Premium
Diet Induced Obesity Alters Muscle Spindle Afferent Function in Adult Male Mice
Author(s) -
Shamai Krystle,
Nguyen Peter,
Zaytseva Dasha,
Wilkinson Katherine
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.818.10
Subject(s) - muscle spindle , medicine , proprioception , endocrinology , afferent , sciatic nerve , anatomy , chemistry , physical therapy
Balance impairment and chronic low level systemic inflammation have both been associated with obesity. As inflammatory factors have been shown to alter the activity of Group Ia/II muscle spindle afferents (Delliaux et al., 2009), we hypothesized that obesity would lead to a reduced response to stretch and less sensitivity to vibrations in muscle spindle afferents. Five‐week‐old male C57Bl/6 mice were fed either a high fat diet (HFD; 60% kcal from fat, Research Diets) or a control diet (10% kcal from fat) for 10 weeks. Mice fed a HFD were significantly heavier after 10 weeks than controls (HFD = 37.6g ± 3.52[SD]; control = 28.1g ± 2.60[SD]; p < 0.05). The extensor digitorum longus muscle and innervating sciatic nerve were dissected and placed into an in vitro bath. Muscle spindle afferent activity was recorded during ramp and hold stretches of three physiological stretch lengths and during 10‐100Hz frequency vibrations. Muscle spindle afferent firing frequencies increased linearly in both HFD (n = 14) and control (n = 13) groups in response to increasing stretch lengths, which is characteristic of muscle spindle afferents. Obese mice exhibited a decreased response to stretch (p < 0.05), though, suggesting that improper proprioceptive information from the periphery is reaching the central nervous system. Fewer obese muscle spindle afferents entrained to 50 or 100Hz vibrations than control afferents, indicating that there is also less sensitivity of muscle spindle afferents to dynamic length changes in obese mice. Decreased sensitivity of muscle spindle afferents may at least partially explain the balance impairment seen in obesity. This work was supported by a CSUPERB New Investigator Grant (KAW) and a Department of Biological Sciences Research Fellowship (KS).