Time-dependent photobiomodulation management of neuropathic pain induced by spinal cord injury in male rats.

Neuropathic pain (NP) following spinal cord injury (SCI) often lasts for a long time and causes a range of problems that reduce the quality of life. Current treatments are not generally effective; however, photobiomodulation therapy (PBMT) has made some progress in this area. Due to the novelty of this treatment, standard therapeutic protocols have not yet been agreed upon. In the present study, we compare the analgesic effect of two PBMT protocols (2 and 4 weeks of radiation). A total of thirty-two adult male Wistar rats were divided into four groups: control, SCI, 2 W PBMT, and 4 W PBMT. SCI was induced by an aneurism clip and PBMT used a 660-nm, initiated 30 min post-SCI, and continued daily for 2 or 4 weeks. Functional recovery, hyperalgesia, and allodynia were measured weekly. At the end of the study, the Gad65, interleukin 1-alpha (IL1α), interleukin 10 (IL10), IL4, and purinergic receptor (P2xR and P2yR) expressions were measured. Data were analyzed by Prism6. The results showed PBM irradiation for 2 and 4 weeks had the same effects in improving hyperalgesia. In the case of allodynia and functional recovery, 4 W PBMT was more effective (p<0.01). 4 W PBMT increased the Gad65 expression (p <0.001) and reduced P2Y4R (p <0.05) compared to SCI animals. The effects of 2 and 4 W PBMT were the same for IL1α, IL10, and P2X3 receptors. 4 W PBMT was more effective in reducing the complications of SCI such as pain and disability. PBMT therapy is an effective method aimed at immune system function modulation to reduce NP and motor dysfunction.

Altered plasma visfatin levels and insulin resistance in patients with Alzheimer's disease.

Central insulin resistance is involved in the pathophysiology of Alzheimer's disease (AD). Visfatin (VIS), an adipokine secreted from peripheral adipose tissue, is involved in energy balance and weight control. Besides its metabolic roles, VIS possesses insulin-mimetic, anti-apoptotic, and neuroprotective properties. In this study, we assessed the presence of a correlation between plasma VIS level and insulin resistance or AD. Sixty participants were enrolled in this study; 34 patients with AD and 26 healthy subjects. All subjects underwent comprehensive evaluations including Mini-mental score exam (MMSE) for the diagnosis of dementia. Subjects with MMSE score < 24 were added to the AD group, while healthy subjects should have a MMSE score > 27. Fasting blood sugar (FBS) and insulin levels were measured by enzyme-linked immunosorbent assay. The results indicate a significant elevation in FBS from 103 ± 3.0 to 147 ± 7.6 in AD patients (p ≤ 0.001). Additionally, 71% of AD patients developed insulin resistance, as the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) index increased from 2.9 ± 0.5 in healthy subjects to 5.2 ± 0.7 in AD patients (p ≤ 0.05). Body mass index and serum insulin level did not show a significant alteration, but serum VIS levels were significantly (p ≤ 0.01) lower in AD patients (11.15 ± 1.9 ng/ml) in comparison to control group (21.09 ± 2.3 ng/ml). There is a negative correlation between plasma VIS level and the HOMA-IR index (p < 0.05). The results of this study present clear evidence for systemic insulin resistance and decreased serum VIS level in non-obese, non-overweight patients with moderate to severe AD.

The role of low level laser therapy on neuropathic pain relief and interleukin-6 expression following spinal cord injury: An experimental study.

INTRODUCTION: The effect of Low Level Laser Therapy (LLLT) as a non-invasive treatment of spinal cord injury (SCI) is still under investigation. Therefore, the present study aimed to evaluate the effectiveness of LLLT on neuropathic pain and interleukin-6 (IL-6) expression following SCI in male rats. METHODS: 46 adult male rats were divided into 5 groups of control, SCI, treatment with methylprednisolone sodium succinate (MPSS), 1-week LLLT and 2-week LLLT. Animals underwent behavioral evaluations for motor behavior, level of allodynia and hyperalgesia every week. At the end, spinal cord was extracted and IL-6 level was assessed by ELISA method. RESULTS: Treatment with MPSS and 2-week LLLT had led to motor function recovery (df: 24, 145; F=223.5; p <0.001). SCI did not affect mechanical (df: 24, 145; F=0.5; p=0.09), and cold allodynia (df: 24, 145; F=0.3; p=0.17) but significantly increased mechanical (df: 24, 145; F=21.4; p<0.001) and heat hyperalgesia (df: 24, 145; F=16.1; p<0.001). Treatment with MPSS and 1 and 2-weeks LLLT improved mechanical hyperalgesia (p<0.05) and heat hyperalgesia (p<0.01). The increased level of IL-6 following SCI was also compensated by administration of MPSS or LLLT (df: 4, 10; F=8.74; p=0.003). CONCLUSION: Findings show that long periods of LLLT have better effects in improving the complication of SCI. In summation, since LLLT does not cause the side effects of MPSS, long-term use of LLLT may be a proper alternative for MPSS in decreasing post SCI side effects.