The effects of low ambient temperature on steroidogenesis and mitochondrial functions in the testes of wild ground squirrels (Spermophilus dauricus).

Seasonal reproduction is a widely used breeding strategy in wildlife, especially vertebrates inhabiting temperate regions. Generally, ambient temperature is considered a significant factor influencing the reproductive status of animals. In the present study, wild ground squirrels (Spermophilus dauricus), typical seasonal breeders, were used as an animal model to investigate the mechanism behind the impact of low ambient temperature on testicular function. To simulate the winter environment of wild ground squirrels, we lowered the temperature gradient in the rearing environment to 4 °C. At sampling, the body surface temperature of the squirrels reared under normal ambient temperature (22 °C, NAT group) and the low ambient temperature (4 °C, LAT group) were 31.5 °C and 22.8 °C, respectively. Subsequently, we conducted immunohistochemical assays, qPCR, and enzyme-linked immunosorbent assays (ELISA) to examine the variations in testicular functions, as well as the dynamics and functions of mitochondria, in the squirrels of NAT and LAT groups. As a result, the levels of positive immunostaining for PCNA, P21, and P27 were significantly lower in the testes of LAT group, while the levels of immunostaining for Cleaved Caspase-3 and TUNEL were significantly higher. In addition, the low-temperature treatment reduced the expression level of steroidogenesis-related genes, including LHR, FSHR, GATA-4, P450scc, and P450arom, and decreased the testosterone concentration. Moreover, markers of mitochondrial fission and fusion, DRP1 and MFN2, respectively, were increased in the testes of LAT group. Additionally, the mRNA level of SOD1 was notably higher in the testes of LAT group. In conclusion, the low ambient temperature inhibited spermatogenesis, steroidogenesis, as well as mitochondrial dynamics and functions in the testes of wild ground squirrels.

Immunoreactivities of AR, ERα, ERß and aromatase in the nuptial pad of Chinese brown frog (Rana dybowskii) during pre-hibernation and the breeding period.

There is a prominent local raised pad called nuptial pad on the forelimb of Chinese brown frog (Rana dybowskii), which is hypothetically concluded as an enhancement of the grip and a spreader of pheromone during the amplexus. In this study, we investigated the immunolocalization and protein expression levels of AR, ERα, ERß and aromatase in the nuptial pad of R. dybowskii during pre-hibernation and the breeding period. Histologically, the annual development of the nuptial pad in R. dybowskii is manifested as the larger area of specialized mucous gland and the longer length of papillary epidermal projection during the breeding period. AR, ERα, ERß and aromatase are present in the stratum granulosum, stratum spinosum, stratum basale and the secretory portion of specialized mucous glands during both periods. Western blotting results confirmed that AR, ERα and ERß protein levels are higher during pre-hibernation than those during the breeding season. These results suggest that nuptial pad is the direct target organ of androgen and estrogen. Androgen may participate in the regulation of annual development and glandular function of nuptial pad, and estrogen may play an endocrine, autocrine or paracrine role during pre-hibernation and the breeding period.

[Epidemiological study on status of Helicobacter pylori in children and teenagers in Wuwei city, Gansu province].

OBJECTIVE: To investigate the prevalence of Helicobacter pylori (Hp) infection among children aged 3 to 18 years old of Wuwei city, Gansu province. METHODS: The study was based upon a personal questionnaire and a determination of Hp antigen using the Hp stool antigen test (HpSA) method. A total of 938 subjects and 96 families were selected in Wuwei city. Eighty children and teenagers with a definite positive Hp stool antigen test were examined by serum Western blotting method. RESULTS: The prevalence of Hp was 72.3% (678/938) with no age difference. Prevalence of Hp infection was correlated with type of dwelling, occupation of parents, drinking water source, kindergarten attendance, consumption of raw vegetables, a poor oral hygiene and breast feeding etc. According to the multivariate analysis, drinking water source, kindergarten attendance and consumption of raw vegetables were most strongly associated with prevalence of Hp in children and adolescents. The infection rate of parents whose children were infected with Hp was higher than that of those whose children were not infected [82.3% (121/147) vs 47.4% (18/38), chi(2) = 19.736, P < 0.05]. The antibody responses of 57 samples (71.3%) from 80 children were of type I Hp and 23 samples (28.7%) type II. CONCLUSIONS: Hp infective rate is high in Wuwei city. The data support maternal-child and sibling-sibling transmission as the primary transmission routes of Hp. The results of serological analysis confirm that the majority of Wuwei Hp infection is of type I.