The Influence of Age and Gender on the Serum XOR Activity, Leukocyte Gene Expression of XOR and MPO, and Biochemical Parameters in Newborn Foals.

This research investigates how age and gender influence the activity of certain immunological and biochemical markers in the blood of newborn foals up to 60 days old. The study found that age affects the activity of an enzyme called xanthine oxidoreductase (XOR), as well as the expression of certain genes in white blood cells, and various biochemical parameters.

Understanding the Research

• This study was focused on the early immune response of newborn foals on a cellular level, particularly the use of oxidative enzymes which are some of the first lines of defense against pathogens.
• The exclusive focus of the study was on healthy Darehshuri newborn foals, a particular breed of horse.
• The study took blood samples from 16 foals at different times: 1, 7, 15, 30, and 60 days after birth. These blood samples were tested for various parameters.

Xanthine Oxidoreductase (XOR) Activity

• XOR is an enzyme involved in purine metabolism, the process by which cells break down and recycle proteins. XOR activity was seen to be high at birth, possibly due to physiological hypoxia during birth, a natural process where oxygen levels decrease momentarily.
• Following birth, XOR activity decreased significantly. The researchers believe this could be due to a decrease in the substrates XOR uses for its activity, and a feedback inhibition of XOR by uric acid.
• Interestingly, there were no sex differences observed in XOR activity.

Gene Expression of XOR and Myeloperoxidase (MPO)

• While XOR activity lowered with age, there was no significant change seen in the gene expression of XOR.
• A different gene expressed in white blood cells, myeloperoxidase (MPO), showed increased expression at 30 days. MPO is involved in the immune response, particularly the process where white blood cells engulf and break down pathogens (phagocytosis). The researchers propose that this may be why MPO expression increases, to boost the foal’s immune response.

Biochemical Parameters

• Certain biochemical parameters also changed with age. For example, levels of total protein, albumin, and creatinine were found to be higher at birth and lowered afterward.
• Conversely, uric acid levels were found to be low at birth and then increase. Uric acid is a by-product of purine metabolism, which XOR is involved in, so the researchers suggest there may be a link between these observations.

In conclusion, this study found that various factors such as XOR activity, gene expression within white blood cells, and several biochemical parameters change in newborn foals in the first 60 days of life. These changes were shown to be influenced by age and (in the case of MPO expression) sex, providing new insights into the early development of the immune system in foals.