Mykkänen A K, Pösö A R, McGowan C M, McKane S A
Department of Basic Veterinary Sciences, University of Helsinki, Finland.
Equine Vet J Suppl. 2010 Nov(38):161-6. doi: 10.1111/j.2042-3306.2010.00205.x.
In exercising horses, up to 50% of blood lactate is taken up into red blood cells (RBCs). Lactate transporter proteins MCT1, MCT2 and CD147 (an ancillary protein for MCT1) are expressed in the equine RBC membrane. In Standardbreds (SB), lactate transport activity is bimodally distributed and correlates with the amount of MCT1 and CD147. About 75% of SB studied have high lactate transport activity in RBCs. In other breeds, the distribution of lactate transport activity is unknown.
To study whether similar bimodal distribution of MCT1 and CD147 is present also in the racing Finnhorse (FH) and Thoroughbred (TB) as in the SB and to study the distribution of MCT2 in all 3 breeds and to determine if there is a connection between MCT expression and performance markers in TB racehorses.
Venous blood samples were taken from 118 FHs, 98 TBs and 44 SBs. Red blood cell membranes were purified and MCT1, MCT2 and CD147 measured by western blot. The amount of transporters was compared with TB performance markers.
In TBs, the distribution of MCT1 was bimodal and in all breeds distribution of MCT2 unimodal. The amount of CD147 was clearly bimodal in FH and SB, with 85 and 82% expressing high amounts of CD147. In TBs, 88% had high expression of CD147 and 11% low expression, but one horse showed intermediate expression not apparent in FH or SB. Performance markers did not correlate with the amount of MCT1, MCT2 or CD147.
High lactate transport activity was present in all 3 racing breeds, with the greatest proportion in the TB, followed by the racing FH, then SB. There was no significant statistical correlation found between lactate transporters in RBC membrane and markers of racing performance in the TB.
在运动的马匹中，高达50%的血乳酸被摄取到红细胞（RBC）中。乳酸转运蛋白MCT1、MCT2和CD147（MCT1的辅助蛋白）在马的红细胞膜中表达。在标准赛马（SB）中，乳酸转运活性呈双峰分布，且与MCT1和CD147的量相关。约75%被研究的标准赛马红细胞具有高乳酸转运活性。在其他品种中，乳酸转运活性的分布情况未知。
研究芬兰赛马（FH）和纯种马（TB）是否也存在与标准赛马中类似的MCT1和CD147双峰分布，研究MCT2在所有这三个品种中的分布，并确定纯种赛马中MCT表达与性能指标之间是否存在关联。
采集了118匹芬兰赛马、98匹纯种马和44匹标准赛马的静脉血样本。纯化红细胞膜，通过蛋白质免疫印迹法测定MCT1、MCT2和CD147。将转运蛋白的量与纯种赛马的性能指标进行比较。
在纯种马中，MCT1的分布呈双峰，而在所有品种中MCT2的分布呈单峰。芬兰赛马和标准赛马中CD147的量明显呈双峰，分别有85%和82%表达大量的CD147。在纯种马中，88%高表达CD147，11%低表达，但有一匹马表现出中等表达，这在芬兰赛马或标准赛马中不明显。性能指标与MCT1、MCT2或CD147的量不相关。
所有这三个赛马品种均存在高乳酸转运活性，其中纯种马中比例最高，其次是芬兰赛马，然后是标准赛马。在纯种马中，红细胞膜中的乳酸转运蛋白与赛马性能指标之间未发现显著的统计学相关性。
