Melatonin rescues impaired penetration ability of human spermatozoa induced by mitochondrial dysfunction.

Fertilization failure often occurs during in vitro fertilization (IVF) cycles despite apparently normal sperm and oocytes. Accumulating evidence suggests that mitochondria play crucial roles in the regulation of sperm function and male fertility. 3-Nitrophthalic acid (3-NPA) can induce oxidative stress in mitochondria, and melatonin, as an antioxidant, can improve mitochondrial function by reducing mitochondrial oxidative stress. The role of sperm mitochondrial dysfunction in fertilization failure during IVF is unclear. The present study revealed that spermatozoa with low, or poor, fertilization rates had swollen mitochondria, increased mitochondria-derived ROS, and attenuated mitochondrial respiratory capacity. 3-NPA treatment enhanced mitochondrial dysfunction in sperm. Spermatozoa with poor fertilization rates, and spermatozoa treated with 3-NPA, had reduced penetration ability. The concentration of melatonin was decreased in semen samples with low and poor fertilization rates. Melatonin, not only decreased excessive mitochondria-derived ROS, but also 'rescued' the reduced penetration capacity of spermatozoa treated with 3-NPA. Taken together, the study suggested that mitochondria-derived ROS and mitochondrial respiratory capacity are independent bio-markers for sperm dysfunction, and melatonin may be useful in improving sperm quality and overall male fertility.

[Short-term medication of L-carnitine before intracytoplasmic sperm injection for infertile men with oligoasthenozoospermia].

OBJECTIVE: To observe the pregnancy promoting effect of L-carnitine combined with intracytoplasmic sperm injection (ICSI) in treating male infertility with oligoasthenozoospermia. METHODS: We assigned 129 patients with oligoasthenozoospermia to receive 2 weeks of oral L-carnitine followed by ICSI (medication group, n = 42) and ICSI alone (control group, n = 87). We compared the sperm concentration and motility, the percentage of grade a + b sperm, and sperm deformity before and after L-carnitine medication, as well as the rates of fertilization, cleavage, available embryo and clinical pregnancy between the two groups. RESULTS: The percentage of grade a + b sperm was significantly increased after L-carnitine medication as compared with the baseline ([13.5 +/- 10.7] % vs [9.6 +/- 7.2] %, P<0.05), and so was the rate of available embryo in the medication group after ICSI in comparison with that of the control group (77.50% vs 69.04%, P<0.05). CONCLUSION: Short-term medication of L-carnitine can improve sperm quality and raise the success rate of ICSI.

[Causes of urinary tract infection and its prevention in patients with indwelling urinary catheter: report of 152 cases].

OBJECTIVE: To investigate the causes of urinary tract infections occurring in patients with indwelling urinary catheter, and to find the preventive means against this condition. METHODS: The clinical data of 152 such cases admitted between March, 2000 and February, 2002 in our department were reviewed. RESULTS: In this group of patients, 57 (37.5%) developed urinary infections due to the indwelling catheter, a rate significantly lower than that among previous cases (46.6%, P < 0.05) treated in our department. CONCLUSION: Careful evaluation of the indications for indwelling urinary catheter, strict aseptic procedures and shortened indwelling time of the catheter may help prevent the occurrence of the infection.