Human Umbilical Cord Blood–Derived CD34⁺ Cells Can Be Used as a Prophylactic Agent for Experimental Heatstroke

Abstract

We attempted to assess the prophylactic effect of human umbilical cord blood–derived CD34⁺ cells in experimental heatstroke. Anesthetized rats, 1 day before heat stress, were divided into 2 major groups and given CD34⁻ cells (defined by 1 × 10⁶ human cord blood lymphocytes and monocytes that contained <0.2% CD34⁺ cells) or CD34⁺ cells (defined by 1 × 10⁶ human cord blood lymphocytes and monocytes that contained >95% CD34⁺ cells). They were exposed to ambient temperature of 43°C for 70 min to induce heatstroke. When the CD34⁻ cells–treated or untreated rats underwent heat stress, their survival time values were found to be 20 – 24 min. Pretreatment with CD34⁺ cells significantly increased survival time (123 – 351 min). As compared with normothermic controls, all CD34⁻ cells–treated heatstroke animals displayed hypotension, hepatic and renal failure, hypercoagulable state, activated inflammation, and cerebral ischemia and injury. However, these heatstroke reactions all were significantly suppressed by CD34⁺ cells pretreatment. In addition, the levels of interlukin-10 in plasma and glial cell line–derived neurotrophic factors in brain were all significantly increased after CD34⁺ cell administration during heatstroke. Our data indicate that human umbilical cord–derived CD34⁺ cells can be used as a prophylactic agent for experimental heatstroke.