Research Article Potential Nociceptive Regulatory Effect of Probiotic Lactobacillus rhamnosus PB01 (DSM 14870) on Mechanical Sensitivity in Diet-Induced Obesity Model Fereshteh Dardmeh, 1,2 Hans Ingolf Nielsen, 1 Hiva Alipour, 1 Benedict Kjærgaard, 3 Erik Brandsborg, 4 and Parisa Gazerani 1,2 1 Biomedicine Group, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark 2 SMI5, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark 3 Department of Clinical Medicine, Te Faculty of Medicine, Aalborg University Hospital, Aalborg, Denmark 4 Bifodan A/S, Hundested, Denmark Correspondence should be addressed to Fereshteh Dardmeh; feda@hst.aau.dk and Parisa Gazerani; gazerani@hst.aau.dk Received 3 March 2016; Accepted 3 August 2016 Academic Editor: Anna Maria Aloisi Copyright © 2016 Fereshteh Dardmeh et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Treatments for obesity have been shown to reduce pain secondary to weight loss. Intestinal microbiota, as an endogenous factor, infuences obesity and pain sensitivity but the efect of oral probiotic supplementation on musculoskeletal pain perception has not been studied systematically. Te present study examined the efect of a single daily oral dose (1 × 10 9 CFU) of probiotics (Lactobacillus rhamnosus PB01, DSM14870) supplement on mechanical pain thresholds in behaving diet-induced obese (DIO) mice and their normal weight (NW) controls. Te mice ( = 24, 6-week-old male) were randomly divided into four groups on either standard or high fat diet with and without probiotic supplementation. Both DIO and NW groups with probiotic supplementation maintained an insignifcant weight gain while the control groups gained signifcant weight ( < 0.05). Similarly, both DIO and NW probiotics supplemented groups demonstrated a signifcantly ( < 0.05) lower sensitivity to mechanical stimulation compared to their corresponding control. Te results of this study suggest a protective efect of probiotics on nociception circuits, which propose a direct result of the weight reduction or an indirect result of anti-infammatory properties of the probiotics. Deciphering the exact underlying mechanism of the weight loss and lowering nociception efect of the probiotic applied in this study require further investigation. 1. Introduction Physiological pain plays a life-essential protective role, while acute or chronic pathological pain indicates a medical prob- lem that needs treatment and imposes a medical challenge [1]. Pain perception is a complex process including neu- ronal, nonneuronal, and cognitive processes modulated by peripheral and central factors. Neurotransmitters, immune cells, and hormones have been demonstrated to contribute in pathogenesis of chronic pain [2]. Several biological and psychological factors may interfere with perception of pain. To mention a few, gender, depression, or genetic factors have been shown to alter pain perception both in humans and animals [3–5]. Since pain is a subjective concept and pain measurement is challenging, it is usually measured under controlled con- ditions, by responses to experimental stimuli as applied by mechanical, thermal, electrical, and chemical stimuli [6]. Pressure pain threshold (PPT) has been identifed as a reliable and easy biomarker in multiple clinical pain states [7, 8]. Rodent withdrawal refex to pressure application upon sensation of pain is interpreted as similar to PPT assessments in humans. Pain threshold is infuenced by several factors, including obesity, which alters adipose tissue metabolic and endocrine Hindawi Publishing Corporation Pain Research and Management Volume 2016, Article ID 5080438, 7 pages http://dx.doi.org/10.1155/2016/5080438