Measurement of erythrocyte carbonic anhydrase isozymes (CA-I and CA-II) in racehorses and riding horses.

The research article discusses the procedures and results from an investigation into the concentrations of carbonic anhydrase isozymes (CA-I and CA-II) in the red blood cells of racehorses and riding horses. Notably, the study suggests that levels of these enzymes may be affected by chronic physical stress in racehorses.

Research Objectives and Methodology

• The main goal of this research was to measure the levels of two carbonic anhydrase enzymes (CA-I and CA-II) in equine erythrocytes (red blood cells), specifically in racehorses and riding horses.
• The enzymes were purified from the red blood cells through column chromatography, a common purification technique in biochemistry.
• Anti-CA-I and anti-CA-II sera were produced in rabbits. These are antibodies against the CA-I and CA-II enzymes which can bind to the enzymes and help in their detection.
• The researchers developed sensitive enzyme-linked immunosorbent assays (ELISAs), which are often used for detecting substances such as peptides, proteins, antibodies, and hormones in biological samples.
• The study included analysis of erythrocytes from 150 clinically normal thoroughbreds, comprising 123 racehorses and 27 riding horses.

Key Findings

• Using the ELISA, researchers determined the concentrations of CA-I and CA-II in both types of horses. Concentrations are referred to in milligrams per gram of hemoglobin, a protein in red blood cells.
• Results indicated a difference in enzyme levels between racehorses and riding horses. Specifically, racehorses had higher levels of CA-II but lower levels of CA-I compared to riding horses.
• CA-I concentrations in racehorses were found to be 1.70 +/- 0.48 mg/g Hb, while riding horses had a concentration of 2.34 +/- 0.52 mg/g Hb. CA-II concentrations were 0.94 +/- 0.13 mg/g Hb and 0.76 +/- 0.08 mg/g Hb in racehorses and riding horses, respectively.
• These differences in enzyme levels suggest that chronic physical stress, often associated with the racing lifestyle, may impact the erythrocytes of racehorses.
• The research also followed the development of CA-I levels in young horses, finding an increase during the first year of life and normal adult levels being reached by two years of age. On the contrary, CA-II levels slightly diminished with age suggesting different regulatory processes for these two enzymes during development.