opioid-receptor antagonist) and naloxonazine (a specific μ-opioid receptor antagonist) were investigated on morphine-induced antinociception in a rat model of acute trigeminal pain. Right and left sides of PFN of thalamus were implanted with two guide cannulas. Acute trigeminal pain was induced by local corneal surface application of hypertonic saline and the number of eye wipes as a pain index was recorded for 30 sec. Microinjection of morphine at doses of 1, 2 and 4 μg per site significantly (p < 0.05) decreased the number of eye wipes. Alone microinjection of naloxone (4 μg per site) and naloxonazine (1 and 2 μg per site) significantly (p < 0.05) increased corneal pain severity. Prior microinjection of naloxone (2 and 4 μg per site) and naloxonazine (1 and 2 μg per site) significantly (p < 0.05) prevented the antinociceptive effect induced by morphine (4 μg per site). All the above-mentioned chemicals did not alter locomotor behavior in an open-field test. The results of the present study showed an antinociceptive effect of morphine at the PFN level of thalamus. Mu-opioid receptor of the PFN of thalamus may be involved in morphine-induced antinociception.

Abstract The present study was performed to investigate the effects of long-term intraperitoneal (IP) injection of vitamin B₁₂ and diclofenac in separate and combined treatments on cold and mechanical allodynia in a neuropathic pain model in rats. Neuropathic pain was induced by crush injury in right tibial nerve. Acetone spray and von Frey tests were used to obtain cold and mechanical allodynia responses, respectively, on day 11 after nerve crush. Normal saline, vitamin B₁₂ and diclofenac were injected intraperitoneally for 10 consecutive days after surgery. Normal saline treated rats showed cold and mechanical allodynia responses after nerve crush. Vitamin B₁₂ at doses of 50, 100 and 200 µg kg^-1 and diclofenac at a dose of 2 mg kg^-1 produced antiallodynic effects. Antiallodynic effects were not observed when subanalgesic doses of vitamin B₁₂ (25 µg kg^-1) and diclofenac (0.25 mg kg^-1) were used together. By increasing the dose of vitamin B₁₂ to an effective dose (100 µg kg^-1), antiallodynic effects were observed when compared with diclofenac (0.25 mg kg^-1) alone. The results indicated that vitamin B₁₂ and diclofenac produced neuropathic pain suppressing effects. Moreover, a potentiation effect was observed between vitamin B₁₂ and diclofenac.