Fig. 5

Morn2^–/– sperm show abnormal energy metabolism. A The MMP of spermatozoa collected from the cauda epididymis of adult Morn2^+/– and Morn2^–/– mice was measured using JC-1 as the marker. The morphology of sperm was examined with DIC. The test was replicated three times using distinct biological samples. The red fluorescent signal represents high MMP, while the green fluorescent signal represents low MMP. The scale bar is 30 μm. B The MMP levels of spermatozoa were indicated by the ratio of red to green fluorescence intensity signals of JC-1, with quantitative analysis of fluorescence signal intensity performed using ImageJ. The high/low MMP signal ratio in Morn2^–/– mice (81.93%) was lower than that in Morn2^+/– mice (93.75%). At least 200 spermatozoa were counted in each sample. ** = P < 0.01. The data are shown as the mean ± SEM of three independent experiments using distinct biological samples. Each data point represents the ratio of red to green fluorescence intensity signals of JC-1 in one sample, and Student’s t-tests were performed. C Analysis of ROS levels (green) in spermatozoa collected from the cauda epididymis of Morn2^+/– and Morn2^–/– adult mice. The morphology of sperm was examined with DIC. Fluorescence intensity represents the expression levels of ROS. The test was replicated three times using distinct biological samples. The scale bar is 30 μm. D The quantification of ROS fluorescence values was performed with the use of ImageJ. The ROS levels in Morn2^–/– mice (51.97) were higher than that in Morn2^+/– mice (34.01). At least 200 spermatozoa were counted in each sample. ** = P < 0.01. The data are shown as the mean ± SEM of three independent experiments using distinct biological samples. Each data point represents the ROS fluorescence intensity signals in one sample, and Student’s t-tests were performed. E Analysis of the ATP level in spermatozoa collected from the cauda epididymis of Morn2^+/– (1.673 μM) and Morn2^–/– (0.035 μM) adult mice. ** = P < 0.01. Data are shown as the mean ± SEM of three independent experiments using distinct biological samples. Each data point represents the ATP level of spermatozoa collected from one sample, and Student’s t-tests were performed