Experimental Tibetan monkey domestication and its application for intraocular pressure measurement

Using a Novel, Subconjunctival, Sustained-Release Mitomycin C Formulation in a Rabbit Model of Filtration Surgery with Gel Stent Implantation

Purpose: To investigate gel stent implantation with and without intraoperative sustained-release mitomycin C (MMC SR) in a rabbit model for gel stent implantation, and to examine aqueous humor outflow (AHO) postimplantation. Methods: Four groups of rabbits were included. Group 1 was untreated (control). Groups 2, 3, and 4 received the gel stent without MMC, with MMC solution (subconjunctival injection), and with MMC SR (subconjunctival injection), respectively. Intraocular pressure (IOP) and AHO were assessed via tonometry and indocyanine green-based angiography, respectively. The main efficacy measure was change in IOP from baseline. Results: Following gel stent implantation, Groups 2, 3, and 4 maintained ≥20% IOP reduction (response) for a median duration of 1 week, 6.5 weeks, and 30 weeks, respectively. Angiography showed normal aqueous humor drainage (Group 1) beginning at the perilimbal trabecular plexus and continuing posteriorly to episcleral outflow vessels. Following implantation, drainage occurred preferentially and directly into the subconjunctival bleb. Conclusions: Gel stent implantation with MMC SR was most effective in achieving sustained, long-term IOP reduction in the rabbit model, compared with implantation with or without MMC solution. Bleb presence and the postimplantation aqueous angiography results indicated redirection of the AHO to the subconjunctival vasculature and presumed lymphatics, suggesting efficient glaucoma filtration to lower IOP in this model. This rabbit model and aqueous angiography may help refine understanding of the mechanism of action of minimally invasive glaucoma surgeries and ultimately translate to improved surgical devices and procedures for patients with glaucoma.

Identification and characterization of short tandem repeats in the Tibetan macaque genome based on resequencing data

The Tibetan macaque, which is endemic to China, is currently listed as a Near Endangered primate species by the International Union for Conservation of Nature (IUCN). Short tandem repeats (STRs) refer to repetitive elements of genome sequence that range in length from 1-6 bp. They are found in many organisms and are widely applied in population genetic studies. To clarify the distribution characteristics of genome-wide STRs and understand their variation among Tibetan macaques, we conducted a genome-wide survey of STRs with next-generation sequencing of five macaque samples. A total of 1 077 790 perfect STRs were mined from our assembly, with an N50 of 4 966 bp. Mono-nucleotide repeats were the most abundant, followed by tetra- and di-nucleotide repeats. Analysis of GC content and repeats showed consistent results with other macaques. Furthermore, using STR analysis software (lobSTR), we found that the proportion of base pair deletions in the STRs was greater than that of insertions in the five Tibetan macaque individuals (P<0.05, t-test). We also found a greater number of homozygous STRs than heterozygous STRs (P<0.05, t-test), with the Emei and Jianyang Tibetan macaques showing more heterozygous loci than Huangshan Tibetan macaques. The proportion of insertions and mean variation of alleles in the Emei and Jianyang individuals were slightly higher than those in the Huangshan individuals, thus revealing differences in STR allele size between the two populations. The polymorphic STR loci identified based on the reference genome showed good amplification efficiency and could be used to study population genetics in Tibetan macaques. The neighbor-joining tree classified the five macaques into two different branches according to their geographical origin, indicating high genetic differentiation between the Huangshan and Sichuan populations. We elucidated the distribution characteristics of STRs in the Tibetan macaque genome and provided an effective method for screening polymorphic STRs. Our results also lay a foundation for future genetic variation studies of macaques.

Effects of age and sex on the hematology and blood chemistry of Tibetan macaques (Macaca thibetana)

Tibetan macaques (Macaca thibetana), also known as Chinese stump-tailed macaques, are a threatened primate species. Although Tibetan macaques are Old World monkeys in the genus of Macaca, limited age- and sex-related physiologic data are available for this particular species. We used 69 apparently healthy Tibetan male and female macaques to explore the effect of age and sex on physiologic parameters. Somatometric measurements, biochemistry, and hematologic parameters were analyzed. Significant age-related differences were found for weight, BMI, RBC count, Hgb, Hct, neutrophils, eosinophil count, ALT, AST, ALP, GGT, creatine kinase (muscle and brain subtypes), LDH, α-amylase, creatinine, apolipoprotein A1, total protein, albumin, cholesterol, HDL, and potassium. Significant differences by sex were noted for weight, BMI, ALT, total bilirubin, and indirect bilirubin. An interaction between age and sex accounted for statistically significant differences in the values for weight, BMI, and lymphocyte and eosinophil counts. These physiologic data will provide veterinarians and researchers with important age- and sex-specific reference ranges for evaluating experimental results from Tibetan macaques.