**2. Proposed side effects for sperm cryopreservation**

Sperm cryopreservation is unavoidably linked to a reduction in sperm quality, which has been related to cold shock and freezing damages. The importance of cold shock injuries var‐ ies with the species, the composition of the extender, the cryoprotectant selected and the male, among other factors [10,11]. Seldom more than 50% of the sperm population survives cryopreservation [9].

Deleterious effects of freezing/thawing procedures originate a reduction on the sperm life span due to alterations in the structure and functions of spermatozoa. Side effects in‐ clude altered motility, changes in the plasma membrane and acrosomal integrity and in‐ creased DNA fragmentation. All these alterations induce a reduction of the sperm ability to survive in the female reproductive tract and to interact with the oocyte at fertilization [8,12]. In an attempt to compensate these side effects, seminal doses are usually pre‐ pared with excessive numbers of spermatozoa in order to improve AI fertility [5,8].

Available cryopreservation techniques have a number of potentially detrimental problems, such as physical and chemical injuries that prone the spermatozoa to cell death and dysfunc‐ tion (Figure 2). These include [9,13-15]:

**Figure 2.** Proposed deleterious effects in sperm cryopreservation [Ca2+ - calcium].

**3.1. Assessment of events associated with sperm capacitation**

nalling pathways are disturbed [17].

The most frequently used methods of sperm analysis have been pleasantly reviewed in a re‐ cent InTech publication [11], driving the main topic of this review into new adjunctive meth‐ ods available to test sperm quality (Figure 3). These tests can be performed as well in freshly ejaculated sperm or in preserved samples. In the former, it would allow to increase the abili‐ ty to predict sperm quality, the selection of donor/sperm for cryopreservation and to assess infertility causes. In the later it could be of utmost interest to study the sperm response to preservation trials, such as the design of a new extender. Further, it could also be of impor‐ tance when studying the sperm response to preservation in new species, where it would al‐ low the identification of the most suitable molecular and functionally-friendly extender or

Molecular Markers in Sperm Analysis http://dx.doi.org/10.5772/52231 97

For long, it has been accepted that freezing/thawing procedures induce a capacitation-like status that originate losses on the fertilizing potential of spermatozoa. Non-capacitated live sperm cells survive longer in the female genital tract than capacitated sperm [16]. Dysfunc‐ tion of intracellular pathways associated with calcium (Ca2+) predisposes to acrosome insta‐ bility and exocytosis of its content. Regulation of protein function by Ca2+ signalling pathways is central for most sperm functions and infertility is often found when those sig‐

**3. Biological markers of sperm function**

procedure.


**Figure 2.** Proposed deleterious effects in sperm cryopreservation [Ca2+ - calcium].
