Determination of sperm creatine kinase and its isozyme in infertile patients

Bi LUO; Jian CHEN; Zhu QI

ABSTRACT

BACKGROUND:

As a biochemical marker of cytoplasm, the increased activity of creatine kinase (CK) in human spermatozoa is correlated with both the residual cytoplasma and the ratio of sperm with abnormal func tion. It is a marker of mature sperm and associated with the potential of in semination.

OBJECTIVE:

To investigate the differences of CK activity in sperm and the relative contents of sperm CK-MM and CK-BB isoenzymes between normal fertile males and infertile males, and evaluate its significance in clinical diagnosis of male infertility.

DESIGN:

Case-control observation.

SETTING:

Laboratory of Biochemistry, Family Planning Research Insti tute of Sichuan Province.

PARTICIPANTS:

Ninety-four male infertile patients between January 1999 and October 2000 were selected from the Department of Family Planning Sciences of Sichuan Province, who had no aspermatism with their wives proved to be fertile. The average age of subjects were 31 years. Eighty subjects with the sperm count ＞ 2×1010 L-1 were taken as normal sperm group and 14 subjects with the sperm counts ＜ 2×1010 L-1 were considered as oligospermia group. Semen obtained from 27 healthy males who were normal in routine examinations and with children was taken as the healthy control group.

METHODS:

Semen sample collected by masturbation after abstinence of 3 to 5 days was incubated at 37 ℃ for liquefication and routinely analyzed.Total activity of CK in sperm was determined by using a kinetic spectrophotometry and the relative contents of CK isozyme was determined by agarose gel electrophoresis followed by density scanning of CK isozyme.MAIN OUTCOME

MEASURES:

Sperm counts, percentages of viability and motility of sperm, total CK activity and the relative contents of CK-MM and CK-BB isozyme in spermatozoa.

RESULTS:

A total of 94 enrolled patients and 27 normal controls were involved in the analysis of results. ①Sperm counts, percentage of viability and motility in oligospermia group ( Ⅱ + Ⅲ, WHO method) were obviously lower than those in the healthy control group, and those in the normal sperm group, except the sperm counts, were remarkably lower than the healthy control group [the sperm counts in healthy control group, normal sperm group and oligospermia group was (6.05 ±0.81 )×1010 L-1, (7.76±1.37)×1010 L-1 and (1.46±0.19)×1010 L-1 respectively (P ＜ 0.01). The survival rate in healthy control group, normal sperm group and oligospermia group was 85.1%,56.8% and 58.2%, P ＜ 0.01, and the sperm motility was 62.9% ,34.6% and 29.5% respectively, P ＜ 0.01].②Total activity of sperm CK in oligospermia group was significantly higher than the healthy control group [respectively (9.000±6.117) and (1.933 ±0.943) kat/108 sperm,P＜ 0.05],although that in the normal sperm group (2.800±0.862) kat/108 sperm was a little higher than the healthy control group, while there were no significant difference between the two groups (P ＞ 0.05).③The relative contents of sperm CK-MM isozyme in the normal sperm group and oligospermia group were obviously decreased (that in the healthy control group, normal sperm group and oligospermia group was 30.5%, 19.0% and 18.0% respectively,P ＜ 0.05), which implied a remarkable difference in sperm differentiation between healthy control group and the latter two groups.

CONCLUSION:

The determination of sperm CK is meaningful for the diagnosis and pathogenesis of oligospermia. More work should be done on the distribution of sperm CK-MM isozyme in different infertile population as well as its importance in the diagnosis of infertility.