The Effect of Pentadecapeptide BPC 157 on Episcleral Vein Cauterization Model in Rats

Aim Glaucoma is an irreversible optic nerve neuropathy. This study aimed to evaluate the effect of BPC 157 on glaucoma‐like features in the rat episcleral vein cauterization model. Methods We used female Albino Wistar rats, 200g, randomly divided onto the treated and control groups. After application of Ketmine‐HCl 50–60 mg/kg + Xylazine‐HCl 5–10 mg/kg, Tetrakain 0,5% drops, two dorsal episcleral veins and one temporal episcleral vein were isolated from the surrounding tissues. A cautery was specifically applied to the selected vein. Early treatment rats received (pentadecapeptide BPC 157 (10μg/kg) (Diagen, Slovenia) intraperitoneally) immediately after surgery while alternatively delayed treatment received at 24h after. Controls received an equivolume of 0.9%NaCl (5ml/kg) intraperitoneally. Intraocular pressure (IOP) (% of normal IOP), pupillar function were measured 24h and 48 hours after procedure. Non‐invasive IOP measurements were taken after local application of Tetrakain 0,5%, by aplanation tonometer Tonopen XL in same time of a day. Pupillar function was photographed by USB Veho Discovery VMS‐004 Deluxe microcamera. Photographs were taken before and after application of BPC 157 or saline and analyzed with special software bought with camera for measurement of pupillar diameter (r=mm), range (C=mm) and surface (S=mm 2 ). Camera was previously calibrated using graph paper. Vascularization of the eye fundus and presentation of papilla n. optici were analyzed with microcamera and Digital Widefield lupe 90D at 4 weeks after procedure. We focused our images on the vessels extending into and out of the optic disc. Retinal changes alterations in vessel caliber and tortuosity, optic disc pallor and leakage of the retinal arterioles and venulas were observed and scored (Score 1–3). Results Early treatment. At 24 hours after surgery control rats exhibited the following values (r=1.3±0.1, C=7.3±0.4, S=6.0±0.2, IOP=135%). BPC 157 group values were: r=0.14±0.03, C=1±0.05, S=0.1±0.03, IOP=105%. Delayed treatment. At 24h all rats exhibited significant failure (presentation before treatment (r=1.4±0.2, C=8.3±0.3, S=7.0±0.4, IOP 135%) that equally persisted for next 24h till the 48h after surgery (r=1.4±0.2, C=8.3±0.3, S=7.0±0.4, IOP 135%). On the other hand, these were completely counteracted by subsequent administration of BPC 157 as evidenced in next 24 h, at 48h post‐surgery (r=0.26±0.04. C=1.6±0.1. S=0.42±0.05, IOP=104%). In all BPC 157 treated animals there was only slight generalized vessel caliber irregularity (difference in diameter between arteries and veins) with a vaguely atrophic optic disc and an area not bigger than 1 optic disc diameter containing leaking of retinal vessels (Score 1). In control animals there was either moderate generalized vessel caliber irregularity (bigger difference in diameter between arteries and veins with moderate overfilling of veins) with moderate atrophic optic discs and an area ranging between 1–3 optic disc diameters containing leaking of retinal vessels (Score 2) or severe generalized vessel caliber irregularity (very big difference in diameter between arteries and veins with severe overfilling of veins) with severe atrophic optic disc and an area more than 3 optic disc diameters with leaking of retinal vessels (Score 3). Conclusion Pentadecapeptide BPC 157 used intraperitoneally counteracts the effects of episcleral vein cauterisation. Support or Funding Information This research was supported by grant 108‐1083570‐3635 from Ministry of Science, Education and Sports, Republic of Croatia