Coenzyme I

To study the protective effect of NADH on the hematopoietic system of mice against radiation.

Sixty mice were randomized into 3 groups (20/group), Group I serving as normal control group. Three days before exposure to single-dose (6.0 Gy) whole body 60Co gamma-ray irradiation in the other 2 groups, the mice in Group II received injections with 0.9% NaCl and those in Group III with intraperitoneal NADH (10 mg/kg, twice daily). The peripheral white blood cells count was carried out in the blood samples from the mouse tail vein at different time after the exposure, and the bone marrow smears were prepared with routine staining to examine the number of the granulocytes and determine their mitotic index 24 h after radiation. DNA fragmentation in mouse bone marrow cells was detected by DNA electrophoresis 24 and 48 h after irradiation.

The white blood cell count was significantly higher in mice with coenzyme I treatment before exposure to the irradiation. NADH also increased the number of the granulocytes and their mitotic index without inhibiting DNA fragmentation in the bone marrow cells as observed 24 and 48 h after the irradiation.

NADH can markedly prevent the damages to the hematopoietic system in mice exposed to irradiation, but the mechanism does not involve the inhibition of bone marrow cell apoptosis.

To study the protective effect of coenzyme I (NADH) on normal liver cell line L02 against ischemia-reperfusion injury.

Cultured L02 cells was divided into 3 groups, namely ischemia-reperfusion group (I/R), ischemia-reperfusion group with NADH pretreatment (NADH+I/R) and control group. Assisted by flow cytometry (FCM), the apoptosis rate and the expression of apoptosis-related proteins (Bcl-2, p16, p21, p53) were detected in L02 cells in the 3 groups. Apoptotic L02 cells were also observed under transmission electron microscope.

I/R significantly inhibited L02 cell proliferation and increased their apoptosis rate up to (31.53+/-8.27)% 12 h after I/R. In the presence of NADH, however, the apoptotic rate of the cells was significantly decreased to (12.61+/-2.34)% (P<0.05). FCM indicated that I/R down-regulated the expression of Bcl-2 and up-regulated the expression of p16, p21 and p53 proteins as compared with control group, but NADH acted to the reverse effect. Typical apoptotic features were observed by transmission electron microscope in the cells 12 h after I/R.

I/R might induce apoptosis in L02 cells by up-regulating the expression of p16, p21, p53 and down-regulating the expression of Bcl-2, and the protective effect of NADH against I/R-induced apoptosis may lie in the expression regulation of the proteins concerned.