[Expression of the CREM gene in the semen and testis of miR-199b-5p knockout male mice].

OBJECTIVE

To investigate the effect of miR-199b-5p knockout on the expression of the CREM gene in the semen and testis of mice.

METHODS

We selected 8 miR-199b-5p knockout (KO) male mice (the KO group) and another 8 wild-type (WT) C57BL/6 male mice (the WT group), and observed the changes in their body weight, testicular index, testis structure and sperm morphology. We detected sperm concentration under the microscope, determined the mRNA and protein expression levels of CREM in the semen and testis by RT-qPCR and Western blot respectively, and predicted the targeting relationship between CREM and miR-199b-5p using the online database.

RESULTS

There were no significant changes in the body weight and testicular index in either of the two groups. Compared with the WT mice, the animals in the KO group showed a slight reduction in both the count and concentration of sperm (P>0.05). Testis pathology exhibited a lower testis volume in the KO than in the WT mice, but no obvious abnormalities in the testis tissue, spermatogenic and supporting cells in the seminiferous tubules, boundary membrane or diameter of the seminiferous tubule. Online database prediction indicated that CREM was the target gene of miR-199b-5p. Both the mRNA and protein expressions of CREM in the semen and testis of the mice were significantly decreased in the KO group compared with those in the WT group (both P<0.05). A six-month follow-up showed a remarkably lower rate of male births in the KO than in the WT mice (P<0.05).

CONCLUSION

The expression of the CREM gene is down-regulated in the semen and testis of miR-199b-5p knockout male mice, and miR-199b-5p may affect the fertility of male mice by targeting CREM.