It has also been shown that MMP-2 takes part in penetration of sperm into oocyte and functions as acrosin
. Thus, probably this enzyme is located on the inner acrosomal membrane of sperm (4).
Although its main activity is the inhibition of various serine proteases such as trypsin, chymotrypsin, elastase, granzyme K, cathepsin G, acrosin
, and plasmin [3, 4, 10], many studies provided evidences also on its role in many regulatory mechanisms, such as inhibition of IL-8 gene expression induced by lipopolysaccharide , neutrophil release of elastase , mast cell release of histamine , urolithiasis , stabilization of the lysosomal membrane , stimulation of fibroblast growth , and regulation of smooth muscle contraction by modulating calcium intracellular levels , as well as in supporting the formation of the hyaluronan-containing extracellular matrix  and in inhibiting the formation of kidney stone .
A polymorphism in the TNF-[alpha]_308 gene was associated with a significant decrease of sperm count, sperm motility, normal sperm morphology, and acrosin
activity of human spermatozoa by means of a simple gelatinolytic technique: a method useful for IVF.
Cryopreservation causes permanent functional damage to sperm viability that can be explained partially by the reduction in the percentage of normal intact acrosomes and in total acrosin
In addition to trypsin, SPINK1 inhibits plasmin, urokinase type plasminogen activator, and acrosin
, but the inhibition of the first 2 is much less efficient than that of trypsin.
Agarwal, "Relationship between acrosin
activity of human spermatozoa and oxidative stress," Asian Journal of Andrology, vol.
. In: Human Spermatozoa in Assisted Reproduction.
Several methods have been developed such as cervical mucus penetration, oocyte penetration assay, and measurement of acrosin
activity (World Health Organization, 1992).
In the Ap and N-9 treated groups the number of acrosome reacted cells were found to be high and it also caused agglutination of the sperms indicating the loss of intactness of the plasma membrane which was further supported by the significant reduction in the activity of membrane bound 5' nucleotidase and acrosin
Furthermore change of biochemical factors have been recognized during cryopreservation, including depletion of amino acids and lipoproteins, release of glutamic-oxaloacetic transaminase (GOT), decrease in phosphatase activity, decrease in loosely bound cholesterol protein, inactivation of acrosin
enzyme and hyaluronidase, prostaglandins diminution, increase in sodium, decrease in potassium content, reduction of ATP and ADP synthesis and decrease in acrosomal proteolytic activity .
The contents of the acrosome include proteolytic enzymes such acrosin
. These acrosomal lysins dissolve the zona pellucida creating a small hole through which the sperm can pass.