Objective  To investigate protective effect of walnut oligopeptides (WOPs) on acute alcoholism in rats.

  Methods  Totally 140 specific pathogen free male Sprague-Dawley (SD) rats were randomly assigned into 4 groups for climbing, loss of righting reflex, and rotating rod test and blood ethanol concentration measurement; the rats in each of the 4 groups were subdivided into a model control group (with double distilled water), whey protein group (0.44 g/kg·BW) and 3 WOPs intervention groups (0.22 g/kg·BW, 0.44 g/kg·BW, 0.88 g/kg·BW); all the treatments were conducted by intragastric administration once a day continuously for 30 days. After the 30-day administration, the acute alcoholism model of the rats was established by intragastric administration of 50% alcohol at the dosage of 5.6 g/kg·BW (at the dosage of 7 g/kg·BW for the rats of loss of righting reflex test group). Then, the three behavioral tests were carried out and blood ethanol concentrations were measured at multiple time points.

  Results  Compared to the rats of model control and whey protein group, the rats treated with high WOPs had a significantly increased climbing time (the average rank of crawling time: 23.17 vs. 8.83 and 8.33) (both P < 0.05). In comparison to those of the rats in model control group, significantly reduced ratio of righting reflex disappearance (30% and 30% vs. 80%) and prolonged time for the disappearance of righting reflex (114.33 ± 50.50 and 128.33 ± 76.00 vs. 35.75 ± 32.14 min) were observed in the rats with moderate and high WOPs treatment (all P < 0.05); the recovery time of righting reflex in the rats treated with low, moderate and high WOPs were significantly shortened (369.25 ± 149.50, 331.67 ± 86.05 and 344.64 ± 107.53 vs. 711.25 ± 200.63 min) (P < 0.05 for all); the blood ethanol concentration was significantly decreased in the rats with low WOPs at 180 minutes after the 50% alcohol treatment (3.84 ± 0.86 vs. 5.51 ± 1.65 mg/mL) (P < 0.05); and significantly decreased blood ethanol concentrations were detected in the rats treated with moderate and high WOPs groups at 60 minutes (3.65 ± 0.69 and 3.79 ± 0.74 vs. 4.49 ± 0.96 mg/mL), 90 minutes (3.96 ± 0.75 and 3.99 ± 0.64 vs. 5.02 ± 1.06 mg/mL), 120 minutes (3.83 ± 1.16 and 3.78 ± 0.87 vs. 5.41 ± 1.27 mg/mL), and 180 minutes (3.22 ± 1.29 and 3.20 ± 1.31 vs. 5.51 ± 1.65 mg/mL) after the 50% alcohol treatment (P < 0.05 for all). Compared with those in the rats of whey protein group, significantly shortened recovery time of righting reflex were observed in the rats with moderate and high WOPs treatment (331.67 ± 86.05 and 344.64 ± 107.53 vs. 594.37 ± 198.06 min) (both P < 0.05) and significantly reduced blood ethanol concentrations were detected in the rats with moderate WOPs treatment at 180 minutes (3.22 ± 1.29 vs. 4.94 ± 1.31 mg/mL) in the rats with high WOPs treatment at 120 minutes (3.78 ± 0.87 vs. 5.06 ± 0.89 mg/mL) and 180 minutes (3.20 ± 1.31 vs. 4.94 ± 1.31 mg/mL) after the 50% alcohol treatment (P < 0.05 for all).

  Conclusion  Oral intake of walnut oligopeptides can effectively reduce the damage of acute alcoholism in rats.