Crocin mitigated cognitive impairment and brain molecular alterations induced by different intensities of prenatal hypoxia in neonatal rats.

INTRODUCTION: Brain hypoxia has important role to the onset and progression of sporadic form of Alzheimer disease via expression of hypoxia-inducible factor-1 (HIF-1). Crocin by anti-amyloidogenic property inhibits ß-amyloid formation. However, the molecular mechanism associated with anti-amyloidogenic activity of crocin is unknown. So, the present study was designed to investigate the effect of crocin on cognitive behavior and expression of HIF-1α and ß-secretase (BACE1) genes in the brain of neonate rats following different intensities of hypoxia during pregnancy. MATERIAL AND METHODS: Pregnant female rats were divided into six groups including sham, control crocin treated (CC), hypoxia with three different intensities (H1-H3), and most intense of hypoxic group treated with crocin (H3C) (30 mg/kg; i.p) at P14. Hypoxia induced on the 20th day of pregnancy. Animals in sham and CC were put in hypoxia chamber at the same time of hypoxia group without any hypoxia induction. Morris water maze (MWM) and qRT-PCR were used to evaluate the cognitive behavior and mRNA levels of BACE1 and HIF-1α genes in the brain tissues. RESULTS: Animal under 7% O2  + 93% N2 condition for 3 hr showed the highest cognitive behavior impairment and upregulated HIF-1α and BACE1 mRNA in brains of offspring (p < .001). Crocin treatment improved memory impairment and attenuated the gene expression of HIF-1α and BACE1 in the brains of neonate rat. CONCLUSIONS: It was concluded that crocin has beneficial effects on the brain of neonate rats under gestational hypoxia by improvement of memory impairment and molecular alteration related to hypoxia.

Crocin Treatment after Maternal Hypoxia Attenuates Spatial Memory Impairment and Expression of BACE1 and HIF-1α in Rat Offspring Brain.

INTRODUCTION: Hypoxia via expression of Hypoxia-Inducible Factor-1 (HIF-1) is an important and effective factor in the onset and progression of memory disorders, such as Alzheimer Disease (AD). The activity of ß-secretase (BACE1) is increased in hypoxia conditions. BACE1 triggers a cascade of pathological events resulting in AD. Crocin acts as a memoryimproving agent but its molecular mechanism is not well-known. Therefore, in this study, the effect of crocin on spatial memory, HIF-1α, and BACE1 gene expression was investigated in rat offspring under maternal hypoxia. METHODS: Female pregnant rats on the 20th day of pregnancy were divided into 4 groups, including sham, crocin-treated, hypoxia, and hypoxia group treated with crocin. In the hypoxia groups, pregnant rats were exposed to 7% oxygen and 93% nitrogen intensity for 3 h. In the crocin-treated group, crocin (30 mg/kg) was injected at P14-28 (i.p). At the end, Morris water maze was used to assess spatial memory and real-time polymerase chain reaction was performed to measure the expression of BACE1 and HIF-1α genes in the brain of offspring. RESULTS: Maternal hypoxia impaired memory compared with the sham group. However, crocin treatment improved cognitive behavior. HIF-1α and BACE1 expressions were upregulated in the brain of offspring in the hypoxia group. Crocin treatment could attenuate the expression of both genes. CONCLUSION: According to our results, down-regulation of HIF-1α and BACE1 gene expressions in the brain of rat offspring after crocin treatment can be suggested as a molecular mechanism for crocin to improve spatial memory.