β-Carotene, a natural additive that is often used for food coloring, is converted into vitamin A in the body and it removes reactive oxygen species. β-Carotene accumulates in the liver and adipose tissue, where it can induce adverse effects if present in excess. In this study, we determined whether β-carotene supplementation of a high-fat/high-sucrose diet enhances liver inflammation and fibrosis in Mongolian gerbils, which accumulate β-carotene in the liver. Ten-week-old male Mongolian gerbils were divided into four groups and fed either a normal diet, a high-fat/high-sucrose diet, a high-fat/high-sucrose diet supplemented with a low dose of β-carotene (0.001%), or a high-fat/high-sucrose diet supplemented with a high dose of β-carotene (0.004%). An oral glucose tolerance testing was performed after 12 weeks, and non-fasted serum and tissue samples were collected after 13 weeks of diet feeding. The high dose of β-carotene increased triglycerides and total cholesterol serum concentrations. Intake of a high-fat/high-sucrose diet with a high dose of β-carotene increased the β-carotene content, volume occupied by fat droplets, degree of fibrosis, and protein levels of matrix metalloprotease-9 (a marker of inflammation in steatohepatitis) in the liver. These data suggest that the intake of excessive amounts of β-carotene for 13 weeks exacerbates high-fat/high-sucrose diet-inducible inflammation and fibrosis in the liver in Mongolian gerbils. This model is suitable for studying the mechanism of β-carotene-induced liver injury, including liver fibrosis.

D-allulose is a rare sugar with an almost zero calorie and is known to suppress postprandial hyperglycemia and fat mass accumulation. Although D-allulose has been reported to be safe in healthy subjects and overweight/obese adults, its safety in borderline diabetes and diabetes patients has not been evaluated. Therefore, we conducted an open trial aimed to investigate the long-term safety of D-allulose in borderline diabetes and type 2 diabetes. Subjects took 5 g of D-allulose with meals three times daily for 12 continuous weeks. The general blood biochemical parameters, hematological parameters, urinary parameters, and anthropometric indicators were measured at 0, 2, 4, 8, and 12 weeks of the consumption periods and 4 weeks after completing consumption. Adverse events were assessed by the principal physician on each examination day. A total of 12 and 6 subjects with borderline and type 2 diabetes, respectively, were analyzed. No serious clinical problems were found in this study, although significant cholesterol variations and the improvements of some indicators of hepatic function were observed. In conclusion, the long-term ingestion of D-allulose is safe in borderline diabetes and type 2 diabetes. D-allulose can potentially suppress postprandial hyperglycemia and fat mass accumulation, and thus might be useful in diabetes.

Rare sugar D-allulose prevents obesity; however, an excessive and continuous intake of D-allulose may induce weight increases in the liver and kidney without apparent pathological and functional abnormalities. Conversely, there has not been reported about how these parameters will change after cessation of D-allulose intake. In this study, effects of a 10-week D-allulose cessation on liver and kidneys weights and biomarkers were investigated in rats previously fed a D-allulose containing diet for 4 weeks. Wistar rats were fed a control diet (C, n=16) or a 3% D-allulose diet (DA, n=16) for 4 weeks, and then the half of rats in the C and DA subgroups were dissected, while the other half of rats were fed the control diet for 10 weeks (C-C and DA-C, n=8, respectively). At the end of the first 4 weeks period, halves of rats in each diet group were euthanized, and the serum, urine, liver, and kidneys were used for pathological and biochemical analyses. The remaining rats were also similarly treated at the end of latter 10 weeks treatment. At week 4, the relative weights of the liver and kidneys were higher in the DA group than in
the C group, but these differences were disappeared by cessation of D-allulose. No abnormal parameters related to liver and kidneys functions were observed in the serum and urine. These findings suggested that D-allulose-induced increases in the liver and kidneys weights could be recovered to the normal levels by D-allulose cessation without accompanying functional and pathological abnormalities.

Cisplatin (CP) is used as a chemotherapeutic drug for the treatment of various kinds of cancer. However, it is becoming increasingly difficult to ignore its side effects, especially nephrotoxicity which has to do with oxidative stress and inflammation. Procyanidin (PRO) has been proved to be a powerful antioxidant. Therefore, we investigated whether PRO could prevent Cisplatin-induced nephrotoxicity and explored the underlying mechanism. In cellular experiment, reactive oxygen species (ROS), the malondialdehyde (MDA) levels, the activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX) were measured for the assessment of cisplatin-induced oxidative cell damage. CCK-8 reagent and flow cytometry were used to detect the cell viability and apoptosis. Furthermore, the level of oxidative-related protein Nrf2 and HO-1 were carried out by western blot analysis. We found that cisplatin gave rise to the elevated levels of ROS and MDA and the decrease of the activities of T-SOD and GSH-PX with a related lower viability and higher apoptosis in HK-2 cells. Inversely, the pretreatment of PRO mitigated the oxidative damage, promoted the cell viability and lowered the apoptosis, activated nuclear related factor 2 (Nrf2) and elevated the expression of heme oxygenase-1 (HO-1), the above cytoprotection of PRO was blocked by siNrf2 or siHO-1. These results demonstrated that PRO has the potential to prevent cisplatin-induced nephrotoxicity through activation of Nrf2/HO-1 signaling pathway.

The Sprague-Dawley (SD) rat has been widely used for general toxicity and toxicokinetic (TK) studies, and is also useful for phototoxicity assessments. We previously showed that phototoxicity assessments could be incorporated into general toxicity study. However, this research was performed at only one facility. Thus, the effects of repeated administration and TK blood collection were investigated in three facilities to explore the possibility of incorporating phototoxicity assessments into general toxicity study. Lomefloxacin and pirfenidone were tested as the phototoxic compounds. Six-week-old male and female SD rats were allocated to two groups for each compound: single-dose and repeated-dose. The single-dose group was irradiated after a single administration of the drug without blood collection for TK. The repeated-dose group was irradiated after 8 days of repeated administration of the drug with TK blood collection (total 0.72-0.84 mL) after the 1st and 7th administration. Phototoxic reactions on the ventral skin, dorsal skin, and auricle skin were observed macroscopically at 2, 24, 48, and 72 hr after irradiation, and skin reaction scores were evaluated. The phototoxic compounds produced skin reactions in rats at all facilities regardless of the presence or absence of repeated administration and TK blood collection. However, there were differences in the degree of skin reaction between the two groups and among the facilities. Although further studies are needed to standardize this new evaluation system, we expect that the incorporation of phototoxicity assessments will contribute to shortening the research and development period and support the 3R principle for animal experiments.