Elevation of autophagy rescues spermatogenesis by inhibiting apoptosis of mouse spermatocytes.

Autophagy and apoptosis are interlocked in an extensive crosstalk. Our previous study demonstrated that hypotonic hypoxia-induced marked apoptosis of a spermatocyte-derived cell line (GC-2). However, whether hypoxia-induced apoptosis is mediated by inhibition of autophagy under hypoxic conditions remains unclear.

Hypoxia-induced apoptosis of mouse spermatocytes is mediated by HIF-1α through a death receptor pathway and a mitochondrial pathway.

Hypoxia in vivo induces oligozoospermia, azoospermia, and degeneration of the germinal epithelium, but the underlying molecular mechanism of this induction is not fully clarified. The aim of this study was to investigate the role of the death receptor pathway and the mitochondrial pathway in hypoxia-induced apoptosis of mouse GC-2spd (GC-2) cells and the relationship between HIF-1α and apoptosis of GC-2 cells induced by hypoxia. GC-2 cells were subjected to 1% oxygen for 48 hr.

Regulatory effects of autophagy on spermatogenesis.

Abnormal spermatogenesis is an important pathophysiological process underlying male infertility. Apoptosis of spermatogenic cells and disruption of ectoplasmic specialization (ES) have been characterized as the key biological events of this disorder. Under physiological and pathophysiological conditions (such as exposure to starvation, environmental chemicals, radiation), autophagy is activated in spermatogenic or Sertoli cells in order to maintain survival of the spermatogenic cells by inhibiting spermatogenic cell apoptosis and stabilizing the integrity of ES via degradation of PDZ and LIM domain 1 (PDLIM1), a negative regulator of cytoskeletal organization.

[Hypobaric hypoxia increases the expression of death receptor 5 and inhibits that of FLICE-like inhibitory protein in the rat testis].

Objective: To evaluate the effects of hypobaric hypoxia on the expressions of death receptor 5 (DR5) and cellular FLICE-like inhibitory protein (c-FLIP) and the distribution of c-FLIP in the rat testis.

Methods: Forty adult male SD rats were randomly divided into four groups of equal number: normoxia control, 3 d hypoxia, 15 d hypoxia and 30 d hypoxia. The control rats were raised at 300 m above the sea level, while the latter three groups of rats in a hypobaric chamber at a simulated altitude of 4000 m for 5, 15 and 30 days, respectively.

The antioxidant effects of garlic saponins protect PC12 cells from hypoxia-induced damage.

Hypoxia frequently occurs under several different cellular circumstances. Excess reactive oxygen species that are induced by hypoxia may result in cell injury and dysfunction. Recently, garlic has been found to possess some biological and pharmacological activities.

Hypoxic training increases metabolic enzyme activity and composition of alpha-myosin heavy chain isoform in rat ventricular myocardium.

Cardiac muscle adaptation is essential for maintaining physical capacity after ascending to high altitude. This study examines the effects of high altitude training on myocardial metabolic enzyme activity and composition of alpha-myosin heavy chain (MHC). Rats were randomly divided into normobaric sedentary (NS) and training (NT) groups, and hypobaric sedentary (HS) and training (HT) groups.

[Hypoxia promotes apoptosis of germ cells in rat testes].

Objective: To explore the effects of hypobaric hypoxia on the apoptosis of germ cells in male rats.

Methods: Adult male Wistar rats were randomly divided into four groups: a control group raised at sea level; a 5 d, a 15 d and a 30 d hypoxic group raised in a hypobaric chamber simulating 5000 m altitude for 5 days, 15 days and 30 days respectively. Flow cytometry and TUNEL were used to evaluate the apoptosis of germ cells in the testis.

[Hypoxia upregulates the expression of cytoglobin in lung cancer cells].

Objective: To explore the characters of expression of cytoglobin in tumor cells after hypoxia.

Methods: Human pulmonary tumor cells of the line A549 were cultured and divided into 4 groups to be cultured under 5% CO2 and 95% air and exposed to 2% O2, 5% CO2, and 93% N(2) for 4, 12, or 24 hours respectively. The distribution of cytoglobin was examined by immunohistochemistry and the expression of cytoglobin was detected by Western blotting.