Application of a novel rectal cooling device in hypothermia therapy after cerebral hypoxia-ischemia in rats.

Peng Liu,Zelan Zuo,Rui Yang

doi:10.1186/s12871-016-0239-5

Abstract

BackgroundA new rectal cooling device for therapeutic hypothermia (TH) therapy is designed and is applied in TH treatment of SD rats with ischemic-hypoxic brain damage.MethodsHealthy adult SD rats (n = 45) were randomly assigned into four groups: the healthy control group (n = 5), the ischemia and hypoxia group (n = 10), the rectal TH cooling group (n = 18), and the ice blanket TH cooling group (n = 11). The rats in the rectal cooling and ice blanket TH groups received 12 h treatment after hypoxic-ischemic brain damage had been established, while those in the ischemia and hypoxia group did not. Taking the start of TH as the zero point, rats were sacrificed after 24 h and the brain and rectum tissues were sampled for histological analysis.ResultsThe TH induction time (37.3 ± 14.7 min) in the rectal cooling group was significantly shorter (F = 4.937, P < 0.05) than that in the ice blanket cooling group (75.6 ± 27.2 min). The HE and NISSL staining results showed that rats in the rectal TH cooling group had significantly decreased (P < 0.01) positive neurons cell count compared to those in ischemia and hypoxia group. In addition, TUNEL staining indicated that the number of apoptotic cells (3.9 ± 1.8 cells / × 400 field) and the apoptosis index (4.4 % ± 1.5) were significantly lower in rectal TH cooling group (P < 0.05) than in ischemia and hypoxia group (23.2 ± 12.1 cells / × 400 field, 26.6 % ± 12.1). Also, no rectal frostbite or inflammatory infiltration was observed in rats in the rectal TH treatment groups.ConclusionOur new cooling device realized rapid TH induction in SD rats with ischemic-hypoxic brain damage, inhibited the apoptosis of cells in the hippocampal CAl region, and did not cause histological damage to the rectal tissues.Electronic supplementary materialThe online version of this article (doi:10.1186/s12871-016-0239-5) contains supplementary material, which is available to authorized users.

Highlights

A new rectal cooling device for therapeutic hypothermia (TH) therapy is designed and is applied in TH treatment of SD rats with ischemic-hypoxic brain damage
The rats in the rectal cooling and ice blanket TH groups were treated with therapeutic hypothermia later, but those in the ischemia and hypoxia group received no treatment
During TH maintenance, the tympanic temperature of rats in both groups was maintained within 33–35 °C

Summary

Introduction

A new rectal cooling device for therapeutic hypothermia (TH) therapy is designed and is applied in TH treatment of SD rats with ischemic-hypoxic brain damage. The temperature controlled within 32–34 °C is often considered safe and, Liu et al BMC Anesthesiology (2016) 16:77 is most commonly used for the TH therapy on experiment animals This is because, within this range, the blood pressure, blood oxygen, carbon dioxide partial pressure, blood pH and blood glucose would not be influenced, and no pathological damages would occur in animals’ heart, lung, kidney, small intestine and other organs. Some TH therapy devices introduced by top hospitals are too expensive for hospitals in small counties or villages to afford, and too large to move, limiting their application in prehospital TH treatment. These shortcomings significantly inhibit the promotion of TH therapy, and may even delay the treatment opportunity for critically sick patients

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