Oyama, N. | Search bioRxiv

bioRxiv2026

Selective depletion of AMH-expressing granulosa cells in vivo impairs follicular development and fertility in female mice

In mammals, ovarian follicle development is a highly coordinated process that underlies female fertility. Granulosa cells expressing anti-Mullerian hormone (AMH) are widely used as a marker of growing follicles. However, the in vivo roles of granulosa cells in follicular development and female fertility remain unclear. Here, we analyzed AMH-toxin receptor-mediated cell knockout (AMH-TRECK) transgenic (Tg) mice on a NOG background, in which AMH-expressing granulosa cells are specifically depleted by diphtheria toxin (DT). We first found that, after a single DT injection into postnatal AMH-TRECK Tg females, AMH-expressing granulosa cells in primary and secondary follicles exhibited cleaved caspase-3 signals 1 day later and were depleted 4 days later. Second, after repeated DT injections weekly from 1 to 7 weeks of age in AMH-TRECK Tg females, antral follicles and corpora lutea were rarely observed, and the numbers of primordial, primary, and secondary follicles were decreased. Following PMSG and hCG stimulation, repeated DT-injected Tg females exhibited a reduced number of ovulated oocytes with a low proportion of mature oocytes, resulting in reduced IVF rates and fertility. Further, after a cessation of repeated DT treatment, ovarian weight and follicular development recovered: the numbers of primary, secondary, and antral follicles were recovered, whereas the primordial follicle pool remains reduced. We conclude that selective depletion of AMH-expressing granulosa cells in vivo impairs follicular development and fertility. Our model enables assessment of the in vivo effects of granulosa cell depletion and may provide a useful platform for future transplantation-based studies to understand complex follicular dynamics.

developmental biology↗

bioRxiv2019

Cardiovascular effects of intravenous colforsin in normal and acute respiratory acidosis canine models: a dose-response study

AbstractIn acidosis, catecholamines are attenuated and higher doses are often required to improve cardiovascular function. Colforsin activates adenylate cyclase in cardiomyocytes without mediating the beta adrenoceptor. In this study, six beagles were administered either colforsin or dobutamine four times during eucapnia (partial pressure of arterial carbon dioxide 35-40 mm Hg; normal) and hypercapnia (ibid 90-110 mm Hg; acidosis) conditions. The latter was induced by carbon dioxide inhalation. Anesthesia was induced with propofol and maintained with isoflurane. Cardiovascular function was measured by thermodilution and a Swan-Ganz catheter. Cardiac output, heart rate, and systemic vascular resistance were determined at baseline and 60 min after 0.3 g/kg/min (low), 0.6 g/kg/min (middle), and 1.2 g/kg/min (high) colforsin administration. The median pH was 7.38 [range 7.34-7.42] and 7.04 [range 7.01-7.08] at baseline in the Normal and Acidosis conditions, respectively. Endogenous adrenaline and noradrenaline levels at baseline were significantly (P < 0.05) higher in the Acidosis than in the Normal condition. Colforsin induced cardiovascular effects similar to those caused by dobutamine. Colforsin increased cardiac output in the Normal condition (baseline: 198.8 mL/kg/min [range 119.6-240.9], low: 210.8 mL/kg/min [range 171.9-362.6], middle: 313.8 mL/kg/min [range 231.2-473.2], high: 441.4 mL/kg/min [range 373.9-509.3]; P < 0.001) and the Acidosis condition (baseline: 285.0 mL/kg/min [range 195.9-355.0], low: 297.4 mL/kg/min [213.3-340.6], middle: 336.3 mL/kg/min [291.3-414.5], high: 366.7 mL/kg/min [339.7-455.7] ml/kg/min; P < 0.001). Colforsin significantly increased heart rate (P < 0.05 in both conditions) and decreased systemic vascular resistance (P < 0.05 in both conditions) compared to values at baseline. Systemic vascular resistance was lower in the Acidosis than in the Normal condition (P < 0.001). Dobutamine increased pulmonary artery pressure, whereas colforsin did not. Colforsin offsets the effects of endogenous catecholamines and may not increase cardiac output during hypercapnia.

pharmacology and toxicology↗