Changes in expression of Piezo2 in spinal cord neurons in a rat model of bone cancer pain

Abstract

Objective To evaluate the changes in the expression of Piezo2 in spinal cord neurons in a rat model of bone cancer pain. Methods Sixty-four pathogen-free healthy adult female unmated Sprague-Dawley rats, weighing 160-200 g, were divided into 2 groups (n=32 each) using a random number table: sham operation group (group S) and bone cancer pain group (group BP). Bone cancer pain was induced by injecting breast cancer cells into the abdominal cavity.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before inoculating breast cancer cells and 7, 14 and 21 days after inoculation (T0-3). Eight rats were sacrificed after measurement of MWT, and their lumbar enlargement segments of the spinal cord were removed for determination of Piezo2 expression by Western blot and immunofluorescence.The coexpression of Piezo2 with the neuronal marker NeuN, microglial marker Iba-1 and astrocyte marker GFAP was detected at T2 using double immunofluorescent staining. Results Compared with group S, the MWT was significantly decreased at T1-3, and the Piezo2 expression in the lumbar enlargement segment of the spinal cord was up-regulated in group BP (P < 0.05). Piezo2 was mainly expressed in the spinal lamina Ⅰ and Ⅱ and co-expressed with NeuN and rarely co-expressed with GFAP or Iba-1. Conclusion The development and maintenance of bone cancer pain are related to up-regulated expression of Piezo2 in the lumbar enlargement segment of the spinal cord in rats. Key words: Bone neoplasms; Pain; Spinal cord; Neuron; Piezo2